***Useful Information For The Working Sparky***

[amberleaf]

“ Rcd's “

Fire detection circuits must be supplied independently of other circuits and not protected by an Rcd protecting multiple circuits. 560.7.1 All circuits in a bath shower room must be protected by a 30mA RCD. P166, 701.411.3.3
Where applicable an RCD notice must be fixed on or next to the CCU 514.12.2 An RCD should not be used as a main switch 314.2 If the maximum Zs values for a circuit in a TN systems cannot be met, the circuit may be protected by a 30mA RCD. 531.3.1
If the maximum Zs values for a TN systems cannot be met, the installation may be protected by an 100mA RCD and treated as a TT systems . 531.3.1 : 411.5.1 : 411.5.2 : 411.5.3
Unless specifically labelled or suitably identified, all 13A socket outlets must be protected by a 30mA Rcd. 411.3.3
In a TN systems , the part of a lighting circuit in a bath or shower room is required to be 30mA RCD protected. 411.3.3 , 701.411.3.3

Where a cable is buried in a wall or partition at a depth of less than 50mm on either side it must be sufficiently mechanically protected against penetration OR RCD protected AND installed either horizontally within 150mm of the top of the wall or vertically within 150mm of the angle formed where two walls meet or run horizontally or vertically to an accessory, luminaire or CCU 522.6.6 , 522.6.7 . This applies to a cable in a partition constructed using metallic parts other than fixings irrespective of the cable depth. 522.6.8

Surface run cables do not require RCD protection. OSG p22

A single RCD protecting a TT systems must be installed at the origin of the installation unless the part of the system between the origin and the RCD fulfils the requirements for protection by Class 11 equipment or equivalent insulation 531.4.1

All Electrical equipment must be accessible for operation , inspection & testing maintenance and repair. 132.12

Rcd Test Procedure

Many RCD test meters have a facility where tests can be carried out during the positive or negative half of the supply cycle. For tests 1 & 2 the RCD operating time to be recorded is the longer of the two measured during the half cycle tests.

DO NOT press the test button on the RCD before testing as this can temporarily reset a faulty RCD

Test 1
Adjust the current setting on the test meter to 100% of the rated trip current of the RCD and perform a test. A general purpose BS4293 RCD should operate within 200mS . A general purpose BS-61008 RCD or RCBO to BS-61009 should operate within 300ms

Test 2
An RCD provided for Basic Protection should have a rated TRIP current not exceeding 30mA If the RCD is rated at 30mA , adjust the current setting on the test meter to 150ma ( x5 ) and perform a test. The RCD must operate in a time not exceeding 40mS.
Test 3
Adjust the current setting on the test meter to 50% of the RCD trip current and perform a test. The RCD should not operate within 2 seconds
The Test Button : Finally operate the RCD by pressing its test button

 

[Spudnik]

Re: useful information

Another useful post there Mr Leaf.

Ill stick this one too, and i would respectfully ask members to refrain from posting here so that we can keep the thread clear.

Thanks.

 

[amberleaf]

“ Certification & Reporting “
Before an Installation or an additions & alterations’ to an installation is energised, inspection and testing must be carried out to ensure the requirements of BS-7671 have been met and an appropriate certificate must then be issued. ( 134.2.1, 610.6 631.1 )
Steps must be taken to avoid damage to property and equipment and to avoid danger and injury to persons during inspection and testing. 610.1
Any defects found in the existing installation must be recorded on the Electrical Installation Certificate or Minor Electrical Installation Works Certificate. 633.2
A durable copy of the schedule from the electrical installation certificate must be fixed next to or placed inside the consumer unit. In addition to circuit details the schedule must a contain information about the protective measures used in the installation i.e. automatic disconnection of supply, electrical separation SELV , RCD, 132.13 514.9

The Periodic Inspection Report must only be used to report on the condition of an existing installation. p339

BS-7671 does not give specific details on the frequency of periodic inspection & testing of a domestic installation. 622.1. Guidance Note 3 suggests every 10 years or every change of occupancy.

The Minor Works Certificate must only be used where additions & alterations’ to an existing installation do not include a new circuit. p336 , 631.3

The Electrical Installation Certificate must only be used to certify a new installation, new circuits in an existing installation or new work that includes additions & alterations’ to an existing installation. An Electrical Installation Certificate must not be used to report on the condition of an existing installation. p334 , 631.1

NICEIC Domestic Electrical Installation Certificates require that an additional 'Certificate of Design, Installation & Commissioning Of A Fire Detection & Alarm System Of Grade B, C, D, E or F In A Dwelling' must be provided for any fire detection systems including smoke alarms that are part of the installation.

Electrical separation is a protective measure for circuits up to 500v ac. 413.3.2 An example of electrical separation in a domestic installation is a shaver socket.
Protection by electrical separation in a bathroom or shower must only be used for :
a. one single socket outlet, or

b. circuits supplying one item of current using equipment 701.413

All circuits in a bathroom or shower room must be protected by a 30ma RCD p166, 701.411.3.3

Only one item of current using equipment may be supplied using electrical separation. 413.1.2, 701.413

All items of current using equipment must be provided with a functional switching device. 537.5.1.3

Electrical floor heating systems must not be supplied using electrical separation. 701.753

All electrical equipment must be accessible for operation, inspection & testing, maintenance and repair. 132.12

For more information on electrical separation see 413.1, 418.3, 701.1, 612.4.3

“ Incoming Supply “

A main switch must be provided to cut off the voltage to an installation. 132.15.1 *

A double pole main switch or linked circuit breaker must be installed as close as possible to the incoming supply at the origin of the installation. 537.1.4 *

If an installation in the United Kingdom does not comply with Chapter 13 of BS-7671 the electricity supplier does not have to provide a supply to the property. p241 *

A TN-S supply has separate neutral and protective conductors. All the exposed conductive parts of the installation must be connected to the protective conductor at the main earthing terminal. p30, p33 *

A TN-C-S supply has a combined neutral and protective conductor. All the exposed conductive parts of the installation must be connected to the combined neutral and protective conductor at the main earthing terminal. This type of system is also known as PME (protective multiple earthing). p30, p33 *

PME submains are not permitted. 543.4.9 *
230v final circuits in a TN system not rated greater than 32A must disconnect within 0.4 seconds under fault conditions. 411.3.2.2 *
Under fault conditions in a TN system, circuits over 32A including distribution circuits must disconnect within 5 seconds. 411.3.2.3 *
If the maximum Zs value for a circuit in a TN system cannot be met, the circuit may be protected by a 30ma RCD. 531.3.1 *
If the maximum Ze value for a TN system cannot be met, the installation may be protected by a 100ma RCD and treated as a TT system. 531.3.1 , 411.5.1 , 411.5.2 , 411.5.3 *
A TT supply has the exposed conductive parts of the installation connected to an earth electrode which is separate from the earth of the supply. p30 , p34 *
A single RCD protecting a TT system must be installed at the origin of the installation unless the part of the system between the origin and the RCD fulfils the requirements for protection by Class II equipment or equivalent insulation . 531.4.1 *
230v final circuits in a TT system not rated greater than 32A must disconnect within 0.2 seconds under fault conditions. If disconnection is made by a fuse or mcb and all extraneous conductive parts are connected to the main equipotential bonding then a disconnection time of 0.4 seconds is permitted. 411.3.2.2
Under fault conditions in a TT system, circuits over 32A including distribution circuits must disconnect within 1 second. 411.3.2.4 *
For more information about TT systems see 411.5.2, 612.8.1 * It is assumed that where an installation is supplied in accordance with the Electricity Safety, Quality and Continuity Regulations 2002 the connection between the supply neutral and earth is permanent. 114.1 *
The incoming supply to a domestic property is 230v with a permitted tolerance of +10% / - 6% ie 216.2v - 253.0v. p 242 *
Meter tails are part of the consumers installation and are to be provided by the installer. Meter tails must be sheathed and insulated or if insulated only must be enclosed in trunking or conduit. Meter tails must be 25mm. Where the meter tails are protected against fault current by the main fuse the installation method, maximum length and minimum cross sectional area must meet the distributors requirements. OSG p17
A distribution circuit is the circuit that connects the incoming supply to the ccu i.e. meter tails. When a distribution circuit supplies an installation remote from the incoming supply it is sometimes referred to as a sub main. p23

Extractor Fans Extractor fans must be provided with an easily accessible means of switching off the supply 132.15.2 Electrical Equipment that may cause injury during mechanical maintenance i.e. fans, must be provided with a means to switch off the supply. 537.3.1.1 All items of current using Equipment must be provided with a functional switching device. 537.5.1.3 All Electrical Equipment must be accessible for operation, inspection & testing , maintenance and repair. 132.12
“ Immersion Heaters “
An immersion heater must not be supplied by a ring final circuit. p362, 433.1.5
An immersion heater must be connected to the supply by a double pole linked switch only. The use of a plug top and socket outlet is not permitted. 554.3.3
An immersion heater must be provided with a thermal cut-out to prevent the water from boiling if the thermostat fails. 554.2.1
All final circuits must be wired separately from all other final circuits. 314.4
All Electrical Equipment must be accessible for operation, inspection & testing, maintenance and repair. 132.12

 

[amberleaf]

“ Lighting Circuits “
All electrical equipment must be accessible for operation, inspection & testing, maintenance and repair. 132.12 Where an installation has only one lighting circuit, the circuit may need to be divided into two circuits to minimize the danger that may arise in the event of a fault. 314.1 (iii) Light fittings must be installed so that any radiated heat does not cause any damage. 559.5.1 The fixing supporting a light fitting must be able to support a weight of at least 5kg. 559.6.1.5 Domestic lighting circuits should not be rated at more than 16A. 559.6.1.6 Edison screw lampholders (excluding types E14, E27 ) should have the outer contact connected to the neutral conductors’ . 559.6.1.8 Lighting circuits must be controlled by the appropriate number of switches. 559.6.1.9 p146 Through wiring is only permitted in a light fitting where the light fitting is designed for such wiring. 559.6.2.1 p146 Through wiring in a light fitting must be suitable for the temperature generated inside the fitting. 559.6.2.2 The lamp inside an outdoor light fitting mounted less than 2.8m above the ground must only be accessible after removing an enclosure or barrier with the use of a tool. 559.10.3.1 Electrical equipment outdoors must be rated at least IP33. 559.10.5.2 Switch lines must be marked brown at their terminations. 514.3.1, p91

Lighting Circuits In A Bath Or Shower Room
In a TN Systems the part of a lighting circuit in a bath or shower room is required to be 30ma RCD protected. P47 , 411.3.3 , p166 , 701.411.3.3 Electrical equipment installed within zone 0 must be at least IPX7. 701.512.2 Only switches that are built into fixed Electrical equipment and the insulated pull cords of pull cord switches are permitted in zone 0. No other switches or accessories are allowed. 701.512.3 Only SELV equipment not exceeding 12v ac or 30v dc is permitted in zone 0. The SELV equipment must be fixed and permanently connected with the transformer and isolator outside zones 0, 1 & 2. 701.55 Electrical equipment installed within zone 1 must be at least IPX4 . 701.512.2 Only switches that are built into fixed Electrical equipment , the insulated pull cords of pull cord switches and switches of SELV circuits not exceeding 12v ac or 30v dc are permitted in zone 1. The SELV transformer and isolator must be outside zones 0, 1 & 2. No other switches or accessories are allowed. 701.512.3 p167 Light fittings are permitted in zone 1 and must be fixed and permanently connected. 701.55 Lighting fittings and switches installed within zone 2 must be at least IPX4. 701.512.2 Only switches that are built into fixed Electrical equipment , the insulated pull cords of pull cord switches, BS EN 61558-2-5 shaver units and socket outlets’ and switches of SELV circuits not exceeding 12v ac or 30v dc are permitted in zone 2. The SELV transformer and isolator must be outside zones 0, 1 & 2. No other switches or accessories are allowed. 701.512.3 For information on extra low voltage lighting see 559.11 For information on suspended lighting systems see 559.11.6 All final circuits must be wired separately from all other final circuits. 314.4

 

[amberleaf]

“ Fire Detection “ part P : for testers
All electrical equipment must be accessible for operation, inspection & testing , maintenance and repair. 132.12 *
NICEIC Domestic electrical Installation Certificates’ require that an additional 'Certificate of Design, Installation & Commissioning Of A Fire Detection & Alarm System Of Grade B, C, D, E or F In A Dwelling' must be provided for any fire detection systems including smoke alarms that are part of the installation. * Fire detection circuits must be supplied independently of other circuits and not protected by an RCD protecting multiple circuits. 560.7.1 * All literature supplied with fire detection equipment must be made available to the occupant of the dwelling. 560.7.12 * Fire detection cables, not including metal screened fire resistant cables, must be adequately segregated from cables supplying other circuits. 560.7.7 * BS-7671 does not provide detailed information for fire detection systems and is supplemented by BS 5839. p12 * The Building Regulations 1991 require all new and refurbished dwellings to be fitted with mains operated smoke alarms. The requirements for single family homes of not more than two storeys are that self-contained smoke alarms should be installed as follows : ** (i) at least one smoke alarm on each floor * (ii) within 7m of kitchens and living rooms and other areas where fires may start * (iii) within 3m of all bedroom doors * The smoke alarm must be installed in accordance with the manufacturers’ instructions, generally on ceilings and at least 300mm from any wall or ceiling light fitting ** The smoke alarms have to be interconnected, have a battery backup, and be permanently supplied from a separate way in the ccu , or supplied from a local lighting circuit that is regularly used. Please note this requirement conflicts with 560.7.1 Except for TT systems, the circuit supplying a smoke alarm should not be protected by an RCD. For TT systems the smoke alarm must be supplied from the fixed equipment section of the ccu, not through a 30mA RCD. ** The cables supplying each self-contained smoke alarm and supplying the interconnections between smoke alarms do not have to be fire retardant and need not be segregated. ** The Grade System - is the system of engineering, not the level of protection. * Grade F - one or more battery powered smoke and heat alarms. * Grade E - a system of interlinked mains powered smoke and heat alarms with NO battery back up. * Grade D - a system of interlinked mains powered smoke and heat alarms with battery back up. * Grade C - a system consisting of smoke detectors and sounders (which may be smoke alarms) connected to a common power supply, comprising of mains power and a stand by supply with central control equipment * Grade B - fire detection and alarm system comprising of fire detectors (other than smoke alarms), fire alarm sounders and control and indicating equipment to either BS EN 54-2 and power supply to BS EN 54-4, or to Annex C of BS 5839 pt6. * Grade A - fire detection incorporating control and indicating equipment to either BS EN 54-2 and power supply to BS EN 54-4 installed to BS 5839 : Pt 1 with some minor exceptions’. * Grade D is required for new, owner occupied buildings of up to three storeys, two storey rented properties, and existing owner occupied buildings of up to two storeys. Very large storeys may require a Grade B alarm system. * Levels Of Protection * LD1 - a system installed throughout the dwelling, incorporating detectors in all circulation spaces that form part of the escape routes from the dwelling and in all rooms and areas in which fires may start, other than toilets, bath and shower room ** LD2 - a system incorporating detectors in all circulation spaces that form part of the escape routes from the dwelling, and in all rooms or areas that present a high risk of fire. ** LD3 - a system incorporating detectors in all circulation spaces that form part of the escape routes from the dwelling.

 

[amberleaf]

“ FELV, PELV & SELV “

All items of current using equipment must be provided with a functional switching device. 537.5.1.3 *

FELV (functional extra low voltage) is an extra low voltage system (up to 50v ac, 120v dc) without all of the protective measures applied to PELV or SELV. p24 *

For more detailed information on FELV see 411.7, 612.4.4

PELV ( protective extra low voltage ) is an extra low voltage system ( up to 50v ac, 120v dc ) with a connection to earth. p27 *

For more detailed information on PELV see 414.1, 612.4.2 *

SELV ( separated extra low voltage ) is an extra low voltage system ( up to 50v ac, 120v dc ) with no connection to earth. p29 *

For more detailed information on SELV see 414.1, 612.4.1 *

Extra Low Voltage circuits should not be run in the same wiring system as 230v circuits unless all ELV cables and conductors are insulated for 230v or separated by an earthed metal screen. 528.1 *

All electrical equipment must be accessible for operation, inspection & testing , maintenance and repair. 132.12 *

“ Underfloor Heating “ All items of current using equipment must be provided with a functional switching device. 537.5.1.3 * Electric floor heating must not be protected by electrical separation. 701.753 * All circuits in a bath or shower room must be protected by a 30ma RCD. 701.411.3.3 * Electric floor heating in a bath or shower room must have a metal enclosure or sheath or a fine mesh metallic grid connected to the cpc of the supply circuit SELV supplies excluded ). 701.753 p/168 * All electrical equipment must be accessible for operation, inspection & testing, maintenance and repair. 132.12 * For more information on electric floor heating see 554.4, 753.1 *

“ Reference Methods “
PVC cables surface clipped - C
Armoured cables surface clipped - C
MICC cables surface clipped - C
PVC cables installed directly in an insulated wall - A
PVC cables installed in a building void - B
PVC cables in metal / plastic conduit or trunking surface mounted on a wall - B
PVC cables in metal / plastic conduit installed inside an insulated wall - A
PVC cables in metal / plastic conduit installed inside a building void - B
For more detailed information see Table 4A2 p261

 

[Mac]

Re: useful information

Another useful post there Mr Leaf.

Ill stick this one too, and i would respectfully ask members to refrain from posting here so that we can keep the thread clear.

Thanks.[/quote
Hi Jason,all these threads that amberleaf is posting,is there anyway that they can be compressed by the admin into a sort of folder or something.Just a ?.He is doing a great job

 

[amberleaf]

“ Basic & Fault Protection “
Basic Protection is protection against electric shock under normal operating conditions. , p20
Fault Protection is protection against electric shock with regard to a failure of basic insulation, p24
Exposed conductive parts of less than 50mm2 are exempt from fault protection. 410.3.9 *

Cables
Fire detection cables, not including metal screened fire resistant cables, must be adequately segregated from cables supplying other circuits. 560.7.7 * Cables must be suitably supported i.e. clipped or installed in conduit or trunking. 522.8.4 * Cables should be installed so as to avoid any possible damage caused by mechanical stress. 522.6.1 * Non sheathed cables (excluding protective conductors) must be installed in conduit, trunking or ducting. 521.10.1 * Cables must be not installed where they can be affected by heat from an external source. 522.2.1, 528.3.1 * Cables passing through a joist must be 50mm from the top or bottom of the joist or be sufficiently protected against damage. 522.6.5 * Where a cable is buried in a wall or partition at a depth of less than 50mm on either side it must be sufficiently mechanically protected against penetration OR Rcd protected AND installed either horizontally within150mm of the top of the wall or vertically within 150mm of the angle formed where two walls meet or run horizontally or vertically to an accessory, luminaire or ccu. 522.6.6 , 522.6.7. This applies to a cable in a partition constructed using metallic parts other than fixings irrespective of the cable depth. 522.6.8 * Surface run cables do not require RCD protection. OSG p22 * Cables buried underground must be armoured or have a metal sheath or be installed in a metal conduit or duct. Buried cables must be identified by cable covers or marking tape and buried at sufficient depth to avoid damage. 522.8.10 * Cables should not be run through a load bearing part of a building if the integrity of the load bearing part is compromised by the passage of the cable. 522.8.14 * Wherever possible cables should not be covered by thermal insulation. A cable covered by thermal insulation for more than 0.5m must have its current carrying capacity derated by a factor of 0.5. For more information see 523.7 *Where the sheath has been removed from a cable its cores must be enclosed within an accessory or enclosure of the appropriate standard. 526.9 * When a cable, conduit or trunking passes through a wall or floor it is necessary to seal the hole around the cable, conduit or trunking to the standard of the original wall or floor including any fire resistant/retardant properties. 527.2.1 * Switch lines must be marked brown at their terminations 514.3.1 , p343 * Telecommunication cables and power cables must not be run together. 528.2 * Main bonding conductors should not be supported by the service pipes they are connected to. 543.3.1 * Single core armoured cables must not be used in an a.c. circuit. 521.5.2 * Meter tails are part of the consumers installation and are to be provided by the installer. Meter tails must be sheathed and insulated or if insulated only must be enclosed in trunking or conduit. Meter tails must be 25mm. Where the meter tails are protected against fault current by the main fuse the installation method, maximum length and minimum cross sectional area must meet the distributors requirements. OSG p17 * Electricity cables must be spaced at least 25mm away from gas pipes up to 35mm and 50mm away from gas pipes over 35mm unless the pipes are PVC wrapped or a pane of insulating material is separating them. OSG p18 * PVC cables must be kept separated from expanded polystyrene materials. OSG p107 *

 

[amberleaf]

“ Extractor Fans “ Extractor fans must be provided with an easily accessible means of switching off the supply 132.15.2 * Electrical Equipment that may cause injury during mechanical maintenance i.e. fans, must be provided with a means to switch off the supply. 537.3.1.1 * All items of current using Equipment must be provided with a functional switching device. 537.5.1.3 * All Electrical Equipment must be accessible for operation, inspection & testing, maintenance and repair. 132.12 *
“ Immersion Heaters “ Extractor Fans An immersion heater must not be supplied by a ring final circuit. p362, 433.1.5 * An immersion heater must be connected to the supply by a double pole linked switch only. The use of a plug top and socket outlet is not permitted. 554.3.3 * An immersion heater must be provided with a thermal cut-out to prevent the water from boiling if the thermostat fails. 554.2.1 * All final circuits must be wired separately from all other final circuits. 314.4 * All Electrical Equipment must be accessible for operation, inspection & testing maintenance and repair. 132.12 *
The R1+R2 test sequence for radial final circuits Securely isolate the supply : Disconnect any bonding connections that could affect the test readings. : Make a temporary connection at the CCU between the phase and cpc of the circuit to be tested :. Using a low ohms continuity test meter measure the resistance between phase and cpc at each point on the circuit also confirming polarity. : The R1+R2 is the reading taken at the furthest point on the circuit. : Re-connect any bonding conductors disconnected for the test. : Remove the temporary connection at the CCU : .

“ Neutral Conductors “
In a TN-S or TN-C-S system the neutral conductor is not required to be switched or isolated when it is known that the supply neutral and earth conductors are connected. 537.1.2 ,537.2.1.1 * In a ccu the neutral conductors and cpc's should be connected to their respective terminals in the same order as the Phase conductors are connected to the mcb's. 514.1.2 * Only a linked circuit breaker that breaks all related line conductors can be used with an earthed Neutral conductor. 132.14.2 * It is assumed that where an installation is supplied in accordance with the Electricity Safety, Quality and Continuity Regulations 2002 the connection between the supply neutral and earth is permanent. 114.1 * The neutral conductor is considered to be a live conductor. * A neutral conductor must not be disconnected before a line conductor and must be reconnected before or at the same time as a line conductor. 431.3 * An Neutral conductor must not be independently fused or switched. 530.3.2 The conductors of a 230v circuit installed within a ferromagnetic enclosure must be arranged so that the phase conductor, neutral conductor and the appropriate cpc of each circuit are contained in the same enclosure. 521.5.2

“ Disconnection Times” under fault 230v final circuits in a TN systems not rated greater than 32A must disconnect within 0.4 seconds conditions. 411.3.2.2 * 230v final circuits in a TT systems not rated greater than 32A must disconnect within 0.2 seconds under fault conditions.If disconnection is made by a fuse or mcb and all extraneous conductive parts are connected to the main equipotential bonding then a disconnection time of 0.4 seconds is permitted. 411.3.2.2 * Under fault conditions in a TN systems circuits over 32A including distribution circuits must disconnect within 5 seconds. 411.3.2.3 * Under fault conditions in a TT systems circuits over 32A including distribution circuits must disconnect within 1 second. 411.3.2.4 *
all 17th stuff

“ Shower Circuits “ All items of current using equipment must be provided with a functional switching device. 537.5.1.3 * Electric showers are not to be installed in zone 0. 701.55 * All circuits in a bath or shower room must be protected by a 30ma RCD. p166 , 701.411.3.3 * All final circuits must be wired separately from all other final circuits. 314.4 * All electrical equipment must be accessible for operation, inspection & testing , maintenance and repair. 132.12 *

“ Lighting Circuits “ Where an installation has only one lighting circuit, the circuit may need to be divided into two circuits to minimize the danger that may arise in the event of a fault. 314.1 (iii) This is a !! Requirment !! for Domestic ← part , P, 17th *

“ Connections & Terminations “ Connections must not be subject to any mechanical stress or strain. 526.6 , 530.4.1 * All screw connections must be accessible 526.3 Through crimp connections do not have to be accessible. 526.3 * Stranded cables ends must be fitted with appropriate terminals or suitably treated. 526.8.1 * Every termination, connection or joint between live conductors including the Neutral Conductor must be made in a suitable Accessory or enclosure. 421.7, 526.5 * Live parts must be contained inside enclosures or behind barriers providing a degree of protection of at least IP2X or IPXXB . 416.2.1 * Switch Lines must be marked brown at their terminations. 514.3.1, p343 * A Neutral Conductor must not be disconnected before a line conductor and must be reconnected before or at the same time as a line conductor. 431.3 *

 

[amberleaf]

“ Cooker Circuits “ Unless specifically labelled or suitably identified, all 13A socket outlets must be 30ma RCD protected. 411.3.3 * All final circuits must be wired separately from all other final circuits. 314.4 * All items of current using equipment must be provided with a functional switching device. 537.5.1.3 * The Building Regulations require that accessories should not be mounted so that it is necessary to lean or reach over a cooker to operate them. * All electrical equipment must be accessible for operation, inspection & testing, maintenance and repair. 132.12 * Socket outlets must be spaced at least 150mm away from gas pipes unless there is a pane of non combustible insulating material separating them. OSG p18 * Cooker circuits rated between 16A and 50A may supply two or more cooking appliances installed in the same room. The cooker switch should be installed within 2m adjacent to the appliance(s). One cooker switch can be used to control more than one appliance. OSG p160 *
the R1 + R2 test Sequence for radial final circuits * Securely isolate the supply . Disconnect any bonding connections that could affect the test readings . Make a temporary connection at the CCU between the phase and cpc of the circuit to be tested. Using a low ohms continuity test meter measure the resistance between phase and cpc at each point on the circuit also confirming polarity. The R1+R2 is the reading taken at the furthest point on the circuit . Re-connect any bonding conductors disconnected for the test . Remove the temporary connection at the ccu .

“ Accessibility “ All electrical equipment must be accessible for operation, inspection & testing , maintenance and repair. 132.12 * All screw connections must be accessible. 526.3 Through crimp connections do not have to be accessible. 526.3 * “ Accessories “ All electrical equipment must be accessible for operation, inspection & testing , maintenance and repair. 132.12 * An accessory is an item of electrical equipment that does not use any current eg a switch or a socket-outlet. p20 * Every termination, connection or joint between live conductors including the neutral conductor must be made in a suitable accessory or enclosure. 421.7 , 526.5 * All accessories must be fitted to an appropriate mounting box. 530.4.2 * A wall mounted socket outlet must be mounted high enough above a floor or work surface to prevent damage to the flexible cord of a plug top. 553.1.6 * Unless specifically labelled or suitably identified, all 13A socket outlets must be 30ma RCD protected. 411.3.3 *
BS-7671 does not give specific heights for accessories. * “ part P “ The Building Regulations require the following : * accessories must be mounted between 450mm and 1200mm from the finished floor level in habitable rooms in new dwellings * the centre of a socket outlet should be a minimum of 150mm above the kitchen work surface * accessories must be installed a minimum of 300mm from the edge of cooker spaces, kitchen sinks and draining boards * accessories should not be mounted so that it is necessary to lean or reach over a cooker to operate them * accessories should be mounted on the building fabric and not on kitchen furniture * socket-outlets supplying washing machines and dishwashers should be installed so that water that may drip from plumbing equipment is unlikely to affect the socket-outlet or plug top *

“ Basic & Fault Protection “ Basic Protection is protection against electric shock under normal operating conditions. , p20 * Fault Protection is protection against electric shock with regard to a failure of basic insulation, p24 * Exposed conductive parts of less than 50mm2 are exempt from fault protection. 410.3.9 *

 

[amberleaf]

“ Prospective Fault Current “ At every relevant point of the installation the pfc must be determined by calculation, measurement or enquiry. 434.1 , 612.11 * Fuses and mcb's must have a breaking capacity greater than or equal to the maximum pfc at the point where the device is installed. 432.1 A lower breaking capacity is allowed if another fuse or mcb with the necessary breaking capacity is installed on the supply side and the energy let-through of both devices will not damage the fuse or mcb on the load side. 434.5.1 , 536.1 * “ Single Phase test Procedure “ Prospective Short Circuit Current ← ← Using a 3 lead PFC test instrument connect BOTH the neutral and earth leads to the neutral and the phase lead to the phase and take the measurement with the power on. * Prospective Fault Current. ← ← Using a 3 lead PFC test instrument connect the phase lead to the phase, the neutral lead to the neutral and the earth lead to earth and take the measurement with the power on. * The greater of the PFC and PSC values ↔ ( Ipf ) ↔ should be recorded on the Schedule of test Results

“ Underfloor Heating “ ● All items of current using equipment must be provided with a functional switching device. 537. 5.1. 3 : ● Electric floor heating must not be protected by electrical separation. 701.753 : part 7 , p – 168 ● All circuits in a bath or shower room must be protected by a 30ma RCD. 701.411. 3. 3 : ● Electric floor heating in a bath or shower room must have a metal enclosure or sheath or a fine mesh metallic grid connected to the CPC of the supply circuit SELV supplies excluded ). 701.735 , p-168 ● All electrical equipment must be accessible for operation, inspection & testing, maintenance and repair. 132.12. : ● For more information on electric floor heating see 554. 4. : 753.1. p-224 : more of this part 2 ps , fri , night more to follow this one “ amber going for a 6 pack

Ps , thanks Guys out of 300 !! ↔ It is nice to be nice ? Electricians did they teach you at Collage to say thank you ? My computer is on Vitamins , many thanks to the big BOSS , for putting up with me , thank you JASON , They Work as Well & and the Non paid staff that helps to run the SHOW . for the all Electricians I would to THANK YOU ALL AMBELEAF ,

“ Radial Final Circuits’ Supplying 13A Socket Outlets “ ● Unless specifically labelled or suitably identified, all 13A socket outlets must be 30mA RCD protected. 411. 3. 3. : ● A radial final circuit supplied by a 20A fuse or mcb must have live conductors with a minimum CSA of 2. 5mm a CPC with a minimum CSA of 1. 5mm and cover a floor area not greater than 50m2 . p-363 , 433.1 : ● A radial final circuit supplied by a 30a /32a fuse or mcb must have live conductors with a minimum CSA of 4.0mm2 a CPC with a minimum CSA of 1. 5mm and cover a floor area not greater than 75mS . An unfused spur supplying one single or double socket outlet can be run in 2. 5mm cable and may be connected to the fuse / mcb in the Consumer Unit . p-363 , 433.1 : ● The number of spurs supplied from a fused connection unit (a switched fused spur) and the size of the cable used to supply the spurs depends on the size of the fuse in the fused connection unit. p-363 , 433.1 :● All final circuits must be wired separately from all other final circuits. 314. 4 : ● All electrical equipment must be accessible for operation, Inspection & testing , maintenance and repair. 132.12 : ● Socket outlets must be spaced at least 150mm away from gas pipes unless there is a pane of non combustible insulating material separating them. OSG p-18 :

 

[amberleaf]

“ Incoming Supply “ 132.1.5.1 : ● A main switch must be provided to cut off the voltage to an installation. 132.15.1 : ● A double pole main switch or linked circuit breaker must be installed as close as possible to the incoming supply at the origin of the installation. 537.1.4 : p-241 : ● If an installation in the United Kingdom does not comply with Chapter 13 of BS-7671 the electricity supplier does not have to provide a supply to the property. p-241 : ● A TN-S supply has separate neutral and protective conductors. All the exposed conductive parts of the installation must be connected to the protective conductor at the main earthing terminal. p-30 , p-33 : ● A TN-C-S supply has a combined neutral and protective conductor. All the exposed conductive parts of the installation must be connected to the combined neutral and protective conductor at the main earthing terminal. This type of system is also known as PME ( protective multiple earthing ). p-30 , p-33 : ● PME submains are not permitted. 543. 4. 9 : ● 230v final circuits in a TN system not rated greater than 32A must disconnect within 0. 4 seconds under fault conditions. 411. 3. 2. 2 : ● Under fault conditions in a TN system, circuits over 32A including distribution circuits must disconnect within 5 seconds. 411. 3. 2. 3 : ● If the maximum Zs value for a circuit in a TN system cannot be met , the circuit may be protected by a 30mA RCD. 531. 3.1 : ● If the maximum Ze value for a TN system cannot be met, the installation may be protected by a 100mA RCD and treated as a TT system. 531. 3.1 : 411. 5.1 : 411. 5. 2 : 411. 5. 3 : ● A TT supply has the exposed conductive parts of the installation connected to an earth electrode which is separate from the earth of the supply. p-30 , p-34 : ● A single RCD protecting a TT system must be installed at the origin of the installation unless the part of the system between the origin and the RCD fulfils the requirements for protection by Class II equipment or equivalent insulation . 531. 4.1 : ● 230v final circuits in a TT system not rated greater than 32A must disconnect within 0. 2 seconds under fault conditions. If disconnection is made by a fuse or mcb and all extraneous conductive parts are connected to the main equipotential bonding then a disconnection time of 0. 4 seconds is permitted. 411. 3. 2. 2 : ● Under fault conditions in a TT system, circuits over 32A including distribution circuits must disconnect within 1 second. 411. 3. 2. 4 : ● For more information about TT systems see 411. 5. 2 : 612.8.1 : It is assumed that where an installation is supplied in accordance with the Electricity Safety, Quality and Continuity Regulations 2002 the connection between the supply neutral and earth is permanent. 114.1 : ● The incoming supply to a ↔ Domestic property ↔ is 230v with a permitted tolerance of + 10% / - 6% i.e. 216. 2v - 253. 0v . p-242 : OSG , P-17 : ● Meter tails are part of the consumers installation and are to be provided by the installer. Meter tails must be sheathed and insulated or if insulated only must be enclosed in trunking or conduit. Meter tails must be 25mm2. Where the meter tails are protected against fault current by the main fuse the installation method, maximum length and minimum cross sectional area must meet the distributors requirements. OSG , P-17 : 521.10.1 : ● Meter tails 521.10.1 : 530. 3. 4 : 434.3 : 521.14. 3 : for Domestic part p , ←
“ Distribution Circuits “ ● A distribution circuit is the circuit that connects the incoming supply to the CCU i.e. meter tails. When a distribution circuit supplies an installation remote from the incoming supply it is sometimes referred to as a sub main. P-23 : ● Under fault conditions in a TN system, circuits over 32A including distribution circuits must Disconnect within 5 seconds. 411. 3. 2. 3 : ● Under fault conditions in a TT system, circuits over 32A including distribution circuits must Disconnect within 1 second. 411. 3. 2. 4 :

“Insulation “ Resistance ● SELV & PELV circuits must have a minimum insulation resistance of 0. 5MΩ when tested at 250v dc. with all current using equipment disconnected. 612. 3. 2 : ● Circuits up to 500v must have a minimum insulation resistance of 1.0MΩ when tested at 500v dc with all current using equipment disconnected. 612. 3. 2 : ● These values are considered satisfactory. 612. 3. 2 : ● These values do not apply to fire detection systems. 612. 3. 2 : ← ← ← read this one , ● The insulation resistance must be measured between live conductors (including the neutral ) and between live conductors and the cpc connected to earth. 612. 3. 1 : ● If the circuit contains devices that may be damaged by the test, only a test between the live conductors connected together and the cpc connected to earth is necessary. 612. 3. 3 : ← ← ← read this one

 

[Sparky Bones]

I am a new 'sparky' and my training has gone well, but I need a bit of help passing 2330-203
I am trying to find our some old papers etc so that I can get my mark up. I got 98% on the health and safety but only 53% on the electrical principles.

Can anyone send me some old papers so I can get this mark up?
Thanks

 

[Mac]

I am a new 'sparky' and my training has gone well, but I need a bit of help passing 2330-203
I am trying to find our some old papers etc so that I can get my mark up. I got 98% on the health and safety but only 53% on the electrical principles.

Can anyone send me some old papers so I can get this mark up?
Thanks

Hi and welcome to the forumThere maybe someone along later on to help you

 

[amberleaf]

● Earthing & Equipotential Bonding ● ● Before an addition or alteration can be made to an existing installation it must be ascertained that the earthing and bonding arrangements comply with the current version of BS 7671 and any existing equipment including the incoming supply is adequate for the proposed addition or alteration. 131.8 : ● Every installation must be provided with a main earthing terminal. 542.4.1 : ● The main earthing terminal, all bonding conductor connections and connections to an earth electrode must be permanently labelled 'Safety Electrical Connection - Do Not Remove'. 514.13. 1 , : ● Every joint and connection must be accessible. 543.3.3 , 526. 3 : ● All circuits’ must have a cpc that is terminated at each wiring point and at each accessory . 411.3.1.1 : ● Rigid metal conduit and the metal sheath or armour of a cable can be used as a protective conductor. 543.2.2 , 543.2. 5 : ● Where rigid metal conduit or the metal sheath or armour of a cable is used as a protective conductor, a separate protective conductor must connect the earthing terminal of any accessories to the appropriate metal back box. 543.2.7 , 543.7.2.1 : All joints in metal conduit must be continuous. 543.3.6 : ● The cpc of flat cables must be sleeved when the cable sheath has been removed. 543.3.2 : ● Protective conductors must be identified by the colours green & yellow. 514.4.2 The single colour green is not permitted. 514.4.5 : ● In most domestic installations switches are not to be used with a protective conductor. 543.3.4 : ● All exposed conductive parts of a TN installation must be connected to the main earthing terminal. 411.4.2 ● All extraneous conductive parts in an installation must be connected to the main earthing terminal by main protective bonding conductors. This applies to the metallic sheath of a telecommunication cable where permission from the owner of the cable must be obtained. 411.3.1.2 : ● Main Earthing Conductor ● The minimum csa of the main earthing conductor must be determined by the adiabatic equation or selected from Table 54.7 543.1.1. If the adiabatic equation is used, the minimum csa of the main earthing conductor must be 6mm 544.1.1. Table 54.7 suggests a 16mm main earthing conductor for phase conductors with a csa of up to 35mm. : ● The csa of the main earthing conductor where PME conditions apply should be not less than that for a main protective bonding conductor (10mm ) for the same installation 544.1.1. Invariably the electricity supplier will provide a 16mm main earthing conductor for a PME supply in a domestic property. : ● Main Protective Bonding Conductors’ ● ● For TN-S or TT systems the csa of main protective bonding conductors must be a minimum of 6mm and not be less than half the csa of the main earthing conductor. 544.1.1 : ● For a PME system the csa of the main bonding conductors must not be less than that given in Table 54.8 i.e. a 10mm protective bonding conductor for a neutral conductor of 35mm or less. 544.1.1 : ● For a service pipe, the main bonding conductor should be connected as near as possible to the point where the service enters the building. The connection must be before any branched pipe work and on the consumers side of any meter. If possible the connection should be made within 600mm of the meter outlet. Where the meter is outside, the bonding connection should be made at the point of entry of the service into the building. 544.1.2 : ● Main bonding conductors should not be supported by the service pipes they are connected to. 543.3.1 : ● Where a main bonding conductor loops in and out to connect to an extraneous conductive parts the conductor should be unbroken at the connection. 528.3.3 : ● It is not necessary to run a main protective bonding conductor to an incoming service where the incoming service pipe and the consumers pipe work are both made of plastic. If the incoming service pipe is made of plastic and the consumers pipe work is made of metal it is recommended to main bond any metal paperwork. OSG p29 : ● Supplementary Bonding Conductors ● ● Supplementary bonding is not required in a bath or shower room if all the extraneous conductive parts of the installation are connected to the main equipotential bonding. P166 , 701.415.2 : ● It is not generally required to supplementary bond the following : kitchen pipes, sinks, draining boards, metallic kitchen furniture, boiler pipes, metallic parts supplied by plastic pipes or metal pipes to hand basins or wc's ( excluding metal waste pipes in contact with earth ). OSG p31 : ● Earth Electrodes ● → All of the following can be used as earth electrodes : ← Earth rods or pipes ↔ Earth tapes or wires ↔ Earth plates ↔ Underground structural metalwork embedded in foundations ↔ Welded metal reinforcement of concrete embedded in the Earth (excluding pre stressed concrete ↔ Lead sheaths & metal cables coverings provided the following conditions are met ↔ A - the cable covering must be in effective contact with Earth ↔ B - the permission of the cable owner must be obtained ↔ C - the owner of the cable must be able to inform the owner of the installation of any changes to the cable which may affect it suitability as an earth electrode 542.2.1, 542.2.5, ↔ A metal gas or water pipe must not be used as an earth electrode. 542.2.4 :

 

[amberleaf]

● Cannot be used as a source for a Selv or Pelv System , AUTO-Transformers ← ♫♫♫
What is the MAIN danger with AUTO-Transformers
They can Introduce the Primary voltage onto the Secondary Output terminals during short-circuit

→ CARE MUST BE TAKEN AS DEATH, INJURY AND/OR DAMAGE to equipment may result ←
● 230v ↔ 24v ↔ 230v ●

● New ↔ European Legislation Requires ↔ ALL fire extinguishers to be the same colour.
the main body of all fire Extinguishers is ↔ Red ← ( ? they did something right ,

● Some Revision A Residual Current Device is used to provide Supplementary protection against direct contact and has
A residual operating current of 30mA , if a test current of 15mA is applied between phase & earth
At the output terminals of the device it should :
Not operate within ( 2 sec ) HOW TO REMMBER 30mA ÷ 15mA = 2s

City & Guilds 2392-10

The Purpose of an Electrical Installation Certificate is to provide a formal Assurance from those Responsible
For the Design , Construction , and Inspection and Testing of new Installation work ) including Alterations’ and additions to Existing Installations ) that the Work Complies with National Standard for the Safety of
Electrical Installations , and is therefore Safe to put into Service ,
“ Initial Verification “ The wiring regulations are clear about the requirements of inspection and Testing. The Requirement to carry out an 'Initial Verification' for all New Installations, whatever the size of the work carried out, is included in the fundamental principles of the wiring regulations in regulation 134.2.1.

 

[amberleaf]

Bell Circuits : ● All electrical equipment must be accessible for operation, inspection & testing , maintenance and repair. 132.12 : ● Extra Low Voltage circuits should not be run in the same wiring system as 230v circuits unless all ELV cables and conductors are insulated for 230v or separated by an earthed metal screen. 528.1 : ● All items of current using equipment must be provided with a functional switching device. 537.5.1.3. : ● Eddy Currents : ● To avoid eddy currents, conductors of an ac circuit should not be installed in separate steel conduits. 521.5.2 : The conductors of a 230v circuit installed within a ferromagnetic enclosure must be arranged so that the phase conductor, neutral conductor and the appropriate cpc of each circuit are contained in the same enclosure. 521.5.2 : ● Single core armoured cables must not be used in an a.c. circuit. 521.5.2 : ● Telecommunication Circuits : BS 7671 does not provide detailed information on telecommunication circuits and is supplemented by BS 6701. p12 : ● All extraneous conductive parts in an installation must be connected to the main earthing terminals by main protective bonding conductors. This applies to the metallic sheath of a telecommunication cable where permission from the owner of the cable must be obtained. 411.3.1.2 : ● Telecommunication cables and power cables must not be run together. 528.2 : Extra Low Voltage circuits should not be run in the same wiring system as 230v circuits unless all ELV cables and conductors are insulated for 230v or separated by an earthed metal screen. 528.1 :

 

[amberleaf]

“ Operation less than “

Type No , 100millisecnds ( Instantaneous ) 433.1 States that “ Provided an Overload Protective Device .
(B) Between 3 and 5 times rated current Protection against Short-Circuit
(C) Between 5 and 10 times rated current
(D) Between 10 and 20 times rated current

Every Circuit shall be designed so that a small overload of long duration is unlikely to occur

selv & felv

SELV and FELV are two totally different beasts .

110 V single phase, fed from a transformer, often with an earthed centre-tapped secondary winding, to feed transportable tools and equipment, such as floodlighting, with a load of up to 2 kW. This supply ensures that the voltage to earth should never exceed 55 V (see The primary winding of the transformer must be RCD-protected unless the equipment fed is to be used indoors.

Supplies will normally be obtained from the Electricity Supply Company. Where a site is remote, so that a generator must be used (IT supply system) special protective requirements apply which are beyond the scope of this Guide, and the advice of a qualified electrical engineer must be sought. Attention is drawn to BS 7375: 1966 Code of Practice for the distribution of electricity on construction and building sites.

The equipment used must be suitable for the particular supply to which it is connected, and for the duty it will meet on site. Where more than one voltage is in use, plugs and sockets must be non interchangeable to prevent misconnection. Six levels of voltage are recognised for a construction site installation. They are:

25V single-phase SELV for portable hand-lamps in damp and confined situations,
50V single-phase, centre-point earthed for hand lamps in damp and confined situations,
400V three phase, for use with fixed or transportable equipment with a load of more than 3750 Watts,

230V single phase, for site buildings and fixed lighting ----
110V three phase, for transportable equipment with a load up to 3750 Watts, and

110V single phase, fed from a transformer, often with an earthed centre-tapped secondary winding, to feed transportable tools and equipment, such as floodlighting, with a load of up to 2 kW. This supply ensures that the voltage to earth should never exceed 55 V (see {Fig 7.5}). The primary winding of the transformer must be RCD-protected unless the equipment fed is to be used indoors.

“ Safety Service “ Chapter 56 p /151

560.6.7
1 ,Where a generating set is used as an additional source of supply in parallel with others sources ,
Protection shall remain effective in all situations against overcurrent and ←

● Answer , the time it takes for safety source to supply the power to the safety service ,
After the loss of the main power supply ,

2 , Regarding Auxiliary supplies to Safety Services , the maximum changeover time refers to : ←
● Answer , the time it takes for the Safety Source to Supply the power to Safety Service , after the loss of
The main power Supply ,
“ This is what the 17th is asking you “

537.5

537.5.2
Functional switching devices : ● generally required to be capable of switching the Load “ on and off “
537.5.1.4
Definition Functional Switching ●

“ Equipment may be used controlled either manually or automatically “

( 1 ) A Time switch is an example of an automatically-operated functional switch ●
( 2 ) A switch in a socket-outlet ●
( 3 ) A contactor switching the supply to start and stop an electric motor ●
( 4 ) A push buttons used to control a contactor or relay ●
( 5 ) A thermostat used to switch an immersion heater “ on “ and “ off ●
( 6 ) A pressure switch or level switch used a pump on and off ●
( 7 ) A Lighting switches and dimmers ●

( Functional switching devices do not necessarily have contacts that open & close
Opening contacts are not essential ,

537.5.2.1.
Functional switching devices shall be suitable for the most onerous duty they are intended to perform ,
● Should be selected to have a utilization category Appropriate to the Type of load being Switched , ←

537.5.2.3.
Off-Load isolators ( disconnectors ) fuses and links shall not be used for Functional Switching ,
● NOT to be used for this Purpose , C/G ← ←

 

[amberleaf]

C/G are bring out a New Certificate , for Confined Spaces , → → on September 2009 ←←

“ Earthing & Cable Things “
● When two Bonding Conductors of Equal Length are Connected in Parallel the Resistance would , ( Halve ) ←
● The Resistance of a Bonding Conductor will Increase if , ( the Length Increases ) ←
● An Earth Loop Impedance Tester should only allow current to flow for , ( 40mS ) ←
● A Reference Method Indicates , ( The Instillation Method ) ←
● the Value will Decrease as we move Farther away from the Intake Position ( Resistance Increases with Length )
● A final circuit is the wiring between the ( Distribution Board and Current using Equipment ) ←
● The Effects of Creating a Ring Final Circuit would be that the Overall Resistance of the Conductors would ( Decrease ) ←
● When Applying the rule of thumb method , the value of Prospective Short-Circuit Current for a 3 Phase Supply should be ,
( Twice the Single Phase Value ) ←

With many thanks I would Like to say thank you for a First Class Forum . Amberleaf
You professionalism is second to nun ,

 

[amberleaf]

● if you Double the Length of Wire ( you will Double the Resistance of the Wire ) ←
● if you Double the Cross-Sectional Area of a Wire you will Cut its Resistance in ( Half ) ←
● The Resistance in Ohms , of a Conductor , ( Increases with Increase of Cable Length ) ←


Regulations 434.1 / 612.11

● Require that the Prospective Short Circuit Current and the Prospective Earth Fault Current are Determined ,
Once Determined , The Highest Value Must be Record , ( PSCC ) ( PFC ) Ia / Ief

● A Prospective Short-Circuit Current is the Maximum Current that Could flow Between ● Phase and Neutral Single–Phase Supply ,

● A Prospective Earth Fault Current is the Maximum Current that Could Between Live Conductors and Earth ,

● The Higher of these Value is know as Prospective Fault Current ,

● the High Prospective Fault Current will be at the Origin of the Installation and must be Measured as Close to the Meter Position
As Possible , Usually at the Main Switch for the Installation , it is Measured between Phase and Neutral ,

● Enquiry to the Suppler ,
● Calculation ,
● Measurement ,

● Enquiry ,
Phone Call to the Electricity Supplier of the Installation ,
That will tell you the Maximum ( PFC ) Usually this is a Lot Higher than the Value will Actually be ,

● Calculation ,
The ( PFC ) can Only be Calculated on a ( TN-C-S Systems ,
The Neutral of the Supply is Used as a Protective Earth & Neutral ( PEN ) Conductor , ≈≈≈≈≈≈

When the Earth Fault Loop Impedance is Measured ,
The Value Measured is in Ohms ,
To Convert this Value to Prospective Short-Circuit-Current ( PSCC ) we must Use the following Equation ,

V Ze > Measured – 0.28Ω 230 ÷ 0.28 = 821A
( PSCC ) = ------ = I
Ze

● Measurement ( kA )
This is Carried out Using a Prospective Fault Current Tester ,
Measurement of ( PFC ) is taken as Close to Supply intake as Possible ,

● Measurement ( Ohms )
Measurement Value , 0.08Ω

Uoc - 230v
230v
( PSCC ) = -- ÷ -- = 2875A
0.08 Ω

Measurement of ( PFC ) if taken Close to the Supply intake as Possible ,
All Protective Devices fitted in the Installation have a Short Circuit Capacity
That is Higher than the Measured Value , ( 432.3 will be Satisfied ,

( Jason what is my P/Qs please , Amberlaef , can you send me a Email , 11/6/09 )

 

[amberleaf]

Schedule of Inspections , page 340 ← ( 1 ) ( 2 ) in the making ,

Methods of Protection against Electric shock

Both basic & fault protection :

(i) Selv , ( Correctly Installed and used , Note 1 ●
(ii) Pelv , ( Same as Selv but with Earth , ←
(iii) Double Insulation , ( Protected by an layer of Insulation look for symbol , Note 2 ●
(iv) Reinforced insulation , ( Single layer of very strong insulation , Note 2 ●

Basic Protection , Note 3 ●

(i) Insulation of live parts ( All live parts Insulated where required , ←
(ii) Barriers or enclosures ( Correct IP codes . Check Definitions , ←
(iii) Obstacles ( Limited use Not Domestic , Note 4 ●
(iv) Placing out of reach ( 410-3-5 Note 5 ●

Fault Protection

(i) Automatic Disconnection of Supply ,

● Presence of Earthing Conductor , ( At intake , ←
● Presence of Circuit Protective Conductors , ( CPC in all Circuits , ←
● Presence of Protective Bonding Conductors’ , ( Water, Gas, Oil, etc , ←
● Presence of Supplementary Bonding Conductors , ( Mainly Bathrooms , ←
● Presence of Earthing Arrangements for Combined , ( Rare , ←
Protective and Functional Purposes ,

● Presence of Adequate Arrangement for ( Generators ←
Alternative Source(s) where Applicable

● Felv , ( Not Compliant with Selv , ← ●
● Choice and Setting of Protective and Monitoring ( Correct MCB or Fuse , ←
Devices ( for Fault and / or Overcurrrent Protection )

(ii) Non-Conducting Location , Note 6 ●
● Absence of Protective Conductors , ( Operating Theatres , ←

(iii) Earth-Free Local Equipotential Bonding , Note 6 ●
● Presence of Earth-Free Local Equipotential Bonding , ( Not Domestic ,

(iv) Electrical Separation , Note 7 ● ( Isolating Transformers , ← ●
Provided for one item of Current-Using Equipment ,

● Provided for More than One item of Current-Using Equipment ,

Additional Protection ,

● Presence of Residual Current Devices , ( 415 -1 ←
● Presence of Supplementary Bonding Conductors , ( 415-2 ←




(1) SELV - an Extra Low Voltage Systems which is Electrically Separated
From Earth and from Other Systems in Such a Way that a Single – Fault Cannot give Rise to the Risk of Electric Shock ,
The Particular Requirement of Regulations must be Checked ( see Section 414 )

(2) Double or Reinforced Insulation , Not Suitable for Domestic or Similar Installations if it is the Sole Protective Measure ( see 412-1-3 )

(3) Basic Protection – will Include Measurement of Distances where Appropriate ,

(4 ) Obstacles – only Adopted in Special Circumstances ( see 417-3 )

(5) Placing out of Reach – only Adopted in Special Circumstances ( see 417-3

(6) Non- Conducting Locations and Earth-Free Local Equipotential Bonding –
These are Not Recognised for General Application ,
May Only be used where the Installation is Controlled / Under the Supervision of Skilled or Instructed Persons ( see Section 418 )

(7) Electrical Separation – the Particular Requirements of the Regulations must be Checked if a Single item of Current-using Equipment is
Supplied from a Single Source , see Section 413, if More than One the Installation must be Controlled / under the Supervision of Skilled or
Instructed Persons , See Also Regulations 418-3




● IMD / 411.6.3 , Installed in a Location where Unskilled Personnel have Access shall be Designed or Installed in such a Way ,
Shall NOT be Possible to Modify the Settings , Except by Use of a Key, or a Tool or a Password ,
● RCM / Doesn’t Trip , Gives Warning of Problems , Used with IT Systems ,
● RCDs Do Not Protect against Overloads / Do Not Protect against Short Currents , “ Definitions “ ● RCD Operation, Current Balance ) Earth Fault Current Only , “ Definitions “
● RCCBs Residual Current Circuit-Breaker with Integral Overcurrent Protection , ( Not for Overload Short-Circuit ) “ Definitions “
● RCBOs Minimise Inconvenience in the Event of a Fault / Short-Circuit , Overcurrent Protection , “ Definitions “
● RCBOs Both Overload Short-Circuit Protection / Overcurrent Protection : “ Definitions “

● Overload Current , Overcurrent Occurring in a Circuit which is Electrically Sound , 431.1.1 / 430.3 ,
● Preliminary Design ( In ≥ Ib ) 433 , ● Overcurrents Requirements’ ( In ≥ Ib ) 434 , Domestic Installation ,
Fault Currents’ ( Earth Faults or Shorts-Circuits )
Overload Currents , ( Overcurrents may be ! ,
Cables must be-Able to Carry Overcurrents Without Damage , (Iz) 411 ,
411 , Fault / Protection is Provided by ( i ) ( ii ) , “ADS”
( iii ) , Protection by One Device ,
Three Methods’ for Achieving “ Fault-Protection “ 131.2.2 , ( i ) ( ii ) , ( iii ) ,
Protection Against Electric Shock to be Provided by Basic & Fault Protection , ( one Method Common to Both )

 

[amberleaf]

Functional Testing : all 3 is the same Meaning ,

RCDs used for “ Earth Fault “ Currents Only ( 30mA RCD is installed to give Added Protection Against “ Basic Protection “ i.e. , Touching Live Parts )
Breaker should Trip 0ut in 40mS at a Residual Operating Current of x5 , 150mS ,

● 30mA RCD is Used to Provide Supplementary Protection against Electric Shock .
When tested with a Current of 150mA , operating time should not exceed , 40mS

( 30mA RCD is Installed to give Added Protection )
Residual Operating Current of x5 , 150mS , 40mS

Schedule of Inspections , page 340 ← ( 2 )

Prevention of Mutual Detrimental Influence
● (a) Proximity of Non – Electrical Services and Other Influences , ( Cables tied to Pipes ? Hot Pipes near Cables ) ←

● (b) Segregation of Band I & Band II Circuits or use of Band II Insulation , ( Low and Extra Low Voltages Segregated ) ←

● (c) Segregation of Safety Circuits , ( Emergency Lighting and Fire Alarms Cables Not in Same Trunking ) ←

Identification ,

● (a) Presence of Diagrams , Instructions , Circuit Charts and Similar Information , ( At Mains ) ← “ Distribution Board Schedule “ Domestic ,

● (b) Presence of Danger Notices and Other Warning Notices , ( Bonding , Isolation ) ← 514-10

● (c) Labelling of Protective Devices , Switches & Terminals , ( What do they do ? ) ←

● (d) Identification of Conductors , ( Sleeving and Cores ) ← 514-4-2 / table, 51

Cables & Conductors

● Selection of Conductors for Current-Carrying Capacity & Voltage Drop , ( Measure or Calculate ) ←

● Erection Methods , ( Installed to BS-7671 ) ←

● Routing of Cables in Prescribed Zones , ( On-Site-Guide ) ←

● Cables Incorporating Earthed Armour or Sheath , or Run
Within An Earthed Wiring System , or Otherwise Adequately
Protected Against Nails , Screws & the Like , ( 522-6 ) ←

● Additional Protection Provided by 30mA RCD for Cables in
Concealed Walls ( where Required in Premises not Under the
Supervision of a Skilled or Instructed Person ) ( 411-3-3 / 522-6 ) ←

● Connection of Conductors , ( Tightn no Copper Showing ) ←

● Presence of Fire Barriers , Suitable Seals & Protection Against Thermal Effects , ( 527-1 ) ←

General

● Presence and Correct Location of Appropriate Devices for Isolation & Switching , ( Isolators in Place ) ←

● Adequacy of Access to Switchgear and Other Equipment , ( Safe Access ) ←

● Particular Protective Measures for Special Installations and Locations , ( Special Locations Part 7 What is Required ) ←

● Connection of single-Pole Device for Protection or Switching in ( Polarity Visual Check ) ←
Line Conductors Only

● Correct Connection of Accessories and Equipment ( As Instructions’ ) ←

● Presence of Undervoltage Protective Devices ( Motor Starters ) ←

● Selection of Equipment and Protective Measures Appropriate to External Influences , ( Water , Dust Proof ) ←

● Selection of Appropriate Functional Switching Devices , ( Isolator Not used as a Switch ) ←

Thank you , George is on the 6/Pack , Sorry did I mean 12 pack tonight , 21 Again ,

PS / Ill need to stop Studying or ILL end up a Masters Decree , Sorry about this Jason , can Keep a Good man Down Amberleaf ,


● A Good Insulator has Low Conductivity and ( High Resistivity ) ←

● 100mA RCD protecting a TT installation tested at ½ : ( Should Not Operate ) ←

● Testing a Ring Final Circuit Protected by a BS-EN 61009 30mA RCBO with an “ RCD tester “ at x5, should disconnect ( within 40mS ) ←

● An RCD when tested at 500% ( x5 times ) of its tripping rating should : ( trip within 40mS )

● When Tested a Ring Final Circuit Protected by 200mS BS-EN 61009 - 30mA RCBO

● Specification for Socket-Outlets Incorporating Residual Current Device ( S.R.C.D. s )
When tested at 100% an RCD Protecting Socket-Outlet to BS-7288 should Operate Within , 200mS
with an “ RCD Tester “ At x5 , should Disconnect ( Within 40mS )
BS-7288 – IP56 ↔ if Used Out Doors ,

● RCD , What is the Result of a very Low Total Fault Loop Impedance
( Very High Fault Current and Quick Disconnection ) ←

● Note that for RCD Protected Socket-Outlet to BS-7671 the RCD should Operate 200mS at I∆n ←←

● RCBOs to 61008 / 61009 should Operate Within 300mS
RCBOs should Operate , at Full I∆n they Operate within 300mS , and at x5 they should Operate within 40mS ,

● RCD Operating time at I∆n Must be Less than 300mS BS-EN Type ←←←← or 200mS if BS - ←←←←

● RCD Operating time at 5 I∆n Only Required for RCDs Rated at 30mA or Less ,
When used for “ Supplementary Protection “ against Direct Contact , Never Use RCD above 30mA ,

● Insulation Résistance , Values Required for between Live Conductors , and Live Conductors and Earth , if Measured Value is below 2MΩ ↔ Further Investigations is Required
● Damp Getting into a Cable “ Pyo ” can Lead ( Insulation Failure ) ←
( This can Lead to ” Nuisance Tripping ” of the Protective Device )
>> Never leave Pyo Exposed to Damp ‹‹‹ if you Do you’ll lose more the a Meter Cable and Look a right Pratt , PS , Electrician doing Handstands’

● When Carrying out an Insulation Resistance Test between Conductors on a One-Way Lighting Circuit , have the
( Remember Switch Closed and Lamp Out ) ↔ ( Two –Way / One Switch Closed / and the Other Opened )

● It is a Good idea when Performing an Insulation Resistance Test on a Large Installation to Subdivide Circuits’ ,
( To avoid False Readings from Parallel Resistance’s ) ←

● To Ensure the Protective Device Operates Requires a ( Low Fault Loop Impedance Path with a Resultant High Earth Fault Current Flow ) ←

● When a Periodic Inspection should be Carried Out are ,
When a Property is being Prepared to be Let ,
When a Property is being Sold where Tenets have Lived in Property
( Periodic Inspection Reports Should Only be Used for Reporting on the Condition of an Existing Installation , p-339
BS-7671 - p-339 – Notes (1)

 

[amberleaf]

Overcurrent Protective Device for the Supply ,
Usually this will be a BS-88 or BS-1361 Cartridge Fuse and it will Normally be Marked on the Supply Cut Out
If it is Not , then it Should be Found by Asking the Supply Provider , ↔ PS , phones out Chaps ,
Domestic Electricians ↔ 100A , type IIb – BS-1361 415V a.c , ←←←
Type of Overcurrent Protective Device ,
BS- or BS-EN , enter Number ,

BS-88-2 50kA
BS-1361 16kA / 33kA
Type 1 rated Current 5 to 45A ,
Type 1 Fuses to BS 1361 / 41.2 ( Zs )
BS-1361 Type 1 Distribution boards , Replaced by Consumers ,
Type 11 rated 60A to 100A
Type 11 BS- 1362 , Primarily intended , Distributors Cut-Out Fuses Service Units Domestic Similar Premises ,

Fuses BS- 1362 , / 41.2 ( Zs ) cartridge Fuse , Regs P-229
Fuses BS- 1363 , / Pat Testing Insulation Resistance Test 1MΩ / 500v Domestic , Class 1 Equipment , Regs P-229 ,

Nature of Supply Boundary’s ,
This can be Gained by Enquiry or Measurement ,
U. is Phase to Phase / Phase
Uo Phase to Earth ,

Short Circuit Capacity ,
Short Circuit Capacity of the Device
It may be marked on the Device , if not ( OSG. 7.4 ) – p-57

Whatever it is , it must be at Least → EQUAL ← to the ( PFC ) ←←←

For Domestic Electricians ,

Method of Protection against Electric Shock ,
Both Basic & Fault Protection
SELV & PELV ( 414.1 / 414.4 ( SELV Source that a Shock to Earth Cannot Occur for a Single Fault , ←←←
Protection Against Both Direct & Indirect Contact is Afforded by Using SELV , ←←←

Basic Protection
Applies to all Electrical Installations , ( 412.2 ↔ Band 1 / 416.1

Barriers or Enclosures ,
Applies to all Electrical Installations , All Enclosures must Comply with 412.2.2.1
Horizontal top Surfaces to Enclosures IP4X sides ,
Front and Bottom IP2X or IPXXB ,

Blanks fitted to Distribution Units
Access to Live Parts by Use of key or Tool ,
Secondary barriers within Enclosures Only Removable with the Use of key or Tool ,

Double & Reinforced Insulation , ( Regulations 412.1

IMDs
411.6.3 the following Monitoring Devices & Protective Devices may be Used , 538.1.3 / 531.6.1

Placing Out of Reach
Applies to Overhead Lines , ( Regulations 410.3.5 & 417.1

Fault Protection
Automatic Disconnection of Supply
Requirements for Fault Protection are set Out in ( Regulations 411.3

Presence of Earthing Conductor
Protective Earthing must be present ( Regulations 411.3.1.1

Presence of Circuit Protective Conductor
Each Circuit must have a CPC which must be Tested for Continuity ,

Presence of Protective Bonding Conductors
Extraneous Parts of the Installation must be Connected to the Main Earthing Terminal ( MET ) Regulations 411.3.1.2

Presence of Supplementary Protective Bonding Conductors ( where Required )
Regulations 415.2 This is Used where Additional Protection Against Electric Shock , can be used in some Special Locations ,

FELV
41.7.1. This is Used where Extra Low Voltage is Required but it is not Necessary to Comply with the
Regulations of SELV or PELV ,

Choice and Setting of Protective and Monitoring Devices for Protection
Against Indirect Contact and / or Overcurrent ,
Correct Size and Type of Protective Devices / RCD are suitable for use to which they are being put,
Monitoring Devices not used for Domestic Situations ,
IT supply Systems / some Construction Sites ,

Non-Conducting Locations
Used in Special Areas / Hospitals / Laboratories
Installation Requires Specialist Knowledge ( Regulations 418.1 )

Earth Free Local Equipotential Bonding
Found in Electronic / Electronic / Electrical Repair Workshops ( Regulations 418.2. )

Electrical Separation
Used in Bathrooms’ for Saver Sockets , The Secondary Supply is Separated from Earth ,
This does Not include SELV ( Regulations 413.1

Where more than One item of Equipment is Supplied from a Single Source ,
( Regulations 418.3 Should be Applied ,

Prevention of Mutual Detrimental Influence
Proximity of Non Electrical Services and Other Influence’s
( Regulations 515.1 / 2 and Sections 522 and 528.3 Items should be inspected to Ensure that the Electrical System cannot cause
harm to Non - Electrical Services ,and that the Electrical System is Unaffected by External Influences ,
Cables tied to Pipes or Next to Central Heating Pipes ,

Segregation of Band I & Band II Circuits or Band II Insulation Used
( Regulations 515.2 Sec 528.1 Low Voltage Cables not in same Enclosures as Extra Low Voltage Cables
TV , Aerials , Door Bells & Telephone Cables ,

“ Domestic “ Electrician

● An Enclosure that would prevent Ingress by British Standards human Finger would have an IP rating of , ( IP2X ) ←

● the Top part of a Distribution Board must Conform to ( IP4X ) ← 416.2.2

● The Sides of a Distribution Board must Conform to ( IP2X ) ← 416.2.4

● A Code IP4X assigned to a Electrical Item would Prevent Ingress from ( Wire or Solid Objects Greater than 1mm in Diameter ) ←

● Protection Against Direct Contact by Barrier or an Enclosure : 416.2
● Provided During Erection 612. 4. 5
● IP2X ( IPXXB ) Protection Required for all Enclosures from , Side & Bottom ,
● IP2X ( IPXXB ) = No Solid Objects larger than 12mm Diameter and 80mm long ,
● Top Distribution Board ↔ IP4X Protection required for all enclosures from above ( max 1mm – dia )
● 10N Finger pressure Max ,
“ Test Finger ” Must be to BS-3042 Specification

● Guidance Note 1 , Selection & Erection ( Guidance Notes )
● Guidance Note 2 , Isolation & Switching , ( Guidance Notes )
● Guidance Note 3 , Inspection & Testing , ( Guidance Notes for BS-7671 )
● Guidance Note 4 , Protection from Fire , ( Guidance Notes for BS-7671 )
● Guidance Note 5 , Protection Against Electrical Shock , ( Guidance Notes for BS-7671 )
● Guidance Note 6 , Against Overcurrent , ( Guidance Notes for BS-7671 )
● Guidance Note 7 , Special Locations ( IEE Regulations )
● Guidance Note 8 , Earthing & Bonding ( Standards and Compliance )
● Guidance Note GS-38 , Electrical Equipment ,
“ GN-3 “

● ( Band I / 50V & Band II / 1000V - Definitions , p-31

The Frequency of Periodic , Inspecting & Testing and Test is Dependant on the Type of Installation ,
The Environment and the Type of Use ( BS-7671 Wiring Regulations ) “Construction Utilization and Environment this – App , 5 ( BS-7671

This comes under , Guidance Note 3
Periodic
It is Very Important that the Extent & Limitations of the Inspection and Test is Agreed with the Person Ordering
The Work before Commencing Work , ←←←

Before the Extent & Limitations can be Agreed , Discussion between ALL Parties Involved must take Place ,
The → ( Client ) ← will know why they want the Inspection Carried out & the Person who Carrying out the Inspection & Test should have
The Technical Knowledge and Experience to give the Correct Guidance ,

Remember this One , this mite Come up in the Future
This is one of many I was stung on .

 

[amberleaf]

Observations & Recommendations’
Defects , if any Must be Recorded Accurately and Codes Given ,
Codes to Indicate the Level of Attention Required ,

Code 1 ,
Requires Urgent Attention ,
Anything which could Compromise the Safety of those using the Installation should be Entered here
This would include Lack of Earthing , Undersized Cables , Damaged Accessories , High Zs Values ,
It is up to the Inspector Carrying out the Inspector to make a Judgement

Code 2 ,
Requires Improvement ,
Defects which do Not Immediately cause the Installation to be Regarded as Unsafe but could be Problematic in the Future ,
This could be , Corrosion , Old Cables such as Lighting Cables with No CPC , Labels missing ,
It is up to the Inspector Carrying out the Inspection to make a Judgement

Code 3 ,
This Could be anything that the Inspector who is Carrying out the Inspection & Test is Concerned about ,
But which is Outside of the Agreed Extent of the Inspection ,
Maybe a Circuit which Cannot be Traced , or Instruments Values within the Required Parameters – Anything that Might cause Concern ,

Code 4 ,
Does Not Comply with BS-7671
As the Requirements’ of BS-7671 are Amended , Parts of the Installation which would have Complied when the Installation was New ,
May now Not Comply ,
This could be , Sockets-Outlets that could be used to Supply Portable Equipment Outdoors ,
Not Protected by RCD ,CPCs which have been Sleeved with Green Sleeving & Not Green / Yellow ,
Switch returns Not Identified on Older Installations ,

Responsibility of the Tester carrying out the Inspection to Decide on which Code ,
It is up to the Inspector Carrying out the Inspection to make a Judgement

Assessment

This will Either be Satisfactory or Unsatisfactory ,
If the Observation Area of the Form has any Defects Other than Code 4 ,
The Assessment Must be Unsatisfactory ,

Any Change of Environment , that may have an Effect on Installation ,
Earthing Arrangements
Bonding
Isolation
Age
Safety
Ware-Tear

City & Guilds 2392 – 10 level 2 Certificate
Fundamental Inspection , Testing & Initial Verification

Testing of Electrical Installations :
Continuity – Methods 1 and 2 ( Continuity ( Ω ) Current (A)
Insulation resistance test ( Insulation ( MΩ ) Voltage (V)
Earth Loop impedance ( Ω ) Fuse (A)
Prospective fault current ( Ief / Ia )
Guidance Note 3 ( Schedule of test results )

● When Two RCDs are Connected in Series , to provide Discrimination , the first RCD should be an S –Type , RCD with built in time Delay should Not be Used to Provide Personal Protection , ● For an Installation forming part of a TT systems , a 100mA RCD is generally Installed at the Origin . a Time- Delayed or 100mA “S –Type ( or selective ) device is Often Used to Permit Discrimination with a Downstream 100mA Device , ● where an RCD is fitted only because the Earth Loop Impedance is to High for Shock Protection to be Provided by an Overcurrent Device , TT Systems ,

“ Testing Polarity “
● Polarity Test is Carried out with a Loop Tester ( Polarity Test can Confirm Correct Connection of Conductors within an Edison
Screw Lamp 612.5.2 (ii)

● The Easiest Method of Confirming Polarity on a Standard Ring Final Socket Outlet Circuit would be during ,
( The Continuity of Ring Final Conductors Test ) ↔ “ Test Prior to the Installation Being Energized “

● The Easiest Method of Confirming Polarity on a Standard Lighting Circuit would be During ,
( The Continuity CPC Test ) ↔ “ Test Prior to the Installation Being Energized “

● When Conducting a Continuity of CPC test , what other Test can be Carried Out at the same time , on the same Circuit ,
using the same Test Instrument and Settings , ( Polarity ) ↔ “ Test Prior to the Installation Being Energized “

● A Polarity Test is Conducted to Verify that ,
( Every Protective and Single Pole Device is Connected in the Line Conductor Only ) 612.6 ,

● A Polarity Test should be carried out on New Installation , ( Before Installation has be Energised )

● A Polarity Test is Preformed on Edison Screw lampholders to , Ensure the Centre Contact is Connected to the Line Conductor (ii) 612.6

● The Outer Contact of a Centre-Contact ( ES ) Lampholder , must be Connected to the , ( Neutral Conductor ) (ii) 612.6

● Polarity Tests on Final Circuits are Usually Carried out , ( During the Protective Conductor Continuity Test ( R1 + R2 )

“ Testing Periodic “

● Person Responsible for Specifying the First Periodic Inspection on an Installation , ( The Person Responsible for the Design )

● Periodic Inspection Report “ Forms “ ,
( This Report is Intended to be Issued Only for the Purpose on Condition of Existing Electrical Installation ) p-339 ,

● BS-7671 does Not give Specific Details on the Frequency of Periodic Inspection & Testing of Domestic Installation , 622.1 ,
Guidance Note-3 ( Suggests Every 10 years or Every Change of Occupancy )

● A Prospective Fault Current would be Recorded on A , ( Periodic Inspection Report )

● When Carrying out a Periodic Inspection on a Public House , which one of the following would Not Determine the Extent and
Limitation of the Report , ( The Original Designer )

● A Periodic Inspection Report would be Carried out on , ( An Existing Property )

● During a Routine Periodic Inspection , the Person who Determines the time to the Next Periodic Inspection would be the ,
( Inspection & Tester )

“ What is a Polarity Test “

● Basically it is a Test that Creates a Circuit using the Phase Conductor and the Single Pole Device ,
Breaking the Circuit when Operating the Device ,
Means that the Reading on the Instrument will Change ,
Confirming that the Device must be Connected in the Phase Conductor ,

● Minor Works Certificate ,

May be used only for an Addition or Alteration to a Single Circuit that does NOT Extend to the Provision of a new Circuit ,
Appendix 6 , p-331 , (ii ) ( vi )

● On a Minor Certificate it is “ Necessary to Record ” , ( Prospective Fault Current )

● A Minor Works Certificate should Contain ( Earth Fault Loop Impedance )

● On a Minor Works Certificate it is “ Not Necessary “ to Record ( Ze )

● After Wiring an Additional light fitting into a New Conservatory by Extending from an Existing Circuit , on Completion you should Issue ,
( Minor Works Certificate ) ↔ PS this is Addition & Alteration to an Installation , Regs , p-336

● After Adding an Extra Socket in Bedroom vie a Spur off an Existing Socket , the Customer should be Provided with
( Minor Works Certificate ) ↔ PS this is Addition & Alteration to an Installation , Regs , p-336

● In a Mechanics Workshop , the Repositioning of an Emergency Stop Button would Require the Completion of ,
( Minor Works Certificate ) ↔ PS this is Addition & Alteration to an Installation , Regs , p-336

● Isolation at the Source of a 3-Phase 4 -Wire Installation and Forming Part of a TN System may be Provided by a
( Three Pole Manually Operated Switch )

● Discrimination Occurs when ( Only the Plug top fuse Operates when a Portable Appliance Develops a Fault )

● Which of the Following is “ Not “ Part of the Earth Fault Loop Impedance Path Within a TN-S Systems
( Neutral Conductor within the Consumers Installation )

● According to BS-7671 what Minimum Level of Fault Current will be Required to Operate a BS-1361 5A Fuse 0.2sec ( 25A )
Regs , fig, 31 – K1 / R1 , Phase Conductor

● in the Equation S = √ I2 x t / k what does the Symbol “ I “ Signify ( Circuit Fault Current )

● in the Equation what does the Symbol “ S “ Signify ( Required Minimum size of the CPC )

● A Short-Circuit Current is Defined as an Overcurrent Occurring in a Circuit when a ( Fault of Negligible Occurs
Between Phase & Neutral Conductors

 

[amberleaf]

● The Prospective Fault Current would be Recorded on a , Electrical Installation Certificate ,

● an Essential Test that would be Carried Out for a Minor Works Certificate would be , Socket Outlet Polarity ,

● Before Commencing the Inspection & Testing of a New Installation , Information you should have Available would be ,
External Loop Impedance ,

● Before Commencing the Inspection & Testing of a New Installation , Information you should have Available would be ,
Earthing Arrangement

● the Frequency of Periodic Inspections should be Determined by , the Type and use of Installation , the Frequency of
Maintenance and , the External Influences to which the Installation is Subjected ,

● After Installation of a New Shower in a Small Terraced House where there was Not one Previously ,
The Customer Should be Provided on Completion with , Electrical Installation Certificate ,

● When Performing an Earth Fault Loop Impedance Test , the Quick Method of Determining Compliance with BS-7671
Would be by Comparing the Results to , , Guidance Note 3 ,

● This is to Check on the Insulation Quality between Live Conductors’ and Live Conductors’ and Earth ,
● Mains must be Isolated for this test ,
● Instruments must generate a DC test voltage ↔ 500 volts
● Minimum acceptable Insulation resistance 61. p/158
● Caution must be Exercised when Conducting this Test ,

An Insulation Résistance Test is done to Establish the Insulations
An Insulation Résistance Test Establishes the ( Confirmed of the Cables )

The Electrical Separation of ELV and LV Circuits is Confirmed with an
● Insulation Résistance test ( ELV – LV – 500V dc )

In a Non-conducting location where the voltage does “ NOT “ Exceed 500 volts the Résistance of the Walls or Floors must Not be Less than
( The Résistance of the walls or floors must Not be Less than 418.1.5. (i) 50kΩ

In a Non-conducting location where the voltage “ Does “ Exceed 500 volts the Résistance of the Walls or Floors must Not be Less than
( The Résistance of the walls or floors must Not be Less than 418.1.5. (ii) 100kΩ

In a Non-conducting location , Insulation between any Extraneous Conductive parts
and Exposed Conductive parts is Tested at what Voltage
( Minimum Insulation Test voltage is 2000V , (iii ) 418.1.4

( 50V to 500V / 1.0MΩ ←
( SELV = 50v a.c / 250d.c ←

● Where the Circuit Includes Electronic Devices which are Likely to Influence the Result or be Damage ,
Only a Measurement between the Live Conductors Connected together and the Earthing Arrangements shall be Made ,
612.3.3

● Insulation Résistance shall be Measured between Live Conductors and between Live Conductors
And the Protective Conductor Connected to the Earthing Arrangement , Where Appropriate During this Measurement
Line & Neutral Conductors may be Connected Together ,
612.3.1 ( No Breakdown of the Conductor Insulation )

 

[fog]

Hi Amberleaf and many many thanks for brilliant information and the answer to many of my questions.

 

[amberleaf]

“ Electrical Certificate’s Issued ,

● The Prospective Fault Current would be Recorded on a , ( Electrical Installation Certificate ) ( PFC )

● A Prospective Fault Current would be Recorded on A , ( Periodic Inspection Report ) ( PFC )

● On a Minor Certificate it is “ Necessary to Record ” , ( Prospective Fault Current ) ( PFC )

“ Insulation Resistance Testing “
● Prior to performing an Insulation Resistance test , you should , ( Disconnect all Voltage Sensitive Devices )
● Prior to performing an Insulation Resistance test , you should , ( Ensure all Lamps are Removed )

● An Insulation Resistance Test on a Three Phase Installation can be more Easily Performed by ,
( Testing between Earth and all Live Conductors Connected together )

● According to BS-7671 17th Edition , the Minimum Insulation Resistance Value should be Investigated below , ( 2MΩ )

● Where the Circuit includes Electronic Devices which are likely to influence the Results or be Damaged ,
Only Measurement between the Live Conductors Connected together and the Earthing Arrangements shall be Made , 612.3.2

● It is a Good idea when Performing an Insulation Résistance Test on a Large Installation , To subdivide Circuits’ to avoid ,
( False Reading from Parallel Résistance )

● When an Insulation Résistance Test on a large Installation returns Unexpectedly Low readings , your course of action would be ,
To Individually Test each Circuit )

● Which Test is used to Prove that the Circuit under Tests has No Dangerous Short-Circuits Prior to the Circuit being Made “ Live ,
( Insulation Résistance ) ↔ This Test Verifies ( Proves ) that the Insulation of the Cables in good Order ,

● Which Test is Used to Prove that the Circuit Under Test has no Dangerous Short-Circuits Prior to the Circuit being Made Live
( Insulation Résistance ) “ Proves “ that the Insulation of the Cables in Good Working Order

● A Circuit Breaker for a Socket-Circuit is Tripping Intermittently , this Occurs even if there is Nothing Plugged in , the Likely Cause is ,
( Insulation Failure )

● Insulation Resistance Testers are Designed to Measure , ( High Résistance Using a dc voltage ) ←

● Damp Getting into a Cable can Lead to which Type of Fault , ( Insulation Failure ) ←
( This can Lead to ” Nuisance Tripping ” of the Protective Device )

● A Circuit Breaker for a Socket Circuit is Tripping Intermittently , This Occurs Evan if there is Nothing Plugged in ,
( The Likely Cause is , ( Insulation Failure )
( This would Match the Symptoms , it can be Caused by Overheating , Damp , or Mechanical Damage ,

● When Carrying out an Insulation Resistance Test between Conductors on a One-Way Lighting Circuit , have the
( Switch Closed and Lamp Out )

If an Additional Alternative has been Carried Out it Must Not ,
( Increase the Electrical Consumption )

610.2 The Result of the Assessment of the Fundamental Principles , Sec 131 ,
The Results of the Assessment of an Electrical Installation with Regards to Protection for Safety shall be Made Available to the ,
Together with the Information Required by Regulation 515.9.1 ( Inspector Prior to Carrying Out the Inspection and Test )

Information such as Diagrams and Schedules shall be made Available to the ,
( The Inspector Prior to Carrying out an Inspection and Test )

612.9 Earth Fault Loop Impedance

Where Protective Measures are Used which Require a Knowledge of “ Earth Fault Loop Impedance “ the Relevant Impedance Shall be Measured , or Determined by an Alternative Method ,
● Calculation ,
● Measurement

Before Inspecting the Condition of Electrical Equipment Installed in a New Unoccupied Building the Inspector Should
( Check for Components that may be Susceptible to Damage During Testing )

Any Addition to an Existing Installation Should ( Not Impair the Safety of the Existing Installation )
↔ ( Remember to Disconnect any Florescent Luminaries when Testing ) ↔

Which of the Following Duties is “ Not ” the Responsibility of the Inspector ( To Carry out Maintenance and Repairs on the Installation )

Records of Inspections and Test Results Should be Kept During the Life of an Installation , this will Enable ( Deterioration to be Identified )

According to BS-7671 No Additions or Alterations Should be Made to an Existing Installation Unless
( The Existing Installation Conforms to Current Regulations )

When Inspecting for Adequate Protection Against Direct Contact which of the following Does Not Require Inspection ,
Presence and Condition of , ( Connection of CPCs )

A Visual Inspection of a “ New “ Installation must be Carried Out ( During Erection and before Testing )

Which One of the Following Procedures would be Correct if Permission to Disconnect
Information Technology Equipment has “ Not “ been Received ( Do Not Apply Tests )

A Continuity Test at Each Socket-Outlet of a Ring Final Circuit is Carried Out to make sure that ( No Multiple Loop Exist )

When Carrying Out a Prospective Short Circuit Fault Current Test on a Three Phase System
The Approximate Fault Current between Phases Should be ,
( Double the Fault Current between One Phase and Neutral )

When Carrying Out a Prospective Short Circuit Current Fault Test on a Three Phase System the Approximate
Fault Current between Phases Should be ( PSCC ) Continuity of the Ring Final Circuit )

When Electrical Accessories have Neon Indictor Lamps Inaccurate Reading can Occur when Tests are
Carried Out to Determine the Resistance ( Insulation between Phase and Neutral )

A Legible Diagram , Chart or Table Relating to A Installation “ Must “ be Provided to Indicate
( Any Equipment Vulnerable to a Test )

What is the Maximum Earth Fault Loop Impedance Allowed when Using a 20A Type C Circuit Breaker
Giving a Disconnection Time of 5sec The Normal Voltage to Earth ( Uo ) is 55v = 0.28Ω Regulation’s , table 41.6 /

What is the Maximum Earth Fault Loop Impedance Allowed when Using a 20A Type BS-2-2 ( gG ) ↔ ( Motor Circuits Only )
Giving a Disconnection Time of 5sec The Normal Voltage to Earth ( Uo ) is 55v = 0.28Ω Regulation’s , table 41.6 /

The Commissioning Process take Place ( After an Installation has be Inspected & Tested )

Certification & Reporting
“ Before an Installation or Additions & Alterations to an Installation is Energised
Inspection & Testing Must be Carried Out to Ensure the
( Requirements of BS-7671 have Been Meet and an Appropriate Certificate Must then be Issued )

 

[amberleaf]

This from the Red Book , 17th
1, Initial Inspection & Testing

Form ( 1 ) to ( 4 ) are Designed for Use when Inspecting & Testing a “ New Installation “
Or an Alteration or Addition to an Existing New Installation ( Form Comprise the Following )

1, Short form of Electrical Installation Certificate ( to be Used when One Person is Responsible for the Design )
Construction , Inspection & Testing of an Installation ,

2 , Electrical Installation Certificate ( Standards form from Appendix 6 / BS-7671

3 , Schedule of Inspections ,

4 , Schedule of Test Results ,

( “ Note on Completion and Guidance for Recipients are Provided with the Form )

2 , Minor Works ,

The Complete set of Forms for Initial Inspection & Testing may be Appropriate for Minor Works
When an Addition to an Electrical Installation does “ Not ” Extend to the Installation of a New Circuit
The Minor Works form may be Used , this form is Intended for such Work as the Addition of a New Socket-Outlet
Or Lighting Point to an Existing Circuit , or for Repair or Modification ,

Form ( 5 ) is the Minor Electrical Installation Works Certificate from Appendix 6 / BS-7671
( Notes on Completion and Guidance for Recipients are Provided with the Form )

3 , Periodic Inspection
Form ( 6 ) the Periodic Inspection Report from Appendix 6 of BS-7671 ,
Is Used when Carrying Out Routine Periodic Inspection & Testing of an Existing Installation ,
It is Not for Use when Alterations or Additions “ are Made A Schedule of Inspections ( 3 ) and Schedule of Test Results (4 ) should Accompany the Periodic Inspection Report ( 6 )

( “ Note on Completion and Guidance for Recipients are Provided with the Form )

During the Initial Verification of an Installation , which of the following forms Part of the Checklist ,
( Presence of Diagrams & Instructions’ ,

The Paperwork that Should be Issued on Completion of “ New “ Certificate ,
( Schedule of Test Results , Schedule of Inspection and an Electrical Installation Certificate ,

A Minor Work Certificate Should be Issued ,
( Where an Alteration “ Not” Requiring an Additional Circuit is Needed )

Periodic Inspection Report would be Carried Out on ,
( Existing Property )

The Person Responsible for Specifying the First Periodic Inspection on an Installations is ,
( The Person Responsible for the Design )

Segregation of Safety Circuits

Regulations 528.1 & 560.1
Fire Alarm , Emergency Lighting to be Segregated from each Other
And Other Circuits unless Wired in Cables with an Earthed Metal Sheath with an Insulated Covering ,
This could be Mineral Insulated Firetuff & FP200

Identification

Presence of Diagrams , Instructions , Circuit Charts & Similar Information
Regulations 514.9 & 560.7.9
Circuit charts , Plans , Past Inspection and Test Certificates and Schedules must be Available
For Domestic Installations , Circuit Identification would be a Minimum Requirement on an Older Installation ,

Presence of Danger Notices and Other Warning Notices
Regulations 514. Earth Bonding Labels ,
Voltage Warning , Isolation ,
Harmonization of Colours & RCD Testing are Common ,

Labelling of Protective Devices , Switches & Terminals
Regulations 514.1 & 514..8
Protective Devices Labelled ,
Conductors in Sequence ,
Switches & Isolators Marked to Identify the item they Control
If this is Not Obvious ,

Identification of Conductors
Regulations 514.3.1
Coloured Sleeve on Switch Wires or where Line Conductors’ are Not Clearly Identified ,

“ Statutory Regulations “ App-2 - 241

Regulation 28 of The Electricity Safety , Quality and Continuity Regulations 2002 ,
Requires Distributors’ to Provide the following Information to Relevant Persons Free of Charge ,

● The Maximum Prospective Short-Circuit Current at the Supply Terminals ,
● The Maximum Earth Loop Impedance of the Earth Fault Path Outside The Installation ( Ze )
● The Type and Rating of the Distributors’ Protective Device or Devices Nearest to the Supply Terminals ,
● The Type of Earthing System Applicable to the Connection ,
● The Number of Phases of the Supply ,
● The Frequency of the Supply and the Extent of the Permitted Variations ,
The Voltage of the Supply and the Extent of the Permitted Variations ,

543.4.1 Pen Conductors shall Not be Used within an Installation Except as Permitted by Regulation 543.4.2
In Great Britain , 8 (4 ) of the Electricity Safety , Quality and Continuity Regulations 2002 ,
Prohibits the Use of PEN Conductors in Consumer’s Installation ,
543.4.2
The Provisions of Regulations 543.4.3 / 543.4.9 may be Applied Only ,
(ii) Where the Installation is Supplied by a Privately Owned Transformer or Convertor ,
(iii) Where the Supply is Obtained from a Private Generating Plant ,

( Great Britain the Use of Combined Protective and Neutral ( PEN ) Conductors is Prohibited in Consumers Installations
One Exception , Supply Obtained from Private Generating Plant ,

IEE Guidance Note 3 Inspection & Testing
This Guidance Note is Part of a Series Issued by the IEE to give Specific Guidance The Inspection & Testing Procedure in a Simplified and Detailed Manner ,

Domestic Electricians
Electrical Installation Certificate Regulation BS-7671 p-334 Start There ,

The Electrical Installation Certificate is Used for the Initial Certification of a New Installation or for an Addition or Alteration
To an Existing Installation where New Circuits have be Introduced ,

The Certificate should be Accompanied by the Schedule(s) of Inspections and Schedule(s) of Test Results ,

The Electrical Installation Certificate should be Completed and Signed or Otherwise Authenticated by a Competent Person
( or Persons ) in Respect of the Design , Erection , Inspection & Testing of Work ,
If the Design , Construction and Testing is Carried Out by One Person a Single Signature Declaration may Replace the Three Signatures’ Required on the Certificate ,

Once Completed the Original Certificate and Schedules should be Given to the Person Ordering the Work
As Required by Regulation 632.3 BS-7671 : 2008 The Contractor should keep a Copy of the Certificate and Schedules ,

The Recommended time Interval before the First Periodic Inspection is Carried Out can
Be Obtained from the IEE Guidance Note 3

Once the Initial Periodic Inspection has been Carried Out the Next Periodic Inspection should take into Consideration
The Frequency and Quality of Maintenance the Installation is Expected to Receive During its Intended Life ,
The Period should then be Agreed between the Designer , Installer and any Other Relevant Body ,

Minor Electrical Installation Works Certificate

Minor Electrical Installation Works Certificate is Used as an Alternative to the Electrical Installation Certificate where the
Minor Electrical Installation Work is an Addition or Alteration that does Not Include the Provision of a New Circuit or Circuits

The Certificate may also be Used for the Replacement of Equipment such as Accessories & Luminaries ,
This does Not Extend to such things as Consumer Unit or Distribution Boards etc

Inspection , Testing and Certification should always be Carried Out Regardless of the Extent of the Work Undertaken ,

 

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The Electricity at Work Regulations apply to the Process of Inspection & Testing
The following Regulations are relevant to the Inspection and Testing Process for the Safety of Persons Carrying Out the Inspection & Testing

Regulation 3
Persons on Whom Duties are Imposed by these Regulations :
The Electricity at Work Regulations 1989 Apply to ;
(i) Employer e.g. Electrical Contractor ,
(ii) Employee e.g. Inspector ,
(iii) Self-Employed e.g. Electrician / Inspector ,

Regulation 4
Systems , Work Activities & Protective Equipment :
(i) Every Work Activity shall not Give rise to Danger e.g. Test Voltages
(ii) Any Personal Protective Equipment shall be Suitable , Maintained and Used Properly e.g. Hard Hat , ←

Regulation 5
Strength and Capability of Electrical Equipment ,
(i) No Electrical Equipment Shall be put into Use where its Strength and Capability may be Exceeded in such
A Way as May Give Rise to Danger e.g. Poorly Insulated Hand Tools & Test Equipment Not to GS-38 ( H.S.W.A ) ←

Regulation 6
Adverse or Hazardous Environment
(i) Electrical Equipment Exposed to Mechanical Damage , Weather , Natural Hazards’ , Temperature , Pressure ,
Water , Dirt , Dust , Corrosion , Flammable or Explosive Substances Shall be Suitable e.g. Test Instruments , ←

Regulation 7
Insulation , Protection and Placing of Conductors :
(i) All Conductors in a System which may Give Rise to Danger shall Either be Suitably Covered with Insulating Material
Or Suitably Placed e.g. Test Probes No More than 2mm ( Maximum 4mm ) ↔ Guidance Note GS-38 , Electrical Equipment ,

Regulation 8
Earthing or Other Suitable Precautions
(i) Precautions Shall be Taken Either by Earthing or Some Other Means to Prevent Danger Arising e.g.
Do Not Carry Out Live Tests such as External Loop Impedance ( Ze ) or Final Circuit Loop Impedance ( Zs )
With Earth Conductors Disconnected , ( Guidance Note 7 , Special Locations ( IEE Regulations )

Regulation 9
Integrity of Referenced Conductors
(i) if a Circuit Conductor is Connected to Earth or to Any Other Reference Point it Should Not Give Rise to Danger
If Disconnected e.g. Neutral Points which are Earthed as in TN-C / TN-C-S Systems should Not be Disconnected from their
Earth Terminal when Carrying Out Live testing as in Regulation ( 8 ) ←←

Regulation 10
Connections
(i) Where Necessary to Prevent Danger , Every Joint and Connection shall be Mechanically & Electrically Sound e.g.
Ensure all Connections are Tight when Carrying Out Functional Testing ,

Regulation 11
Means for Protecting from Excess of Current
(i) Effective Means , Suitable Located , shall be Provided for Preventing from Excess of Current Every Part of a System
As may be Necessary to Prevent Danger e.g. ↔ Do Not Replace or Link ( Short ) ↔ Out Fuses or Circuit Breakers During
Testing , Ensure Test Equipment has Suitable Protection such as Fused Test Leads ,

Regulation 12
Means for Cutting off the Supply and for Isolation
(i) Where Necessary to Prevent Danger , Suitable Means shall be Available for Cutting of the Supply e.g.
Tests such as Continuity of Protective Conductors and Insulation Résistance are Carried Out on Dead Installation or Circuits ,
It is Therefore Necessary to Carry Out a Safe Isolation Procedure Prior to Testing ,

Class 1 Equipment ( Exposed Metal Work Earthed )
Class 11 ( Separated Extra Low Voltage )
Class 111 Equipment ( SELV Supply )

( Assessment of General Characteristic would Include )
Maintainability , Safety Services and Continuity of Service
The Electricity at Work Regulations 1989
Require Every System to be Maintained such as to Prevent Danger
Consequently , all Installation Require Maintaining ,

Regulation 13
Precautions for Work on Equipment Made Dead
(i) Adequate Precautions shall be Taken to Prevent Electrical Equipment ,
Which has been Made Dead , in Order to Prevent Danger while Work is Carried Out on or Near that Equipment , from
Becoming Live e.g. Carry Out a Safe Isolation Procedure ,

Regulation 14
Work on or Near Live Conductors
(i) No Person shall be Engaged in any Work Activity on or Near any Live Conductors’ Unless it is Unreasonable for them to be Dead ,
It is Reasonable in All Circumstances or Suitable Precautions are Taken to Prevent Injury e.g.
Carry Out Safe Isolation Procedure ,

Regulation 15
Working Space , Access and Lighting
(i) For the Purpose of Enable Injury to be Prevented , Adequate Working Space ,Adequate Means of Access , and Adequate Lighting Shall be Provided at All Electrical Equipment in Circumstances which May Give Rise to Danger ,
e.g. Temporary Lighting

Regulation 16
Persons to be Competent To Prevent Danger & Injury
(i) No Person shall be Engaged in any Work Activity where Technical Knowledge or Experience is Necessary to Prevent Danger or ,
Where Appropriate , Injury , Unless he / Possesses such Knowledge or Experience ,
Or is Under Such Degree of Supervision as May be Appropriate having Regard to the Nature of the Work e.g.

Regulation 8 “ right one “
Earthing or Other Suitable Precautions
(i) Precautions Shall be Taken Either by Earthing or Some Other Means to Prevent Danger Arising e.g.
Do Not Carry Out Live Tests such as External Loop Impedance ( Ze ) or Final Circuit Loop Impedance ( Zs )
With Earth Conductors Disconnected , Guidance Note 8 , Earthing & Bonding ( Standards and Compliance )

State the Need for Instruments’ to be Regularly Checked and
The Need for Compliance with the Requirements of BS-7671:2008
HSE Guidance Note GS-38

All Instruments’ must be Regularly Checked to Ensure that they are ,
(1) Not Physically Damaged ,
(2) In Full Working Order ,
(3) Calibrated Correctly and to Date ,
(4) Compliant with GS-38 with Regards to Test Leads , the Main Requirements being ,

(i) Exposed Probe Ideally no more than 2mm / 4mm Maximum
(ii) Finger Guards to Stop Fingers Slipping onto Live Contact(s) ,
(iii) Test Leads or Test Probes include Current Limiting e.g. Fuse in Test Leads ,

(5) Safe to Use ,

Additional Protection RCD Test ↔ Instrument on mA Range 230v Supply ,
( Live Test , ½ No Trip ( x1 ( 300mS ) & x5 ( 40mS )

● Verification of Voltdrop ( Evaluate Using the Loop Impedance Value ) ↔ Note Normally Required on Initial Verification ,

● Electrical Separation ( Instrument on High Ohms ( MΩ ) Megohms Range ↔ Instrument Provides a Low Voltage ( 500v dc at 1mA )

● Insulation Résistance ( Instrument on High Ohms ( MΩ ) Megohms Range ↔ Instrument Provides a Low Voltage
( 250 / 500 / 1000 d.c ) at 1mA ( Regs table 61 )

● Insulation / Impedance of Floors & Walls ( Instrument on High Ohms ( MΩ ) Megohms Range ↔ Instrument Provides a Low Voltage
( 500v d.c. at 1mA to Read kΩ )

● Earth Fault Loop Impedance ↔ R1 + R2 ↔ ( Instrument on Low Ohms (Ω) Continuity Range ( Live Test ≈ ≈ ≈
( if New Installation Use OSG t-2D ↔ Cold Test at 80% , 1st ←←← ( 2392-10
( Regs Table 41.3 is Used for Warm Test 100%

● Prospective Fault Current ( Instrument on kA Range 230v Supply ( Live Test ≈ ≈ ≈ Dedicated Instrument ( or Settings )

● Check of Phase Sequence ( Instrument on Phase Sequence Setting 400v ( Live Test ≈ ≈ ≈ Dedicated Instrument ( or Settings )

● Functional Testing ( Check Test Button on RCD , Switches , Controls , Locks etc ,

● Electrical Test Equipment for Use by Electricians

Guidance Note GS-38
Circuits with Rated Voltages Not Exceeding 650v

LAW , ←←←

(2) The Electricity at Work Regulations 1989 Require those in Control of Part or all of an Electrical System to Ensure
That it is Safe to Use and that it is Maintained in a Safe Condition , This Section does not seek to give a Definitive Interpretation of the Law ,
It Summarises the Main issues to be borne in Mind when Carrying Out Electrical Testing ,
(3)
The Most Important Features that are Relevant for Electrical Test Equipment for Use by Electrically Competent People are as Follows ,

(a) Equipment should be , so far as Reasonably Practicable ,
(i) Constructed ,
(ii) Maintained , And
(iii) Used in a Way to Prevent Danger ,
(b) No Live Working Unless ,
(i) it is Unreasonable to Work Live , AND
(ii) it is Reasonable to Work Live , AND
(iii) Suitable Precautions are Taken to Prevent Injury ,

(c) Work must be Carried Out in a Safe Manner , Factors
To Consider when Developing Safe Working Practices
Include ,
(i) Control of Risk while Working ,
(ii) Control of Test Areas ,
(iii) Use of Suitable Tools & Clothing , Steel caps Boots ,
(iv) Use of Suitable Insulated Barriers ,
(v) Adequate Information ,
(vi) Adequate Accompaniment ,
(vii) Adequate Space , Access , Lighting ,

(d) People At Work Must ,
(i) Prevent Danger and Injury ,
(ii) Have Adequate Training , Skill & Experience ,
(iii) Have Adequate Supervision when Appropriate ,

 

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● Continuity of Protective Conductors’ ( Instrument on Low Ohms (Ω) Continuity Range , Instrument can read Values Less than , 1Ω
● Continuity of Protective Conductors’ ( R1+R2 Values , Metalwork & Effective ( IR ) Testing

● Continuity of Ring Final Circuit Conductors’ ( Instrument on Low Ohms (Ω) Continuity Range , Instrument can read Values Less than , 1Ω
● Continuity of Ring Final Circuit , ( R1+R2 Values , No Interconnected Ring )


● Insulation Résistance ( Instrument on High Ohms ( MΩ ) Megohms Range ↔ Instrument Provides a Low Voltage
( 250 / 500 / 1000 d.c ) at 1mA ( Regs table 61 )

● Insulation Résistance ( N0 Short between Line , Neutral & Earth


● SELV ( Instrument on High Ohms (MΩ) Megohms Range ↔ Instrument Provides a Low Voltage ( 250v dc at 1mA )

● SELV ( No Connection between Low & Extra Low Circuits )


● PELV ( Instrument on High Ohms (MΩ) Megohms Range ↔ Instrument Provides a Low Voltage ( 250v dc at 1mA )
● PELV ( No Connection between Low & Extra Low Circuits )


● Electrical Separation ( Instrument on High Ohms ( MΩ ) Megohms Range ↔ Instrument Provides a Low Voltage ( 500v dc at 1mA )

● Electrical Separation ( No Connection between Low & Extra Low Circuits )


● Insulation / Impedance of Floors & Walls ( Instrument on High Ohms ( MΩ ) Megohms Range ↔ Instrument Provides a Low Voltage
( 500v d.c. at 1mA to Read kΩ )

● Insulation / Impedance of Floors & Walls ( Effectiveness of High Résistance / Impedance Location )


● Polarity ( Instrument on Low Ohms (Ω) Continuity Range , Instrument can read Values Less than , 1Ω

● Polarity ( Switches , Fuses , Breakers etc in Side of Circuit )


● Earth Electrode Résistance ( Instrument on Low Ohms (Ω)Continuity Range , Dedicated Instrument ( or Setting ) read Less than , 1Ω
Earth Rods , / Battery only ,

● Earth Electrode Résistance ( Resistive Contact of Electrode to Ground )


● Earth Fault Loop Impedance ↔ R1 + R2 ↔ ( Instrument on Low Ohms (Ω) Continuity Range ( Live Test ≈ ≈ ≈ ≈
( if New Installation Use OSG t-2D ↔ Cold Test at 80% , 1st ←←← ( 2392-10
( Regs Table 41.3 is Used for Warm Test 100%

● Earth Fault Loop Impedance ( To Meet Final Circuit Disconnection time in Event of Fault )


● Prospective Fault Current ( Instrument on kA Range 230v Supply ( Live Test ≈ ≈ ≈ ≈ Dedicated Instrument ( or Setting )

● Prospective Fault Current ( To Ensure Protective Devices can Disconnect Fault Effectively ) ↔ ( PFC )


● Check of Phase Sequence ( Instrument on Phase Sequence Setting 400v ( Live Test ≈ ≈ ≈ ≈ Dedicated Instrument ( or Settings )

● Check of Phase Sequence ( To Ensure 3 Phase Motors etc Rotate Incorrect Direction )


● Functional Testing ( Check Test Button on RCD , Switches , Controls , Locks etc ,

● Functional Testing ( To Test RCD Test Button , Switches’ , Breakers , Locks etc Operate )


● Verification of Voltdrop ( Evaluate Using the Loop Impedance Value ) ↔ Note Normally Required on Initial Verification ,

● Verification of Voltdrop ( To Ensure Voltage at Load End is within Required Limits )

Domestic Electrician 2392-10

Insulation Résistance , 2392-10

Cables Connected in Parallel ,

The Formula for Calculating Overall Insulation Résistance of Circuits in Parallel ,

1 = 1 + 1 + 1 + MΩ
----- ----- ----- -----
RT R1 R2 R3

Where RT is the Overall Insulation Résistance ,
Three Circuits’ of Résistance 1MΩ 2MΩ 4MΩ Connected in Parallel ,
R1 ,R2 , R3

1 = 1 + 1 + 1
---- ---- ---- ----
RT R1 R2 R3

1 = 1 + 1 + 1
---- ---- ---- ---- ( 1 ÷ 1 + 1 ÷ 2 + 1 ÷ 4 = 1.75
RT 1 2 4

1 = 1 + 0.5 + 0.25 = 1.75
---- ---- ---- ----
RT

1 = 1.75
----
RT

RT = 1
----- ( 1 ÷ 1.75 = 0.57 MΩ
1.75

RT = 0.57 MΩ

Insulation Résistance
Precautions to be Taken before Testing Insulation Résistance ,

(a) Isolation of Circuits and Equipment , ♫
(b) Voltage Sensitive Equipment , ♫
(c) Electronic Components , ♫

(a) Isolation of Circuits and Equipment ,
The Following Procedure for Safe Isolation should be Taken , ♫
1 , Select a GS-38 Approved Test Lamp or Voltage Indicator , ♫
2 , Check Test Lamp / Voltage Indicator is Functioning Correctly by Testing on a Known Supply or Proving Unit ♫
3 , Determine whether Isolation is for Whole Installation or Specific Circuit(s)
4 , Locate Means of Isolation Ensuring there is No Standby Supply Arrangement ,
5 , Switch Off and Lock Off Isolator , Circuit(s) e.g. Fuse , Switches’ , Isolator , MCB etc ♫
6 ,Verify , Using Test Lamp / Voltage Indicator , Circuit(s) are Dead between Line(s) Neutral & Earth , ♫
7 , Erect Warning Notice(s) in Appropriate Position(s) e.g. at the Consumer Unit , ♫
8 , Re-Check Test Lamps / Voltage Indicator is Still Functioning Correctly , ♫
9 , Retain Key(s) for Locking Off Devices , ♫

(b) Before Carrying Out Insulation Résistance Testing it Must be Established that there is No Voltage
Sensitive Equipment Connected that may be Damaged or Malfunction because of Test Voltage Applied ,
May be Computers , Programmable Logic Controllers (PLCs) Programmers etc.
The Equipment would Either have to be Disconnected During Test ,
Or Insulation Test with Line(s) and Neutral Connected Together and Test between these and the Protective Conductor ,

(c) Before Carrying Out Insulation Résistance Testing it Must also be Established that there is No Electronic Components
That May be Damaged or Malfunction because of the Test Voltage Applied , Lamp Dimmer , this would have to be Removed
During Test and the Switch Wires Connected Together ,

Methods of Testing Insulation Résistance

Before Carrying Out Insulation Résistance Testing Ensure that ,

1 , All Lamps , Capacitors and Loads are Disconnected ,
2 , Voltage Sensitive Electronic Equipments such as Dimmer Switches , Touch Switches ,
Delay Timers , Power Controllers , Fluorescent Lamps Starters , Emergency Lighting ,
RCDs etc are Disconnected ,
3 , There is No Electrical Connections between Line(s) Neutral & Earth ,

● Verification of Voltdrop ( Evaluate Using the Loop Impedance Value ) ↔ NOT Normally Required on Initial Verification , ( Sorry this is the right one ) ←←←←←←

● As a Cable Increases in Length , Unlike the Conductor Résistance which Increases with Length ,
Insulation Résistance Decreases with Length ,

Formula for Calculating New Value of Insulation Résistance ,
( Insulation Résistance = Original Length x Initial Insulation Résistance )
“ New Length “

A Cable of Length 50 metres has an Insulation Résistance Value of 200MΩ if its Length
Is Increased to 100 metres , Calculate its Insulation Résistance ,

= 50 x 200
-------------- ( 50 x 200 = 10000.
100

= 10,000
-----------
100

= 100MΩ

● Earth Electrode Résistance ( Ze )

● Earth Fault Lop Impedance ( Ze ) ( Zs )

● Prospective Fault Current ( PFC )

 

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“ Cables “ & Stuff (1) this will make it easy for you all in one ?

● A Reference Method Indicates , ( The Instillation Method )

● A Final Circuit is Wired between the , ( Distribution Board and Current Using Equipment )

● The Reading Provided when Cross Connecting the Incoming Phase and the Outgoing CPC and Vice versa on a Final Ring Circuit Test would be
( R1 + R2 )

● What’s the Function of a “ Shorting Lead “ when Conducting Continuity , ( R1 + R2 ) Tests ( “ It Completes the Live to CPC Test Loop ” )

● An Initial Check at the End of a Ring Final Circuit would Not Indicate ( Interconnections )

● The Earth Fault Loop Impedance Reading on a Ring Final Circuit is best Achieved Using an Earth Fault Loop Impedance
Tester and , ( BS -1363 Fly Lead )

● When Applying the Rule of Thumb Method , the Value of Prospective Short-Circuit Current for a 3 Phase Supply should be ,
( Twice the Single Phase Value )

● When Carrying Out a Prospective Short Circuit Fault Current Test on 3 Phase Systems the Approximate Fault Current between Phases should be
( Double the Fault Current between One Phase & Neutral )

● the Most Convenient Method of Determining the Value of the Prospective Short Circuit Current at the Origin of an Existing Installation would be ,
( Measurement )

● Method of Determining the External Loop Impedance ( Taking Reading at the Origin of the Supply )

● Earth Fault Loop Impedance Test Performed on a Ring Circuit will Record
( Resistance of Line and Protective Conductors and External Loop Impedance

● Electrical Installations Shall be Divided into Circuits to ( Reduce Unwanted Tripping of RCD )

● To Ensure the Protective Device Operates Requires a ( Low Fault Loop Impedance Path with a Resultant High Earth Fault Current Flow )

● The Effects of Creating a Ring Final Circuit would be that the Overall Resistance of the Conductors would ( Decrease )

● The Resistance in Ohms , of a Conductor ( Increases with Increase of Cable Length )

● if you Double the Length of Wire ( you will Double the Resistance of the Wire )

● if you Double the Cross-Sectional Area of a Wire you will Cut its Resistance in ( Half )

● What is the Preferred Way of Reducing Excessive Voltage Drop in a Circuit , ( Increased Cable CSA )

● the Value will Decrease as we Move Farther away from the Intake Position ( Resistance Increases with Length )

● End to End Resistance Checks would be Carried out on a ! ( Ring Final Circuit )

● To Ensure the Protective Device Operates Requires A ( Low Fault Loop Impedance Path With a Resultant High Earth Fault Current Flow )

● As a Cable Increases in Length , Unlike the Conductor Résistance which Increases with Length ,
( Insulation Résistance Decreases with Length )

Residual Current Operated Circuit Breaker ( BS-EN 61008-1
BS-EN 61008-1 : 2004 Residual Current Operated Circuit –Breaker without Integral Overcurrent Protection for Household
And Similar Use ( RCCBs )
Replaces ( BS-EN 61008-1 - 1995 )
International Relationships ( EN-61008-1: 2004 Identical , IEC-61008-1: 1996
Amended by / AMD 17447 November 2007

BS-EN 61009-1 / 1995
Electrical Accessories , Residual Current Operated Circuit Breaker with Integral Overcurent Protection for Household and
Similar Uses ( RCBOs ) General Rule CU , Regs 41.3
International Equivalent EN-61009-1 / IEC 61009-1: 1991
Replaces by BS-EN 6009-1 : 2004 ( Remains Current ) Appendix 1 p-236

2.1 (a) BS-7671 IEE Regulations Define Extra-Low-Voltage a.c ( Not Exceeding 50V , ps this one is still ongoing

531.2.9 Where , for Compliance with the Requirements of the Regulations for Fault Protection or Otherwise to Prevent Danger , Two or More RCDs are in Series , and where Discrimination in their Operation is Necessary to prevent Danger , The Characteristics of the Devices shall be such that the Intended Discrimination is Achieved ,

411.8.3 Requirements for Fault Protection where a Circuit-Breaker is Used , the Maximum Value of Earth Fault Loop Impedance (Zs) shall be Determined by the Formula in Regulation 411.4.5 , Alternatively , the Values Specified in Table 41.6 may be Used Instead of Calculation for the Nominal Voltages (Uo) and the Type and Ratings of Overcurrent Device Listed therein ,

Operation of the Overcurrent Device in Tables of , 41.3 / 41.4 ( where Circuit Lengths’ need to be Limited )

132.11 Prevention of Electrical Equipment , the Electrical Installation shall be Arranged in such a way that No Mutual Detrimental Influence will Occur between Electrical Installation and Non- Electrical Installation Electrical Installation ( Condensation , Smoke , Heat , Thermal Installation , Electromagnetic Interference , / sec , 515 – 528 ,

Telecommunications Systems-BS 6701 ( Operates 50v d.c / Ringing Voltage in Excess off 80v a.c )

Mac I’ve got Problems with down Loading onto the Forum
My Sizing going to pot
An having to down load one at a time , and dropping it to size 8
PS can you see Dan ,

Sorry Caps I have to stop Down Loading stuff , Amberleaf

 

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Outgoing Circuits

An Rcd with a Residual Operating Current Not Exceeding 30mA is Recognised Device for Providing Additional
Protection in the Event of ,
1 , Electrical Fault ,
2 , Failure of Basic Protection ,
3 , Carelessness by the User or Operator ,
Such RCDs should Not be Used as Sole Means of Protection and do Not avoid the need to Apply one or more of the Protective Measures ,
Detail in the Regulations ,
Under the New Regulations , an Installation is Required to Incorporate One or More RCDs Depending on the Circumstances ,

The Regulations Affecting RCD Protection

411.3.3
Additional Protection by Means of a 30mA RCD is to be Provided for all Socket-Outlets with a Rated Current Not
Exceeding 20A for Use by Ordinary Persons ,
The Only Exceptions Allowed are for Socket-Outlets for Use Under the Supervision of “ Skilled “ or Instructed Persons e.g.
Some Commercial / Industrial , Locations or a Specifically Labelled Socket Provided for Connection of a Particular
Item of Equipment , Such as Freezer ,

701.411.3.3
In Specific Locations such as those Containing a Bath or Shower there is Now a Requirement to Provide RCD Protection
On all Circuits , Including Lighting and Shower Circuits ,

314.1 & 2 / 531.2.4
Every Installation should be Provided into Circuits as Necessary to Avoid and Minimise Inconvenience in the Event of a Fault ,
Designers are Required to Reduce the Possibility of Unwanted RCD Tripping due to Excessive Protective Conductor Currents
But Not due to an Earth Fault ,
Separate Circuits’ may be Required for parts of the Installation which need to be Separately Controlled in such a way
That they are Not Affected by the Failure of other Circuits ,
The Appropriate Subdivision should take Account of any Danger arising from the Failure of a Single Circuit ,
RCD Trip Causing the Disconnection of an Important Lighting Circuit ,

522.6.7
Much Greater Use of RCD is Required to Protect Wiring Concealed in Walls or Partitions , even where this is Installed
In Previously Defined Safe Zones ,
This Effectively means that all Concealed Wiring at a Depth of Less than 50mm from the Surface now Requires
Protection by 30mA RCD Unless Provided with Earthed Mechanical Protection ,

RCBO BS-EN 61009-1 is a Combination of an MCB & RCD This Enables Both Overcurrent Protection & Earth Fault Current protection and detection
Protection by a Single Unit

IP Rating , RCBO Front Plate IPX4 / Screw IPX2 ←

These may be Operated with our without Overcurrent Protection ( RCBOs )
With Single Pole RCBOs , even when they have Tripped , the Neural Wire is still Not Interrupted ←←
The RCBO will Trip and Cut off Power ,

RCCBs BS-EN 61008-1
Voltage Dependent RCCBs are Reliant on the Line Voltage to Trip the Switch through an Electronic Control Device ,
RCCBs
Provides Protection Against Earth Faults Occurring in Equipment and Reduces the Effects of Electrical Shock ,
RCCBs Measures the Current Flowing in the Line & Neutral Cables
And if there is an Imbalance , that is Current Flowing to Earth above the RCCB will Trip and cut off the Supply

Selection of conductors’ for Current Carrying Capacity & Voltage Drop
Are the Cables the Correct size for the Current which they have to Carry and is the Voltage Drop
In the Circuit below the Permitted Value ,
Regulations 523 / 524 / & 525 – part 4 ,

Erection Methods
Has the Installation been Erected to Comply with BS07671 Part 5

Regulations table 4A1 , appendix 4 & 522 ,
Correct Type of Installation to Suit Environment , Standard of Workmanship and Suitability of Fixings ,

Routing of Cables and in Prescribed Zones or within Mechanical Protection
Regulations 522.6 BS7671 & 7.3 OSG , Intended for use when Completing an Electrical Installation Certificate ,
Only Limited Inspection would be Possible during a Periodic Inspection Report ,

Connection of Conductors
Regulations 526 . Check for Tightness & Correct use of Terminations at a Random Selection of Accessories and all Distribution Boards ,

Presence of Fire Barriers , Suitable Seals & Protection against Thermal Effects
Reg , chapter 42 & section 527 ,
This is to Ensure that Structural Fire Barriers are not broken During Installation ,
Fire Barriers are Present in Trunking & Ducting where Required , and Intumescent hoods on Lighting where
Installed in Fire Rated Ceilings , Heat from Installed Equipment must Not be Likely to Cause a Fire ,
Particularly , Check that backless Accessories such as wall Lights and Electrical Enclosures are Installed
On Surfaces Suitable for Surface Temperatures & Radiated heat of Equipment

General ,
Presence and Correct Location of Appropriate Devices for Isolation and Switching ,
Reg , chapter 53 sec 7 Isolators Identified where not Obvious ,
Local and Under the Control of user or , if Remote , they must be Lockable and Identified Isolation of Fans with Timers Controls
In Bathrooms ( table 53.2 p-117
For Correct Selection of Devices ,

“ Periodic Inspection Report “

This Document is Used to Record the Condition of the Installation In Particular , is it Safe to Use ,
It is , however , Important that the Person Carrying Out the Inspection and Test is Competent ,

This Report must Also include a Schedule of Test Results and a Schedule of Inspection ,

A Periodic Inspection Report is Carried Out for Many Reasons ,
(i) The Due Date ,
(ii) Clients / Customers Request ,
(iii) Change of Ownership ,
(iiii) Change of use , Insurance Purposes
To Inspect the Condition of the Existing Installation , Prior to Carrying out any Alterations or Additions ,

The Frequency of the Periodic Inspection and Test is Dependent on the Type of Installation ,
The Environment and the Type of Use , BS 7671 Wiring Regulations refer to this as the ,
( Construction , Utilization and Environment )
Appendix 5 BS 7671 ,

Guidance Note 3
For the Inspecting & Testing of Electrical Installations has a Table of Recommended Frequencies for Carrying Out
Periodic Inspection & Tests / The Period Depends on the Type of Installation ,
The Recommended Frequencies , it is the Responsibility of the Person Carrying Out the Periodic Inspection & Tests
To Decide on the Period between Tests ,
This Decision should be Based on the Inspectors Experience ,
What the Installation is Used for ,
How Often it is Used , The Type of Environment that Surrounds the Installation ,
Many Others should be Taken into Account when Setting the Next Test Date ,

It is Important to Remember that the Date of the First Inspection & Test is set by the Person Responsible for the Installation Design , ( Change of Use or Ownership )

Careful Consideration must be Given to the Installation before the Date of the Next Periodic Inspection & Test is Set , ←←←←
It is Very Important that the Extent and Limitations of the Inspection and Test is Agreed with the Person Ordering the Work
Before Commencing Work ,

Before the Extent and Limitations can be Agreed , Discussion between all Parties involved must take Place , ←←←←
The Client will know why they want the Inspection Carried Out and the Person who is Carrying Out the Inspection and Test should have the Technical Knowledge and Experience to give the Correct Guidance ,

Test Results , Electrical Installation , / Periodic Inspection Reports
Fuse , Charts etc must be Made Available to the Person Carrying out the Inspection & Test , ←←←

If these are Not Available , then a Survey of the Installation must be Carried Out to Ensure that the Installation is Safe
To Test and to Prepare the Required Paperwork , such as Fuse Charts ,

Whist Carrying Out a Periodic Inspection & Test it is Not a Requirement to take the Installation Apart ,
This Should be Carried Out with the Minimum of Intrusion ,
Disconnection should Only be Carried Out when it is Impossible to Carry Out the Required Test
In any Other way , if an Insulation Résistance Test is Required on a Lighting Circuit with Fluorescent Lighting Connected to it ,

Would be to Open the Switch Supplying the Fluorescent Fitting before Testing between the Live Conductors ,
And Close the Switch when Conducting the Test between Live Conductors and Earth ,
It is Not a Requirement to Disconnect the Fitting
( Insulation Résistance Testing , Chapter 4 )

 

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Supply , Characteristics , Earthing & Bonding Arrangement
Supply , Characteristics , Nominal Voltage of the Supply
System Type TT . TN-S or TN-C-S ,

Nominal Frequency , Normally 50Hz , 110.1 ( xv )

● Prospective Fault Current ,
The Highest Current that could Flow within the Installation between Live Conductors , or Live Conductors & Earth ,
This should be Measured or Obtained by Enquiry , if Measured , Remember that on a ( 3 ) Phase System
The Value between Phase & Neutral must be Doubled ←←←

● External Earth Loop Impedance , ( Ze ) this is the External Earth Fault Loop Impedance Measured between the
Phase & Earthing Conductor for the Installation ,

Characteristics of the Supply Protective Device ,
● BS- Type , can Normally be Found Printed on the Service Head ,
● Nominal Current Rating , can Normally be found Printed on the Service Head ,
● Short-Circuit-Capacity , this will Depend on the Type , If in Doubt Reference / T- 7.4 OSG ,
● Main Switch or Circuit-Breaker , Type is Normally printed on it , ( Appendix 2 – BS-7671 if Required )
● Number of Poles , Does the Switch Break all Live Conductors when Opened ( or is it Single-Pole Only )
● Supply Conductor Material & Size , ( Refers to Meter Tails )
● Voltage Rating , ( this will Usually be Printed on Device )
● Current Rating , ( this will Usually be Printed on Device )
● RCD Operating Current , ( I∆n ) this is the Trip Rating of the RCD & should Only be Recorded if
The RCD is Used as a Main Switch )
● RCD Operating Time at ( I∆n ) Only to be Recorded if the RCD is Used as Main Switch ,
Means of Earthing ,
Distributors , Facility or Earth / Electrode ,
Type , if Earth / Electrode ,
Electrode Résistance , Usually Measured as ( Ze )
Location , where is the Earth / Electrode ,

Method of Measured ,
Has an Earth Fault Loop Tester or an Earth / Electrode Tester been Used to Carry Out the Test ,
To do this Test Correctly , the Earthing Conductor shall be Disconnected to Avoid the Introduction of Parallel Paths ,
This will of Course Require Isolation of the Installation ,
In some Instance this May Not be Practical or Possible , ( for Reasons )

If Isolation is Not Possible , the Measurement should still be Carried Out to Prove that the Installation has an Earth ,
The Measurement Value of ( Ze ) should be Equal to or Less than any Value for ( Ze ) Documented on Previous
Test Certificates ,
If the Measurement is Higher than those Recorded before , then Further Investigation will be Recorded ,

The Higher Measurement could be Caused by Corrosion ,
Loose Connection / or Damage ,

If the Means of Earthing is by an Earth Electrode ,
The Soil Conditions may have Changed , this would be Considered Normal Providing that the Measured Value
Is Less than ( 200Ω ) 411.5.3 Note 2 ,
And the systems is Protected by a Residual Current Device ,

Main Protective Conductors

Earthing Conductor
Conductor Material , What is it Made of ,
Unless Special Precautions are Taken in Accordance / BS-7671 ( this should be Cooper )

Conductor Cross-Sectional Area
This must Comply with Regulation Sec / 543 ,
If the System is PEM then Regulations 544.1
In most Domestic Installation’s this will Require ( 16mm2 ) further Information / 4.1 OSG ,

Continuity Check
This Requires a tick Only and is Usually a Visual Check ( Provided that the Conductor is Sound )

Main Equipotential Bonding Conductors ↔ ( Main Protective Bonding Conductor ) Regs p-32
Conductor Material
What is made of ,
Unless Special Precautions are Taken in Accordance / BS-7671 ( this should be Cooper )

Conductor Cross-Sectional Area
Must Comply with Regulations 544.
In Most Domestic Installations the Required Size is ( 10mm2 )
Information Available ( T – 10A / OSG )

Bonding of Extraneous Conductive Parts ,
All Services , Structural Steel , Lighting Conductors’ & Central Heating Systems should be Equipotential Bonded ↔ ( Main Protective Bonding Conductor ) Regs p-32
Regulations 411.3.1.2 ( Chap 4 - OSG
Normally a Tick Required ,

Sorry Chaps am going to Spec Savers ( PME , Protective Multiple Earthing

Correct Selection of Protective Devices

When Carrying Out an Inspection & Test on any Electrical Installation it is Important to Ensure that the Correct Size
And Type of Device has be Selective and Installed
Selection of Protective Devices and the Type of Circuits that they are Protecting ,

Protective Devices are Installed to Protect the Cable of the Circuit from Damage
This could be Caused by Overload / Overcurrent & Fault Current ,
( Overcurrent Occurring in a Circuit which is Electrically Sound ,
( Overcurrent is a Current Flow in a Cable which is Greater than the Rated Current-Carrying-Capacity of the Cables )
( Fault Current is a Current which is Flowing in a Circuit due to a Fault )

Will the Device be able to Safely Interrupt the Prospective Fault Current which could flow in the Event of a Fault
OSG. 7.4 or the Manufacturers Literature will Provide Information on the Rated Short-Circuit-Capacity of Protective Devices ,

Selection of Electrical Equipment ( Domestic Electricians 2392-10 )
133.1.1
Every item of Equipment shall Comply with the Appropriate British Standard ,
In its Absence of an Appropriate British Standard , Reference shall be Made to the Appropriate IEC Standard
Or the Appropriate National Standard of Another Country ,
133.1.2
Where there are No Applicable Standards , the Item of Equipment Concerned shall be Selected by Special Agreement between the Person Specifying the Installation and the Installer ,
133.1.3
Where Equipment to be Used is Not in Accordance with Regulation 133.1.1 or is Used Outside the Scope of its Standard ,
The Designer or Other Person Responsible for Specifying the Installation shall Confirm that the
Equipment Provides at Least the Same Degree of Safety as that Afforded by Compliance with the Regulations ,

Appendix 2 of BS-7671 Covers Statutory Regulations

Testing

To Ensure No Danger to Persons & Livestock and that No Danger Occurs to Property ,
To Compare the Results with the Design Criteria
Take a View on the Condition of the Installation and Advise on Any Remedial Works Required ,
In the Event of a Dangerous Situation ,
To Make an Immediate Recommendation to the Client to Isolate the Defective Parts ,

To Ensure the Fault is Repaired and Retest Any Parts of The Installation which Test Results May have been Affected by the Fault ,

A Circuit Breaker is Really two Devices in One Unit ,
The Overload part of the Device is a Thermal Bi-Metal Strip ,
Which heats up when a Current of a Higher Value than the Nominal Current Rating ( In ) of the Device Passes through it ,

Also Incorporated within the Device is a Magnetic Trip ,
Which Operates and Causes the Device to Trip when a Fault Current Flows through it
For the Device to Operate Correctly it must Operate within 0.1 seconds
The Current which has to flow to Operate the Device in the Required time has the Symbol ( Ia )

B Type MCBs
Should be Used on Circuits having Only Resistive Loads ,
C Type MCBs
Used for Inductive Loads such as Fluorescent Lighting , Small Electric Motors & other Circuits Where Surges could Occur ,
D Type MCBs
Used on Circuits Supplying Large Transformers or any Circuits where High Inrush Currents could Occur

Adequacy of Access to Switchgear and Other Equipment
Regulations 412.2.2.3 / 513.1 / 526. 3 / 537 / 543 / 559.10.3.1 (iii) OSG, 8.4
Doors of Enclosures must be Removable or able to be fully Opened ,
Access to Equipment should not be Obstructed ,
Cooker control switches within 2 meters of cooker & hob , app 8 , 8.4 OSG

Connection of Single Pole Devices for Protection and Switching in Line Only ,
Regulations 530.3.3 / 612.6
Switches in Phase and not Neutral Conductors, Generally Carried out when Continuity of CPC Tested along with a Visual Check ,

Correct Connection of Accessories & Equipment
Regulations 52 , section 6 Correct and Neat Connection ,
Look for Excessive Exposed Conductors , Cores of Cables not cut out where Terminal full ,
For Connection of fine wire Cables 526.8

Selection of Equipment & Protective Measures Appropriate to External Influences
Appendix 5 Regulations 512.2 chapter 52 sec 2
Check for the Suitability of a Wiring Systems for the Environment and Type of use to which it is being put
For Outdoor Lighting Regulations 559.10.4. / 559.10.5.1

Selection of Appropriate Functional Switching Devices
Regulations 537.5.2 table 53.2 Correct Operation of Switches / Isolators , throughout Installation

4 Earths / in Domestic’s , 16mm2 , 10mm2 , Presence of Supplementary bonding , CPC in Cables ,

“ At the Consumer Unit “
Before you Start this must be Isolated ,
The Electricity at Work Regulations 1989 States that it is an Offence to Work Live
Once you Remove a Cover you will be Working Live if you do Not Isolate it First ,
Having Carried Out Safe Isolation Procedure , Remove the Cover of the Consumer Unit

Part P Domestic Electrical Installation Certificate
An Electrical Installation Certificate is Required for ,
● A New Installation ,
● When New Circuits are Installed ,
● When a Single Circuit is Installed ,
● The Changing of a Consumers’ Unit ,
● When a Circuit is Altered and the Alteration Requires the Changing of the Protective Device ,

 

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Domestic Electricians’
510.2 Every Item of Equipment shall be Selected and Erected so as to Allow Compliance with the Regulations Stated
In this Chapter and Relevant Regulations in Other Parts of BS-7671 and shall take Account of Manufacturers Instructions ,
511 Compliance with Standards
511.1 Every Item of Equipment Shall Comply with the Relevant Requirements of the Applicable British Standard
Or Harmonized Standard , Appropriate to the Intended Use of the Equipment ,
The Edition of the Standard shall be the Current Edition , with those Amendments Pertaining at a Date to be Agreed by
The Parties to the Contract Concerned ( App 1 )

511.1 Alternatively , if Equipment Complying with a Foreign National Standard based on an IEC Standard is to be Used
The Designer or Other Person Responsible for Specifying the Installation shall Verify that any Differences between that
Standard and the Corresponding British Standard or Harmonized Standard , will Not Result in a Lesser Degree of Safety than that Afforded by Compliance with the British Standard

511.2 Where Equipment to be Used is Not Covered by a British Standard Or Harmonized Standard , or is Used Outside the Scope
Of its Standard , the Designer or Other Person Responsible for Specifying the Installation shall Confirm that the Equipment
Provide the Same Degree of Safety as that Afforded by Compliance with the Regulations ( British Standard )
( Selection of Electrical Equipment ( 133.1.1 / 133.1.2 / 133.1.3 )

133.2 Characteristics ,
Every Item Electrical Equipment Selected shall have Suitable Characteristics Appreciate to Values and Conditions on
Which the Design of the Electrical Installation , @

Domestic Electrical
( Zs ) is the Earth Fault Loop Impedance ( Zs = Ze + R1 + R2 ) ( Zs ) is the Measurement of the Whole Fault Path R1 + R2 ) Measurement of the Circuit of Installation then ( Zs ) then has to be Low Enough to Allow Current to Flow in Order for the Protective Device to Operate New Installation , ( Values off 80% OSG T-2D ( Electrical Installation Certificate Regs – p-334 ) 1st ← ← Maximum ( Zs ) ( Values off 100% Regs – p-41.3 ( Ze ) PFC ↔ Test ( 230 ÷ 0.04 = 5750Ω , Calculation ( 6kA ) PSCC Test Across Live / Neutral , 434.5.1 PFC is Between Live / Earth ( you have Measured PFC ) PFC is the Highest of the Two Readings ( Noted on Test Cert , PSCC Prospective Short-Circuit Current ( L / N PFC Prospective Fault Current ( L / E ( Zs )

 

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Sorry Chaps Jason going to have My Cuts for Carters , ( Jason will be on Prozac )
“ Documents “ ● Electricity at Work Regulations 1989 - Statutory ● IEE Guidance Note 3 – Inspection & Testing – Non- Statutory ● BS-7671 Requirements for Electrical Installations – Non- Statutory ● IEE Onsite Guide - Non-Statutory ● HSE Guidance Note GS38 - Statutory
● Next Inspection on Domestic Premises = Maximum - Ten Years , ● The age of the Installation , Change of use, Request of Insurers, Change of Ownership, Following Damage, etc,
“ New Cooker Circuit “ ● Certification / Documentation , ● Electrical Installation Certificate ● Schedule of Inspections ● Schedule of Test Results A New Circuit has been Installed back to the Origin ( Cooker ). This Requires an Electrical Installation Certificate. On replacing the Consumer Unit, you are changing the Protective devices and need to Confirm that Existing Circuits are Adequately Protected and Conform to BS-7671 ,
“ Test schedule “ ● Schedule of Inspections , ● Test Instrument Details ● Make and Model ● Serial Number ● Type of Supply / Earthing Arrangements , Regs , p-32 ● External Earth Loop Impedance – ( Zs ) ● Prospective Fault Current ( PFC ) 612.11
● Routing of cables in prescribed zones ● Selection of conductors for current carrying capacity ● Erection methods ● Presence and Correct Location of Appropriate Device for Isolation and Switching… Etc , ● Practical problems , ( Circuit Tails not Long Enough )
“ Test sequence “ Cooker Circuit “ Tests “ GN-3 ● (1) Continuity of Protective Conductors 612.2.1 (1) Full sequence is given in Regulation 612.2.1.
● Insulation Resistance ● Polarity (usually in conjunction with (1) 612.6 ( Dead Test )
GN-3 ● Earth Fault Loop Impedance , ( Live Test ) 612.9 ● Operation of Switch / Isolator , ( Functional Testing ) 612.13.2
“ Instruments “ ● Low-reading ohmmeter – Ohms , ● Insulation Resistance Tester – M W , ● Loop Impedance Tester – Ohms ,
“ Inspection & Test of Industrial Unit “ ● Periodic Inspection Report ● ( Referring to question ) Extent and Limitations of the Inspection ● The ‘Person Ordering the Work’ ( the Client ) ↔ Originals Retained by Client (‘Person Ordering the Work’ )
“ Minor Works Cert “ ● System Earthing Arrangements ●Type and Rating of Protective Device for Modified Circuit
“ Units “ ● mA (and ms) milli-A mps ( and milli-seconds ) “ Sequence of tests “ GN-3 ● Continuity of protective conductors ● Continuity of ring final circuit conductors ● Insulation Resistance ● Polarity

 

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“ Earthing / Bonding Terminology “ Regs , p-32 ● Main Earthing Conductor ● Circuit Protective Conductor ● Supplementary Protective Bonding Conductors ( where required )

“ IP Codes “ ● IP4X top Distribution Board , 416.2.2 ● IP2X or IPXXB side Distribution Board ● Domestic-Switchgear , by use of tool or key , ( 416.2.4 )

“ CPC Continuity Test “ ● Low Reading Ohmmeter / W - Ohms , ● Either Zero the meter with leads connected to each other, or record the resistance of the leads and deduct it from measurements. ● Last point (or highest reading) is the value of (R1 + R2) for the circuit

“ Ring Circuit Continuity “ ● Verify continuity of CPC. Confirm a Ring exists without ↔ Interconnections ↔ obtain values of R1 and R2 with which to compare Directly measure ( R1 + R2 )

“ Insulation Resistance “ MW - Mega-Ohms , “ Isolate Installation from Supply “ ≈ ● Remove all lamps ←← ● Disconnect all Sensitive Equipment – Dimmers , Neon’s , Fluorescents etc , ( a must ) ● Close all Switches ↔ ● Check test leads ↔ ● Set Meter tester to 500V d.c. ● Test between Live / Neutral - Live / CPC and Neutral / CPC , ≈ ● Lowest Reading Must be Greater than 2 MW. If a Lower Reading is Obtained then Circuits must be Tested Individually ,
“ Insulation Resistance of SELV and PELV Circuit “ 612.3.2 ● 250V d.c. ● ≥ 0.5 MW ● 500V d.c. ● ≥ 0.1 MW “ Insulation Resistance Values “ ● 0.00 MW = Dead Short , ● 0.08 MW = Low Insulation Resistance Fault , ● ≥ 200 MW = Healthy Circuit ,
“ Loop Impedance “
● To Determine that an Earth Fault path Exists and is low enough to allow Sufficient Current to Flow in the Event of a Fault to Operate the Protective Device within the Prescribed Times , ● Increase the size of CPC to bring it up to 17th Edition if needed ( The method is to use an RCD 30mA ) ● The Highest Zs Value is Recorded. ● The Earth Fault Loop Impedance must be low enough to comply with the Requirements of the Protective Devices in the New CCU. Also it is essential to Verify that an Earth Fault Path Exists before a Circuit is Connected to the New CCU ,

“ 30mA RCD “ mA (and ms) milli-A mps ( and milli-seconds ) ● For Operation of Portable Equipment Outside the Main Protective Bonding Conductor Zone , ● To meet Disconnection Times if Zs is too high , ● For fixed Equipment in Bathrooms , ● For all Sockets on a TT system ,

“ 500mA RCD Tests “ ● Apply 50% current (250mA) – RCD should not trip on either half-cycle , ● Apply 500mA (rated current) – RCD should operate within 300ms , ● Test ‘T’ button to verify Electro-Mechanical Operation. ( Functional Test ) 612.13

↔↔ Insulation Resistance Tester – M/Ohms ↔↔ the Ω Sign didn’t get through Sorry ( M W ) should be Ohms ←

“ Prospective Fault Current at origin “ ● Maximum Zs values given in Schedule of Test Results , ● In this case the Zs values must Be Calculated and this fact Noted on the Test Schedule ● The Type and Rating of the Distributors’ fusible cut-out or protective device , ● Basic Information Required , Nature of Supplies 313.1 / O.S.G p-13 , ● You’ll Need to Write this in your Schedule of Test Results , when your Finished the Testing on the Board(s)

 

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Electrical Installation Certificate

The Electrical Installation Certificate is to be Used Only for the Initial Certificate of a New Installation or for Alteration or Addition
To an Existing Installation where New Circuits have be Introduced ,

It is Not to be Used for Periodic Inspection for Which a Periodic Inspection Report Form should be Used ,
For Alteration or Addition which Does Not Extend to the Introduction of New Circuits ,
( a Minor Electrical Installation Works Certificate may be Used )

The Original Certificate is to be Given to the Person Ordering the Work ( 632.3 ) p-163
A Duplicate should be Retained by the Contractor ,

Electrical Installation Certificate
(i) the Electrical Installation Certificate Required by Part 7 shall be Made Out and Signed or Otherwise Authenticated by a
Competent Person or Persons in Respect of the Design ,

(ii) the Minor Works Certificate Required by Part 7 shall be Made Out and Signed or Otherwise Authenticated by a
Competent Person or Person in Respect of the Inspection & Testing of an Installation

(iii) the Periodic Inspection Report Required by Part 7 Out and Signed or Otherwise Authenticated by a Competent Person
In Respect of the Inspection & Testing of an Installation ,

(iv) Competent Persons will , as Appropriate to their Function Under (i) – (ii) – (iii) Above ,
Have Sound Knowledge and Experience Relevant to the Nature of the Work Undertaken and to the Technical Standards
Set Down in this British Standards ,
Be Fully Versed in the Inspection and Testing Procedures Contained in this Standard and Employ Adequate Equipment ,

(v) Electrical Installation Certificate will Indicate the Responsibility for Design ,
Construction , Inspection & Testing , whether in Relation to New Work or Further Work on an Existing Installation ,


Where Design , Construction and Inspection & Testing , is the Responsible of One Person a Certificate with s Single Signature
Declaration in the Form Shown below may Replace the Multiple Signatures Section of Mode Form

“ FOR DESIGN , CONSTRUCTION , INSPECTION & TESTING “

(iv) a Minor Works Certificate will Indicate the Responsibility for Design , Construction , Inspection & Testing
Of the Work Described in Part 4 of the Certificate

(vii) a Periodic Inspection Report will Indicate the Responsibility for the Inspection & Testing of an
Installation within the Extent & Limitations Specified on the Report

(vii) a Schedule of Inspections and a Schedule of Test Results as Required by Part 7 shall be Issued with the Associated
Electrical Installation Certificate or Periodic Inspection Report

(ix) when Making Out and Signing a Form on Behalf of a Company or Other Business Entity ,
Individuals shall State for Whom they are Acting ,

(x) Additional Forms may be Required as Clarification , if needed by No-Technical Person , or in Expansion , for Larger
Or More Complex Installation ,

(xi) the IEE Guidance Note 3 Provides Further Information on Inspection & Testing on Completion and for Periodic Inspections ,

2392-10
Options for Showing Electrical Installation Competence

The Following is Provided as a Guide to Different ways in which in any Electrical Work Undertaking can be Certified ,

(i) if an Approved Certifier of Construction has Carried Out Electrical Work then that Contractor will Provide the Appropriate
Certificate , Duly Completed , for the Council to Verify OR

(ii) if the Electrical Contractor or Electrician is Not an Approved Certifier of Construction then the Appropriate Certificate
Taken from BS-7671 2008 should be Submitted , Duly completed , Together with Evidence of Competency ( i.e. Valid ↔
JIB Card or having Current Membership of an Accredited Registration Scheme Operated by a Recognised Professional
Body e.g. NICEIC or Select or Equivalent Body OR

(iii) if the Electrical Work was Carried Out by a Qualified Electrician , it may be the Case that you will Need to have the
Installation Checked by a Qualified Electrician and the Appropriate Certificate in Accordance Submitted ,
With Evidence of Competency ( i.e. Valid JIB Card / or having Current Membership of an Accredited Registration
Scheme Operated by a Recognised Professional Body e.g. NICEIC or Select OR Equivalent Body ,

Testing Class II Equipment

The test includes:
• physical examination
• insulation test
• flash test (optional)
The first test conducted must be the detailed physical examination. Any faults found should be corrected and defective items replaced.
The first electrical test performed will be the insulation resistance test. If the appliance is double-insulated then the insulation test is carried out between the combined live and neutral pins on the plug and a probe that is applied to the outside of the appliance case. Make sure that the appliance under test is turned on. The resistance reading should be at least 2 M Ohms. If the resistance reading is less than the value you must investigate why. Do not use the appliance until the fault has been cleared.
Testing Class III Equipment
Class III equipment is designed to be supplied by a reduced voltage which is normally 110V. Portable Appliance Testers are usually rated to operate at 240V and manufacturers usually provide each model in two versions to be able to test class III apparatus separately.
APPENDIX 1
BS1363 - 13A plugs, switched and unswitched socket outlets and boxes.
BS2754 - Construction of electrical equipment for protection against electric shock.
BS2769 - Hand-held electric motor-operated tools.
BS3456 - Safety of household and similar electrical appliances.
BS3535 - Specification for safety isolating transformers for industrial and domestic purposes.
BS4343 - Industrial plugs, socket outlets and couplers for AC and DC supplies.
BS4533 - Luminaries’.
BS4743 - Safety requirements for electronic measuring apparatus. (IEC348).
BS5458 - Safety requirements for indicating and recording electrical measuring and their accessories.
BS5850 - Safety of electrically energised office machines. (IEC380).
BS6204 - Safety of data processing equipment. (IEC435). BS6500 - Insulated flexible cords.
BS7002 - Safety of I.T. equipment including business machines. (IEC950).
Note: The IEC reference is the International Electrotechnical Commission "parent" standard. For Appendix 2 & 3 please consult the "Electrical Safety Testing" booklet.

 

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Testing Class I Equipment

The tests include:
• physical examination
• earth bond test - essential
• insulation test - essential
• flash test - optional
• operation test - optional
• power consumption test - optional
A detailed visual inspection should be performed first and any faults corrected. Over 75% of all equipment defects can be found at this first stage. Hazards such as loose cable grips, plugs incorrectly fitted, unsafe cable joints, damaged cable, wrong value fuses or illicit fuses should all be discovered and corrected at this physical inspection stage before electrical tests are commenced.
Before performing the electrical tests, it is important to establish whether the appliance is a light current type. Assume the appliance to be light current if it has a 3 or 5A fuse fitted, if it has a power rating less than 1kW or if the appliance cable is thinner than the normal mains lead. If these criteria apply then the appliance tester will be operated in a different manner. The manufacturers instruction booklet should be referred to.
The first essential test for class 1 appliances is the earth bond test. This test is intended to ensure that the exposed metalwork on the appliance is securely connected to the safe earth potential. During the test a high current (up to 25A) is passed through a circuit comprising the appliance earth conductor of the supply lead, the exposed metal on the appliance and the temporary test lead from the appliance tester. If the exposed metal work is securely connected electrically to the conductor, the resistance of the above circuit will be low. To be acceptable it must be between 0 and 0.1 Ohms (0.5 Ohms for low current appliances). This test must be carried out on all exposed metal work. If the resistance is too high, the protection afforded by earthing will be limited.
If the reading on the appliance tester indicates a high resistance or the fail indicator lights, then this must be investigated. First check the logged value for the equipment. It may be a low current appliance. If the reading is the same as the previous recorded value then this may be accepted (the resistance of thin mains leads may be appreciable e.g. 2.5 metres of 0.5 sq mm cable is itself around 0.1 Ohms). A particularly long lead or extension cable may also have an appreciable resistance. If this is the case get advice as to whether a circuit breaker should be fitted.
Check the security of the connections in the mains plug although this should already have been done during the physical inspection. Do not progress with further tests until this fault has been cleared.
The second essential test for class 1 appliances is the insulation test. This is used to ensure that a breakdown of the insulation cannot occur between any live parts within the appliance and parts of the casing that the user may touch. The appliance tester must be able to deliver a 500V DC test voltage for all loads of 2 Mohms upwards. The test may be performed as many times as you like without causing undue stress to the appliance under test. Note that the test procedure is slightly different for class 1 and class 2 appliances.
The appliance under test is switched on. If the appliance is earthed then the insulation test is carried out between the earth pin and the combined live and neutral pins on the plug. This relies on a satisfactory result for the earth bond test. If the earthing is faulty this test should not be performed as the results would be totally invalid.
Although the essential tests must be carried out in the order described the optional tests may be carried out in any sequence, but the flash test should only be carried by fully trained personnel preferably under workshop conditions. If an appliance has been recently repaired the essential earth bond and insulation test must be repeated first then the optional test can be carried out. The optional tests, although straightforward, can be difficult to interpret and should therefore only be authorised, carried out and interpreted by highly skilled and preferably electrically qualified personnel.

What type of Equipment Should be Tested

The equipment to be tested will normally be constructed in one of 3 basic classes designated Class I, II or III under British Standard 2745. (Class O equipment which has no provision for the earthing of metalwork is of foreign origin and safe only in earth-free zones.
Class I Apparatus is provided with basic insulation. In addition the metalwork is earthed so that it cannot become live in the event of an insulation failure.
Class I Apparatus is the most common type; its safety depends on the integrity of its one layer of insulation and the earth bonding of its metalwork. If there is an insulation fault, the metalwork is entirely dependent on the integrity of the earth bonding if it is not to attain a hazardous voltage. Inspection of the earthing conductors and connections is very important where this type of apparatus is used.
Class IIA (All-insulated) Apparatus has two layers (or equivalent) of insulation, one of which covers or comprises the outer casing so that metalwork cannot be touched. Class IIB (Double-insulated) Apparatus has all exposed metalwork separated from the conductors by two layers of insulation so that the metalwork cannot become live. There is no earth connection and the operator's safety depends on the integrity of the two layers of insulation. The first layer is basic or functional insulation and the second layer is supplementary or protective insulation. In some cases a single insulation layer is allowed if it is mechanically and electrically equivalent to double insulation.
Class II equipment is marked with the symbol (please consult "Electrical Safety Testing" booklet for symbol).
Class III Apparatus operates on safety extra low voltage (SELV) i.e. at a voltage not exceeding 50V AC between conductors or to earth. The apparatus has basic insulation only and unearthed metalwork.
Class III motor operated tools are not widely used in the UK as they are difficult to obtain. They are larger than comparable mains voltage tools and larger cables have to be used to avoid volt drop problems. 50V or 25V handlamps, soldering irons and special purpose heaters are commonly used.
While the isolating transformer provides the essential electrical separation from the mains supply, some users also choose to earth the centre tap of the low voltage winding of the transformer and also earth the exposed metalwork of the apparatus. This is strictly speaking a Class I extra low voltage installation with a line-earth voltage of half the system voltage.
Class III equipment should not be fitted with plugs or connectors of a type standardised for operation at mains voltage.

 

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Priority Equipment and Equipment with Special needs

When instituting a test programme, priority should be given to certain types of equipment whose usage and operational environment mean that they are more likely to give rise to electrical danger. Examples of these include the following:
• Handheld tools such as drills.
• Equipment with long cables which might be easily damaged and those with easily damaged electrical components e.g. floor polishers, vacuum cleaners, desk lamps.
• Equipment with which water is intimately involved e.g. kettles, steam irons, thermostat baths, water stills, electrophoresis apparatus.
• Equipment normally used in a wet or humid place e.g. in kitchens, hot rooms, cold rooms, aquaria, hydraulics laboratories.
• Equipment used in areas where there is a high chance of damage by corrosive chemicals, oils, solvents or sunlight. These are especially liable to damage the insulation.
• Equipment used outdoors.
Extension leads should be treated in a similar fashion to removable mains leads. They should have unique serial numbers and be tested at regular intervals. The following tests are recommended:
1. Resistance of the earth conductor.
2. Insulation resistance testing.
3. Continuity of each conductor.
4. Polarity of phase, neutral and earth connections.
As the length of the extension cable will have an effect on earth resistance, compare the test value with the resistance expected for the particular conductor size. Extension leads are likely to be exposed to a high level of abuse. Visual inspection of the insulation is therefore extremely important as is examination of the terminations to the plug and socket.
Modern low voltage transformers are manufactured to British Standard 3535 which allows either Class I or Class II construction. The transformer should be treated as any other piece or portable equipment. An additional test may be required to ensure that the primary voltage does not appear on the secondary winding. A flash test conducted on a Class I transformer will have additionally proved the insulation between the primary winding and the earthed screen thus ensuring primary/secondary isolation. The flash test conducted on a Class II transformer will not have tested the integrity of the insulating barrier between primary and secondary winding. A high voltage insulation test will therefore be required between the input and the output connections.
Portable Appliance Testers are in themselves items of portable equipment and will therefore require safety testing in accordance with the criteria described elsewhere in this booklet. In addition, the equipment should be subjected to a full certified calibration procedure on an annual basis.
There are some common types of equipment which are not connected to the electrical system by a 13A plug but which are nevertheless the responsibility of the Department. Examples are centrifuges, electron microscopes, X-ray equipment and workshop equipment such as milling machines and lathes. Special arrangements, in some cases with the supplier, will be necessary to deal with these items. The fact that they are not portable (nor indeed readily transportable) may mean that testing can be carried out less frequently but the location and usage does need to be considered.

Frequency of Testing

There are no absolute rules regarding how often an item of electrical equipment should be tested. The Health and Safety Executive Guidance Notes on the safety of electrical apparatus advise "regular testing" and this is generally interpreted as a requirement for annual testing. However, circumstances and conditions of use will vary and it is therefore up to Departments to assess the conditions of use of each piece of apparatus to determine, using the following guidelines, the test regime which is most appropriate.
The criteria which should be used to assess the need for testing the equipment includes the following:
1. Whether the equipment is portable i.e. Is it always used held in the hand (as opposed to being transportable) so that there is a greater likelihood of the apparatus being dropped while is use as opposed to being permanently installed on a desk.
2. Whether its usage is continuous or infrequent and whether the nature of its task is inherently rough.
3. The age of the equipment.
4. If the equipment is regularly moved or transported and by what means.
5. The overall competence of personnel using the equipment.
6. The environment of usage i.e. indoors v outdoors, hazardous atmospheres, likelihood of exposure to water, solvents, oils etc.
7. The results of previous tests.
Based on these criteria some suggested test periods are as follows:
Handheld portable tools should be tested every 6 months.
Equipment identified as being a priority should be tested not less than once every 12 months.At least 25% of double insulated (class II) equipment should be tested each year with the aim of testing each piece of this type of apparatus every four years.
Within this general framework, most equipment in laboratories or workshops should be tested at intervals of between 12 and 24 months, depending on the 7 criteria listed above. Most equipment in offices, libraries and similar accommodation should be tested every 24-36 months.

Test Precautions

The safety test programme consists of each item of apparatus receiving a visual inspection, essential tests (earth bond and insulation) and in some cases, additional tests such as flash, operational and earth leakage tests. Of the essential tests, the insulation test is always carried out but the earth bond test in only performed on class 1 appliances. The optional tests should be performed at the discretion of the competent person in charge, perhaps because there is some reason to think the appliance may become unsafe. Some optional tests should not be carried out more than is necessary as they may weaken the insulation of the appliance.
The following precautions are necessary during the testing of the apparatus:
1. Precautions for Essential Tests
• Check the test results sheet and identify the class of the appliance, its operating voltage and any special precautions which should be observed.
• Check that the environment in which the tests are to be performed is free from hazards, e.g. the earth bond test or insulation test may produce a spark which would ignite flammable vapours or fine dust.
• Disconnect all other equipment from the appliance under test. This not only guards against potential hazards but also against spurious results.
• Ensure that no one including yourself touches the appliance during testing. If the appliance is faulty they may receive an electric shock.
• Ensure that any test equipment is plugged into a proper earthed mains supply.
• Some tests require that the appliance under test is switched on. You may need to clamp the on/off button on some appliances. Ensure that no damage is possible due to the operation of the appliance e.g. an electric drill would need to be suitable secured during the test.
• Stop testing immediately an appliance fails one particular test. Do not go on to the next test because the appliance may be in a dangerous state.
• Always do the tests in order of, first, visual inspection then the earth bond test for class 1 appliances followed by the insulation tests.
2. Precautions for Optional Tests
All the precautions above apply to the optional tests plus those give below:
• Check the initial test results and ensure that any given test may be applied to the appliance. Electronic equipment may use semi-conductor devices and interference suppressors which will not withstand certain tests. The equipment manufacturer should be asked to define which tests may not be undertaken. Motors such as inductively stalled types will not pass the low voltage load test.
• Take particular care when performing a flash test as the very high voltages can be dangerous. It is best to have a second person on hand so that if you receive a shock, they can remove the power and resuscitate you.

4. After an initial physical evaluation, electrical tests are carried out to ensure the continued safety of each appliance. The test results are logged. Equipment which fails a safety test is withdrawn from use, the cause investigated and it is either repaired or replaced.

'Wattage' of Equipment = Fuse Rating
'Wattage' of Equipment Fuse Rating
Up to 600 Watts 3 Amps
Between 600 Watts and 1000 Watts (1KW) 5 Amps
Between 1KW and 3KW (3000 Watts) 13 Amps

Equipment that is rarely moved and is not at risk of damage (e.g. computers) is likely to be low risk and requires less frequent inspection than equipment that is frequently moved, might be used in a damp environment (e.g. kettles, water baths) or may be subject to damage.
Equipment used in an office environment is rarely of the type that would be considered high risk. High risk equipment includes equipment such as portable electrical hand tools.
As the title visual inspection implies, all you really need to do is look closely at the equipment. More than 90% of equipment faults can be found by visual inspection.

Current Fire Extinguisher Colour Codes ( New EEC Colures / BS- )

(1) Just ↔ Red ( Water Only ) ↔ Water
● Paper , Wood , Textiles & Solid Materials Fires

(2) Red ( With Blue Mark on Red Body ) ↔ Powder
● Liquid , Electrical , Wood , Paper & Textile Fires

(3) Red ( With Cream Mark on Red Body ) ↔ AFFF Foam
● Liquid , Paper , Wood , Textile Fires

(4) Red ( With Black Mark on Red Body ) PS. Do Not Hold Horn When Operating ↔ Carbon Dioxide ( CO2 )
● Liquid , Electrical Fires ,

N.B (a) Both Colour Codes are Still in Use ,
(b) a New Class F Extinguisher is now Available for Cooking Oil & Fat Fires ,

 

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That’s how to Keep the Reaper at Bay !!!!!

Isolation

(1) Remove the Load from the Circuit to be Isolated
(2) Open the Isolator and Lock Off
(3) Prove the “ Approved Voltage Tester “ on a Know Source ( Proving Unit )
(4) Test the Circuit to Confirm as “ Dead “
(5) Re-Prove the “ Approved Voltage Tester “ on the Proving Unit
(6) Fit Warning Notices at the Point of Isolation
(7) Keep the Key in your Pocket Ensuring Only you can Re-Energise the Circuit

The Source of Supply may Not have Means of Locking Off Afforded to it ,
If that is the Case , Look for Alternatives , Lock the Whole Switch Room Off if Necessary ,
Physically Disconnect the Supply , if you Have to Leave a Lookout at the Point of Isolation ,

Inform People of What you are Doing ,

→ → Your Safety is Your Own Responsibility ← ←

The Above May or Not be Factual ,
The Point is Every Time an Electrician is Electrocuted it is Because the Correct “ Isolation Procedure “ has Not been Followed ,

Continuity of Protective Conductors
612.2.1
Instrument ( Continuity Tester ) Low Ohms
No Load Voltage between 4 & 24V d.c. or a.c.
Short-Circuit Current of Not Less than 200mA Ia / Ief ( Exposed Conductive Parts )

On New Installations’ or where the Supply may be Isolated then the Protective & Bonding Conductors’ May be Disconnected for the Duration of the Test
Where this is Not Possible Earth Loop Impedance Tests may be Made to Verify Continuity ,
Instrument , Main Protective Bonding Conductor , Cables Résistance should Not Exceed 0.05Ω
The Résistance of a Typical Supplementary Protective Bonding Conductor Should Not Exceed ( R = 50 V ÷ Ia )

411.8.3
“ Requirements for Fault Protection “

Where Fault Protection is Provided by an RCD , the Product of the Rated Residual Operating Current ( I∆n )
In Amperes and the Earth Fault Loop Impedance in Ohms shall Not Exceed 50 V

“ Circuit Protective Conductor “
Does Not Rise Above Earth Potential More than 50V ,

Overcurrent Protective Device is Used , Zs / Uo ÷ Ia ( 230 ÷ Amp = Zs )

Damage Under Earth Fault Conditions “ Ohms “ Ia / Uo ÷ Zs ( 230 ÷ Zs = Amp )

Requirements Relating to Items Required for Typical Distribution Board Schedule 514.9

Domestic Electrician Installation of Cables , 521.10.1 , Meter Tails ( IP4X )
434.3 / (iv) Csa 514.3 530.3.4 - Consumers Controlgear ,

527.2.1 / FireFoam ( fire-resistance

120.3
Any Intended Departure from these Parts Requires Special Consideration by the Designer of the Installation and Shall be
Noted on the Electrical Installation Certificate Specified in Part 6 ( Inspection & Testing )
The Resulting Degree of Safety of the Installation shall be Not Less than Obtained by Compliance with the Regulations ,

132.13
Documentation for the Electrical Installation
Every Electrical Installation shall be Provided with Appropriate Documentation , Including that Required by
Regulation 514.9 , Requirements Relating to Items Required for Typical Distribution Board Schedule , Part 6 & where Applicable Part 7

134.1.7
Where Necessary for Safety Purposes , Suitable Warning Signs and / or Notices shall be Provided

610.1 Initial Verification ( Testing for New Electrical Installation Work )
Every Installation shall , During Erection and on Completion before being put into Service , be Inspected & Tested to Verify ,
So far as is Reasonably Practicable , that the Requirements of the Regulations have be Met

134.2.1
Initial Verification ( Initial Inspection & Testing )
During Erection and on Completion of an Installation or an Addition or Alteration to an Installation ,
And before it is put into Service , Appropriate Inspection & Testing shall be Carried Out by Competent Persons to Verify
That the Requirements of this Standard has been Met ,

( Appropriate Certification shall be Issued in Accordance with Sec 631

631.1
Upon Completion of Verification of a New Installation or Changes to an Existing Installation , an Electrical Installation Certificate
( based on model given in App 6 p-331 , shall be Provided , Such Documentation shall Include Details of the Extent of the
Installation Covered by the Certificate , Together with a Record of the Installation and the Results of Testing
( Schedule of Inspection and Electrical Installation Certificate )

Paperwork that should be Issued on Completion of New Installations ,
Schedule of Test Results , Schedule of Inspection & Electrical Installation Certificate

632 Initial Verification
632.1
Following the Initial Verification Required by Chapter 61 p-155 an Electrical Installation Certificate together with a
Schedule of Inspection , Schedule of Test Results , shall be given to the Person Ordering the work

632.2
The Schedule of Test Results shall Identify Every Circuit , Including its Related Protective Device(s) and shall
Record the Results of the Appropriate Tests and Measurements ,
632.4
Defects or Omissions Revealed During Inspection & Testing of the Installation Work Covered by the Certificate shall be Made
Good before the Certificate is Issued , ← ←

611 Inspection
611.1 Inspection shall Precede Testing and shall Normally be Done with that Part of the Installation Under Inspection Disconnected
From the Supply , ( That Appropriate form of Disconnection is Isolation )

Regulation 12 Electricity at Work Regulations 1989

( Maximum Demand & Diversity should be Determined before an Installation is to begin ) ←←

311 Maximum Demand & Diversity
311.1 For Economic & Reliable Design , the Maximum Demand of an Installation shall be Assessed
In Determining the Maximum Demand of an Installation or Part thereof , Diversity may be taken into Account ,

314.4
Where an Installation Comprises more than One Final Circuit , each Final Circuit shall be Connected to a Separate Way
In a Distribution Board , the Wiring of each Final Circuit shall be Electrically Separate from that of Every Other Final Circuit ,
So as to Prevent the Indirect Energizing of a Final Circuit Intended to be Isolated ,
( This is a requirement in Domestic ) ←← Part P ,

 

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● “ Continuity of Protective Conductors “ ( Dead Test ) ( Guides Note -3 ) GN-3

Instrument , Continuity Tester ( Set on Low Ohms Scale )
( Multimeter can be Used to Measure the Voltage between two Positions )

612.2.1 No Load Voltage between 4 / 24V
Short Circuit Current of not Less than 200mA ( Ia Ief )

Earth Loop Impedance Test to Verify Continuity ( Measures Résistance of Conductors’ )

● “ Continuity Ring Final Circuit Conductors “ ( Dead Test )

Instrument , Continuity Tester ( ( Set on Low Ohms Scale )

612.2.2 No Load Voltage between 4 / 24V
Short Circuit Current of not Less than 200mA ( Ia Ief )

(1) Test is Undertaken to Ensure that all Conductors of the Ring Final Circuit are Continuous ,
(2) Conductors’ have Not been Bridged Creating Multiple Loops ,
(3) That all Connections are Electrically and Mechanically Sound ,

Step 1 , Isolated and Disconnected from The Supply

Step 2 , Phase & Neutral Conductors are Now Cross Connected so that the Outward Leg of the Phase Connects to the
Neutral and the inward Leg of the Phase Connects to the Outward Leg of the Neutral
Readings are Now taken between Phase and Neutral at each Socket
Readings at each Socket Outlet should be within 0.05Ω of each Other
(i) Failure to be within this Limit would Highlight Loose Terminations
(ii) Significant Increase at a Socket would Indicate that it is a Spur , Bridges within the Circuit would be Indicated by a
Gradual Decrease on the Return Leg

Step 3 , Phase & CPC Loops are now Interconnected so that the Outward Leg of the CPC Connects to the inward Leg
Of the Phase and the inward Leg of the CPC Connects to the Outward Leg of the Phase ,

(iii) Measured Value may be Recorded as ( R1 + R2 )

● “ Polarity “ ( Dead Test )

Instrument , Continuity Tester ( Set on Low Ohms Scale )

612.6 No Load Voltage between 4 / 24V
Short Circuit Current of not Less than 200mA ( Ia Ief )

It must be Confirmed by Test , Every Fuse and Single-Pole Control and Protective Device is Connected in the Line Conductor Only ,
612.6 (ii)
Contact Bayonet and Edison Screw Lampholder(s) have the Outer or Screwed Contacts Connected to the Neutral ,
The Phase Conductor is Connected to the Centre Termination of an Edison Screw Lampholder Only , ←←

612.6 (iii)
Wiring has been Correctly Connected to Socket-Outlets and Similar Accessories ,

(i) All Sockets Polarities’ are Correct ,
(ii) That the Polarity of the Incoming Supply is Correct / Before the Supply is Energised ,
Your Checking to Ensure the Supply Authorities Polarity is Correct ,

Acceptable to Place a Temporary Bridge Between Phase & Earth in the Consumers Unit ,

(i) Test between Switched Live & Earth at the Ceiling Rose to Confirm Polarity
(ii) Operate Switch to Confirm Polarity
(iii) HSE Guidance Note GS-38 ↔ Electrical Equipment
→ You Should always Prove Isolation ← (iv) Use a Proving Unit
Then Test for Circuit is Dead , then Prove GS-38 it still Works
(v) Once the Supply is Energised Correct Polarity of the Incoming Supply may be Established Using An Approved
Approved Voltage Tester at the Mains , ( after Proving that GS-38 Voltage Indicator is Working )

(vi) Remember to Remove your Temp link , Phase & Earth

Once the Inspection & Testing has been Completed it is then of Vital Importance that the Relevant Documentation is Completed
Three Signatures’ are Required on the Electrical Installation Certificate , ( Three Signatures are still Required )

(i) Designer (ii) Installer (iii) Tester

Appendix 6 , (ix) When making Out and Signing a Form on behalf of a Company or Other Business Entity ,
Individuals should State ( for Whom they are Acting ) 632.3

Electrical Installation Certificate ,
To be Used When One Person is Responsible for the Design , Construction , Inspection & Testing of an Installation

Electrical Installation Certificate
This Certificate is Intended to be Issued Only for a New Electrical Installation or for New Work Associated with an
Addition or Alteration to an Existing Installation ,
It should Not have been Issued for the Inspection of an Existing Electrical Installation , A “ Periodic Inspection Report “
Should be Issue for such an Inspection ,

There are Three Main Reasons why we Certificate an Installation ,
(i) Addition to an Installation (ii ) an Alteration to an Installation (iii) New Installation

Which Certificate is Issued the Original should be Given to the Person Ordering the Work and a Duplicate by the Contractor , 632.1

Particular Care should be Given when Completing the Extent and Limitations Details of Periodic and Close Liaison ,
With the Client , is Essential at this Time , This is to Ensure that the Client is Fully Informed of what will and what Not be Tested ,
( All must be Negotiated with the Client )

631.2 Upon Completion of the Periodic Inspection & Testing of an Existing Instillation ,
Periodic Inspection Report , Shall be Provided , such Documentation shall Include Details of the Extent of the Installation & Limitations
Of the Inspection & Testing Covered by the Report , Together with a Record of the Inspection and the Results of Testing ,

621.4
The Extent and Results of the Periodic Inspection & Testing of an Installation , or any Part of an Installation , shall be Recorded ,

Person Ordering the Work : Periodic (i) First Periodic Test – Designer / Installer
(ii) Further Periodic Test – Tester / Inspector
(iii) Extent & Limitations Agreed with / Person Ordering The Work ,

Periodic Inspection Report
Notes , (5 ) p-339
The Extent and Limitations “ Box should fully Identify the Elements of the Installation that are Covered by the Report and
Those that are Not this Aspect having been Agreed with the Client and Other Interested Parties before the
The Inspection & Testing is Carried Out ,

The “ Extent and Limitations “ Box should fully Identify the Extent of the Installation Covered by this Report and any Limitations on the Inspection & Tests the Contractor should have Agreed these Aspects with you and any Other
Interested Parties ( Licensing Authority , Insurance Company , Building Society etc , before the Inspection was Carried Out

4118.3
Where a Circuit-breaker is Used the Maximum Value of Earth Fault Loop Impedance ( Zs ) shall be Determined by the
Formula in Regulation 411.4.5 Alternatively , the Values Specified in Table 41.4 may be Used instead of Calculations
For the Nominal Voltages ( Uo ) and the Types and Ratings of Overcurrent Device listed therein ,

What is the Maximum Earth Fault Loop Impedance Allowed when Using a 32A Type C
Circuit Breaker Giving s Disconnection time of 5sec , the Nominal Voltage to Earth ( Uo ) is 55v ↔ 41.6 ( 0.17Ω )



PS is this Helping anybody Please let me Know ,
When I don’t hear anything My Computer does Hand Stands , Amberleaf
Keep at it Chaps there’s always tomorrow ,

The On Site Guide & Guidance Note 3

Contain Detailed Information on how to Carry Out a Series of Electrical Tests on an Installation ,
612.2.1 Continuity of Protective Conductors ( Dead Test ) GN- 3
612.2.2 Continuity of Ring Final Circuit Conductors’ ( Dead Test ) GN- 3
612.3. Insulation Résistance ( Dead Test ) GN- 3
612.6 Polarity ( Dead Test ) GN- 3 By Continuity Methods
612.7 Earth Electrode Résistance ( Dead Test ) GN- 3 Battery ,

612.9 Earth Fault Loop Impedance ( Energized ) GN- 3
612.11 Prospective Fault Current ( Energized ) GN- 3
612.13. Functional Testing ( Energized ) GN- 3

In Addition to an Inspection these Test form the Basis of any Electrical Commissioning Process of an Electrical Installation ,

There are Two Main Types of Test / Commissioning Undertaken there are Initial Testing ,
And Periodic Testing , as the Name Suggests Initial Testing is Undertaken to Ensure the Installation is Safe and in Compliance with BS-7671 Prior to being Handed Over to the Client ,

Whilst a Periodic “ Report “ is Undertaken at Regular Intervals whilst the Installation is in Service to Ensure the Installation
Remains Safe and Fit for Use ,

The Sequence of Electrical Tests Undertaken Differs Slightly Between the Two ,

 

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RCD is Provided for Supplementary Protection Against Direct Contact its Operating Current must Not Exceed 30mA
( Must Operate in the Time Not Exceed 40mS at Residual Current of x5 its Rated Current )

Additional Protection RCD ( 612.10
The Verification of the Effectiveness of the Measures Applied for Additional Protection is Fulfilled by Visual Inspection & Test
Where RCDs are Required for Additional Protection the Effectiveness of Automatic Disconnection of Supple by RCDs shall
Be Verified Using Suitable Test Equipment According to BS-EN 61557-6 to Confirm that the Relevant Requirements’ are Met ,

612.1
The Tests of Regulations 612.2 / 612.13 Where Relevant , shall be Carried Out and the Results Compared with Relevant Criteria

30mA RCD

Test Button to Select 30mA

Half Current ( 15mA ) Test , 0º ≈ Positive Half Cycle ( RDC should Not Trip ) ½
Half Current ( 15mA ) Test , 180º Negative Half Cycle ( RDC should Not Trip )

Full Current ( 30mA ) Test , 0º ≈ Positive Half Cycle ( RDC should Trip ) x1 40mS
Full Current ( 30mA ) Test , 180º Negative Half Cycle ( RDC should Trip )

Five times Current ( 150mA ) Test , 0º ≈ Positive Half Cycle ( RDC should Trip ) x5
Five times Current ( 150mA ) Test , 180º Negative Half Cycle ( RDC should Trip )

100mA RCD 0º or ( Positive ) 180º ( Negative )

Test Button to Select 100mA

Half Current ( 50mA ) Test , 0º ≈ Positive Half Cycle ( RDC should Not Trip ) ½
Half Current ( 50mA ) Test , 180º Negative Half Cycle ( RDC should Not Trip )
Full Current ( 100mA ) Test , 0º ≈ Positive Half Cycle ( RDC should Trip ) x1
Full Current ( 100mA ) Test , 180º Negative Half Cycle ( RDC should Trip ) RCDs Remember L to E fault

Note that the Five Times Current Test is Not Required for a 100mA RCD

State Four Items of Electrical Equipment that would Require Functional Testing
( Functional Checks ) 612.13
(i) RCDs
(ii) Circuit Breakers
(iii) Isolators’
(iv) Cooker , Switches

Devices Used for Isolation , Switching for Mechanical Maintenance , Emergency Switching & Functional Switching , T/ 53-2 p-117
PS , Breakers can Now be Used as Primarily as Switches’ ,

Domestic Electricians read up on your ( TT Systems ) Uncle Sam is Watching

If Any Test Indicates a Failure to Comply , that Test and any Preceding Test , the Results of which may have been Influenced
By the Fault Indicated , shall be Repeated after the Fault has been Rectified ,

The Tests of Regulations 612.2 Continuity of Conductors to 612.6 where relevant , shall be Carried Out in the Order before the Installation is Energised , Where the Installation Incorporates an Earth-Electrode ,
the Test of Regulations 612.7 Shall also be Carried Out Before the Installation is Energised , GN-3 ( TT Systems ) or

Some Methods of Test are Describe in IEE Guidance Note 3 Inspection & Testing ,
Other Methods Are Not Precluded Provided they give Valid Results ↔ it is in the Regs , 2008 17th p-157

The Tests of Regulations 612.2 Continuity of Conductors to 612.6 where relevant , shall be Carried Out in the Order before the Installation is Energised , Where the Installation Incorporates an Earth-Electrode ,
the Test of Regulations 612.7 Shall also be Carried Out Before the Installation is Energised , GN-3 ( TT Systems ) or

Note that the Five Times Current Test is Not Required for a 100mA RCD

State the Action to be Taken Regarding the Earthing Conductor Before Measuring the Résistance of an Earth Electrode
GN-3 ( Earth Electrode Testing )
(i) DO NOT DISCONNECT any Protective Conductors BEFORE Isolating the Supply ←←← think about this One
(ii) Disconnect Earthing Conductor at ( MET ) ↔ Link in D/B , to Avoid Parallel Earth Paths

State Two Reasons why it is Necessary to Measure External Earth Fault Loop Impedance at the Origin of an Installation ,
GN-3 ( Determining Ze )
(i) To Verify an Earth Connection
(ii) The Value is Equal to or Less than the Value Determined by the Designer ,

State the Test Voltage and Minimum Acceptable Value of Insulation Résistance for the Following Circuits
(i) 400v 3 Phase Motor ( 500v dc 1.0MΩ )
(ii) 760v Discharge Lighting Circuit ( 1000v dc 1.0MΩ )
(iii) 45v FELV Circuit ( 250v dc 0.5MΩ

Identify one other Test that is Automatically Preformed when undertaking a Ring Circuit Test
GN-3 ( Continuity of the Ring Final Circuit ) 612.2.2
Polarity , 612.2

Identify the Test that should be Applied to Verify Polarity after the Supply is Energised ,
GN-3 ( Polarity )
Test to Verify Correct Polarity of the Incoming Live Supply , ( Test Made at the Origin Using Approved Voltage Indictor GS-38 )

State the Correct Sequence for Under taking an Insulation Résistance Test florescent Light
Circuit Containing two-way Switching
GN-3 ( Insulation Résistance Testing )
(1) Supply Must be Isolated ( Dead Test )
(2) All Lamps Removed
(3) Insulation Résistance Test between Line Conductors and Neutral
(4) Insulation Résistance Test between Line Conductors and CPC
(5) Two-Way Switches’ Operated During Test ,

State items of Equipment / Components that may Need to be Removed prior to Carrying out a Test for Insulation Résistance
On a Circuit 612.3
GN-3 ( Insulation Résistance )
Pilot or Indicator Lamps
Dimmer Switches
Touch switches

Under what Circumstances would it be Appropriate to Issue a Single Signature Electrical Installation Certificate
GN-3 ( Certificates )
Where Design , Construction Inspection and Testing is the Responsibility of One Person ( in the Regs ,

State the Necessary Action that should be taken by an Inspector on Discovering a Damage Socket-Outlet
With Exposed Live Parts During a Periodic Inspection & Test
GN-3 ( Required Competence )
Make an Immediate Recommendation to the Client to Isolate the Defective Part

State the Formula Used to Calculate Impedance ( Zs ) at the Furthest Point within a Circuit
GN-3 ( Earth Fault Loop Impedance ) 612.9
( Zs = Ze + R1 + R2 )
Where Ze is by Measurement or Enquiry
And ( R1 + R2 ) by Measurement ,

State the Maximum Recommended Value of Résistance for an Earth Electrode p-50 Note 2
GN-3 ( Earth Electrode for RCDs )
(i) Electrodes having Resistances’ in the Excess of 200Ω will Require Further Instigation , ↔ “ Houston we have a problem “
(ii) Note , Electrodes Resistances Obtained in Excess of 200Ω May Indicate Unstable Soil Conditions

Formula for Estimating Energy Consumption
You can Use this Formula to Estimate an Appliances Energy Use ,

( Wattage x Hours Used per Day ÷ 1000 = Daily Kilowatt-Hour ( kWh ) Consumption .
( 1 kilowatt ( kW ) = 1,000 Watts )

Multiply this by the Number of Days you Use the Appliance During the Year for the Annual Consumption ,
You can then Calculate the Annual Cost to Run an Appliance by Multiplying the ( kWh ) per Year by your
Local Utility’s Rate per Year by your Utility’s Rate per ( kWh ) Consumed ,

Note : To Estimate the Number of Hours that a Refrigerator Actually Operates at its Maximum Wattage ,
Divide the Total Time the Refrigerators’ is Plugged in by Three Refrigerators’, Although “on” all the Time ,
Actually Cycle On and Off as Needed to Maintain Interior Temperatures ,

Window Fan ,
( 200 Watts x 4 Hours / Day x 120 Days / Year ) ÷ 1000
= 96 ( kWh ) x 8.5 % / ( kWh ) £ 8.16 Year - ( 200 x 4 x 120 Div 1000 ( 96 x 8.5 = 8.16 )

Computer / Monitor
( 120 + 150 Watts x 4 Hours / Day x 365 / Year ÷ 1000
= 394 ( kWh ) x 8.5 % / ( kWh )
= £ 33.51 / Year


Standard Light Bulb 4 Hour a Day 100 Watt £ 14.60 per Year
Low Energy Light Bulb 4 Hour a Day 18 Watt £ 2.63

Aquarium = 50 – 1210 Watts
Clock Radio 10
Personal Computers ( CUP / Awake / Asleep = 120 / 30 or Less
Monitor – Awake / Asleep = 150 / 30 or Less
Laptop – 50
Refrigerator ( Frost Free , 16 cubic feet ) = 725

Cost per year
This I hope this will Help you Lionel ,

 

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17th BS-7671 : 2008 ♫ ♫ ♫ Old to New
GN3
The Requirement for 40mS at a Residual Current of x5 Operating Current comes from Regulation 415.1.1 when the RCD is used

The Use of RCDs with a Rated Residual Operating Current , Not Exceeding 30mA and Operating Time Not Exceeding 40mS
Residual Current x5 is Recognised In a.c Systems as Additional Protection ,
( Provision for Basic Protection / Provision for Fault Protection ) Right One ,

Protection Against Electric Shock ( Chapter 41 p-44 17th

16th BS-7671 2001: ←←←
They are Still a lot of Old Notes and Stuff from the Internet ,

( i) Protection in Use Without A Fault ( Now Designated Basic Protection Was Referred to as Protection Against ( Direct Contact
(ii) Protection Under Fault Conditions ( Now Designated Fault Protection Was Referred to as Protection Against ( Indirect Contact

PS , Supplementary Protective Bonding Conductors’ is Complementary Measure for “ Fault Protection “

Functional Testing 612.13 / RCD Testing Detail a “ Quarterly Test “ , Regulation 514.12.2 Domestic Electricians

MCB's to BS EN 60898 RCBOs to 61009-1 for disconnection times of 0.4 & 5 sec

411.3.2.2 the Maximum Disconnection time Sated Table 41.1
( Shall be Applied to FINAL RING CIRUITS NOT EXCEEDING 32Amps TN-systems 0.4 sec ONLY )

411.3.2.3
In A TN-System , a Disconnection time ( 5sec Final Ring Circuits EXCEEDING 32Amps ONLY )

The Maximum Disconnection Time TN-Systems ( 230v to Earth 0.2 sec Only )

Remember to Keep You ( Earth Impedance Ω Zs Very Very Low )

Protection Against Electric Shock ,
( That Live Parts , Such as Energized Conductors , Must Not be Accessible )
( The Conductive Parts which are Accessible , Such as Metal Enclosures of Equipment or Metal Pipes , Must Not be Live )
Must be Achieved both in Normal Conditions ( No Faults on Electrical Systems )

(i) By Touching Live Parts at Different Potential , Max , Touch Voltage of 50 Volts
(ii) A Live Part and Earth Potential ,

● Standards Documents , BS / British Standards ( EN / European Standards ( ISO / Worldwide British Standards ,

For the Apprentice ,

( Moulded-Plug ) a Non-wiriable Plug , the Manufacture of Which is Completed by Insulating Material Moulded Pre-Assembled
Component Parts and the Terminations of Flexible Cord ,
( Fuse Plug ) a Plug having Provision for a Replaceable Cartridge Fuse Link ,

Terminal , a Means by which the User can Make an Electrical Connection between the Appropriate Flexible Cord and the
Conducting Parts of the Plug Without the Use of Special Purpose Tools ,

( Screw-Type-Terminal )
A Terminal in Which the Connection is Made Direly by Means of Screws or Nuts of any Kind or Indirectly through an
Intermediate Metal Part such as a Washer , Clamping Plate or Anti-Spread Device on Which the Screw Bears Directly ,

Example of Screw-Type Terminals ,
A Pillar Terminal is a Terminal in which the Conductor is Inserted into a Hole or Cavity ,
Where it is Clamped Under the Shank of the Screw or Screws ,

A Screw Terminal is a Terminal in Which the Conductor is Clamped Under the Head of the Screw ,

A Screw Terminal is a Terminal in Which the Conductor is Clamped Under a Nut ,

( Clamp-Type ) Screwless Terminal ,
A Terminal in Which the Connection is Made by Clamping the Conductor of Flexible Cord between two Metallic Surfaces
Without the Use of a Screw ,

( Fuse Carrier ) A Movable or Removable Part Designed to Carry , Retain , Cover and / or Remove the Fuse Link ,

Classification ,
(i) Rewirable or Non- Rewirable
(ii) For Normal Use or Rough Use ,
(iii) Fitted with Screw or Clamp Type ( Screwless ) Terminals ,

(i) for Screw Type Terminals the Clamping Screw Shall be Tightened with Torque to Two-Thirds of the Appropriate Value ,
(ii) for Clamp-Type ( Screwless ) Terminals the Connection shall be Made in Accordance with the Manufacturers Instructions ,

The Résistance between the Earthing Terminal or Termination and any Other Nominated Metal Part shall Not Exceed 0.05Ω

“ Fundamental Principles “

Protection for Safety 131.

Fundamental Reason for Inspecting & Testing an Electrical Installation is to Determine Whether a New Installation is Safe To be Put into Service ,

Following Statements
(i) Installations Must be Inspected and Tested on Completion and also During Erection
(ii) The Purpose of the Inspection is to Verify Equipment is Correctly Selected and Erected in Accordance with BS-7671
(iii) Precautions shall be Taken to Avoid Damage to Property During Inspection & Testing 131.1

131.1
The Requirements of this Chapter are Intend to Provide for the Safety of Persons , and Property against Dangers & Damage
Which May arise in the Reasonable Use of Electrical Installations ,

Or Whether an Exciting Installation is Safe to Remain in Service Until the Next Inspection is Due ,
● If it is Verified that New Installation , Work fully Complies with the Current Requirements’ BS-7671 Standards ,
● All Equipment Must be Suitable for its Intended Use ,

Initial Verification Chapter 63 ( Inspection & Testing ) Construction Inspection and Testing of the Installation shall ,
Which takes Account of their Respective Responsibilities for the Safety of that Installation , 632.3 / 632.1

Visual Inspection is Necessary Before Testing to Check Whether ( There is Adequate Access to Switchgear ,

Any Faults or Defects Indentified During an Initial Verification should be ( Made Good before Issuing the Certificate ,

632.4
Defects or Omissions Revealed During Inspecting & Testing of the Installation Work

During Inspection of a Distribution Board Containing Exposed Conducive Parts it Should be Verified that ,
( The Door can Only be Opened with a Key or Tool , 416.2.4. (i) )

Before Commencing an Initial Inspection and Test , the Inspector should have Copy of the ( Inspection Specification ,
the Following should Accompany the Inspection and Test Certificate ( Copies of the Inspection & Test Schedules ,

Initial Verification
Is Intended to Ensure that the Electrical Installation is Safe to but into Service , and that it is Likely to Remain in Such a Condition at Least Until the First Periodic Inspection ,

Something to Read ,

Electrical Contractors that Issue Inaccurate or Misleading Certificates or Reports
Are Liable to Criminal Prosecution by Trading Standards Officers
Under the Trade Descriptions Act 1968 or Other Relevant Legislation ,

The Term “ Inspector “ is Used to Describe a Person Responsible for Inspecting & Testing an Electrical Installation ,
All Persons Carrying Out the Inspecting & Testing of Electrical Installations Must be Competent to do So ,
This May come up in the Future ,

Safe Working Procedure ( Regulation 12 )
Means for Cutting of the Supply and for Isolation

611.1
Inspection shall Proceed Testing and Shall Normally be Done with that Part of the Installation under Inspection Disconnection from the Supply ,

Precautions for Work on Equipment Made Dead ( Regulation 13 )
Adequate Precautions shall be Taking to Prevent Electrical Equipment Which has been Made Dead
In Order to Prevent Danger while Work is Carried Out on or Near that Equipment becoming Live ,
( Electrician Must Carry Out Safe Isolation Procedure )

Open the Means of Isolation for the Circuit(s) to be Inspected

416.2.4
Where it is Necessary to Remove a Barrier or Open an Enclosure or Remove Parts of Enclosures
What you are Verifying at the Same Time ,
( Top of CU , IP4X 416.2.2 ( the Sides of the CU must Conform to IP2X 416.2.4 (ii)
( IP Rating for RCCBs / RCBOs / RCDs ( Front Plate is IP4X / Screw IP2X ( BS Finger Test )

Compliant with GS-38 with Regards to Test Leads
Prove the Correct Operation on a Suitable Voltage Test Instrument Against a Known Source

Test , with the GS-38 Voltage Test Instrument All Conductors of the circuit(s) you are Working on to Confirm that there’s No
Live Supply to the Equipment your Working On ,

Prove the Voltage Test Instrument Against the Know Source to Check that it was Functioning Correctly

Remember GN-38 Electrical Test Equipment / Test Equipment for Circuits with Rated Voltages Not Exceeding 650 Voltages

BS-EN 61010 GN-38
Equipment Included in Scope ,
This Part of IEC 61010 Specifies General Safety Requirements’ for Electrical Equipment Intended for Professional , Industrial Process ,
BS-EN 61557
Electrical Safety in Low-Voltage Distribution Systems up to 1000V a.c / 1500V d.c Equipment for Testing Measuring ,

Proving Unit for on Site-Testing and Verification of Electrical Test Equipment
Proving Unit Produces 690v AC / DC to Enable Voltage Indicators to be Checked
Unit is Suitable for Indicators with 230v / 415v ,

 

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Electrical Installation Certificate is to be Used Only for the Initial Certification of a New Installation , or of New Work
Associated with an Alteration or Addition to an Existing Installation , Carried out in Accordance with BS-7671

Electrical Installation Certificate
( Requirements for Electrical Installations BS-7671 IEE Wiring Regulations

Nature of Installation Work
● Three Boxes are Provided to Enable the Contractor to Identify the Nature of the Installation Work ( p-332 ) ,

● New / This box should be Ticked Only if the whole Installation has been Installed as New , or if a Complete Rewire is Carried Out ,

● An Addition ( to an Existing Installation ) this box should be Ticked if an Existing Installation has been Modified by the Addition of One or More New Circuits’ ,

● An Alteration ( to an Existing Installation ) this box should be Ticked where One or More Existing Circuits have been Modified or Extended , or Items such as Distribution Boards and Switchgear have been Replaced ,

Where Appropriate , both the “ Addition “ and the “ Alteration ” Boxes may be Ticked ,

There are Three Main Reasons why we Certificate an Installation ,
(i) Addition to an Installation (ii ) an Alteration to an Installation (iii) New Installation ,

Visual Inspection of a New Installation must be Carried out ,
During Erection and Before Testing ,

Requirement of the Inspection Checklist ,
Prescience of a BS Mark or Other Suitable Certification ,
Correct Selection of Cable and Protection Devices ,
No Visible Damage ,

Inspection Domestic Consumer Unit would Need Verification for ,
Identification of Conductors’ ,
Rating and Type of Protective Devices
Correct Connection of Single-Pole Devices

Domestic Electrical Installation Certificate Three pages , 3x1

Signatories
Two Options are Available for Certification of the Installation ( Domestic Electrician )
(i) Where the Design , the Construction and Inspection & Testing are the Responsibility of One Person ,

“ Electrical Installation Certificate “ Signatories

(ii) Collectively Certified in the Section Headed , p- 332 / p-333 ( When Three People are Needed )
(1) ( For Design ) (2) ( For Construction ) (3) ( For Inspection & Testing )
Alternatively , where Approved Contractor Issuing the Certificate has Not been Responsible for the Design
And / or the Inspection & Testing of the Electrical Work , Certification of the Three Signatories must be Carried Out
Separately using the Three “ Particulars of Signatories to the Electrical Installation Certificate Design “ Construction ” Inspection & Testing “ Respectively ,

17th New Regulations that all Socket-Outlets up to 20A , Used by Ordinary Persons need to be RCD Protected by a Device if
With a Maximum Tripping Current of 30mA ( 411.3.3 (i) , Additional Protection

Knowing the Earth Loop Impedance , it is Possible to Calculate the Value of the Prospective Fault Current ( PFC )
At any Point in an Installation to Ensure that all Installed Protective Devices are of Adequate Rating to Clear the Potential Fault
Current Level ,
The Earth Loop Impedance Test Measures the Résistance of the Path that a Fault Current would take between Line / Protective Earth
this Must be Low Enough to Allow Sufficient to Flow to Trip a Circuit Protection Device ,

100mA / 300mA RCDs are Really Protection Against Fire rather than Shock ,

Residual Current Device shall have a Rated Residual Operating Current ( I∆n ) not Exceeding 30mA and an Operating Time Not
Exceeding 40mS at Residual Current of 5 ( I∆n )

As Provided by BS-4293 ,
BS-7071: 1992 ( Specification for Portable Residual Current Device , Safety Plug 13A- Tripping Current 30mA / 10mA Tripping Time ( 30mS ) IP 44

Old ↔ RCD BS-7288 Protected Switched Socket-Outlet ( SRCDs : 1992 ) Red / Black
SRCDs Specification , Rated Current 13A , Rated Trip Current 30mA , Trip Time 30mS

New ↔ BS-7288
Power Breaker 2G RCD , Metal-Clad , Trips 40mS at 30mA Double-Pole ( BS-7288 , BS-1363 , BS-4293 , Passive Operation
Cross-References BS-1362 ( Domestic , Cartridge Fuses , p-229 ( BS-1363 Class I Equipment / 3 / 5 / 13Amp , p-229

1G DP RCD , ( Metal Clad )
For Use in Industrial and Domestic , 13A max Load Trips at 30mA - BS-7288 / 200mS

Tested According to Specification BS-7071:1992 and BS-1363 British Standards Institution

BS-EN 61008-1
BS-EN 61008-1 : 2004
If this comes up ( Old BS-4293 Withdrawn ) ↔ Now RCCBs , Residual Current Operated Circuit-Breaker , Remains Current , ( 41.5

BS-EN 61009-1
BS-EN 61009-1 : 2004
If this comes up ( Old BS-4293 Withdrawn ) ↔ Now RCBOs , Residual Current Operated Circuit-Breaker , Remains Current , ( 41.3
If this comes up ( Old BS-3871 Withdrawn ) ↔ Now BS-EN 60898 MCBs , 2003 Remains Current , ( 41.3
If this comes up ( Old BS-4293 ( Replaced by BS-EN 61008-1 , look in the Regs ,

For The Apprentices ,
Am trying to make it Easy for you to Understand , Amberleaf ,

Domestic Electrical Installation Certificate
Is Not Intended to be Issued to Confirm the Completion of the Contract ,

This Certificate is a Declaration of Electrical Safety which should be Issued before an Installation is Put into Service ,
Domestic Electrical Installation Certificate
Is to be Used Only for the Initial Certification of a New Installation ,
New Work Associated with an Alteration or Addition to an Existing Installation , Carried Out in Accordance with BS-7671

Certificate May Only be Used where Every One of the Following Conditions Apply ,

The Electrical Installation Work Relates to a Single Dwelling ( House or Individual Flat )

The Design , Construction , and the Inspection & Testing of the Electrical Installation work has been the Responsibility of One Person
Or Organization ,

The Installation Forms Part of a ( TT ) ( TN-S ) ( TN-C-S / PME - Systems ,
Each of which falls within the Scope of the Domestic Electrical Installation Certificate

The Protective Measure for Fault Protection is Provided Primarily by Automatic Disconnection of Supply ( ADS ) 415.1.1
Earthing & Protective Bonding Arrangements if Necessary for the Protective Measure Applied for Safety ,
131.8 Alteration or Additions to an Installation ,

Installation Work Falling within the Scope of the Domestic Electrical Installation Certificate ,
Contractor will Invariably have Assumed the Role of the Designer ,

This Certificate is a Declaration of Electrical Safety which should be Issued before an Installation is Put into Service ,
Domestic Electrical Installation Certificate
Is to be Used Only for the Initial Certification of a New Installation ,
New Work Associated with an Alteration or Addition to an Existing Installation , Carried Out in Accordance with BS-7671

RCD Test Instrument , Operating Time in Milliseconds when Subjected to a Test Current Equal to the Operating Current I∆n

Insulation Résistance Enter the Measured Values of Line / Line ( Only Applicable for Multi-Phase Circuit(s)

Insulation Résistance Line / Neutral Line / Earth Neutral / Earth

“ Inspection of New Installation Work “
BS-7671 Requires that Every Installation , and Every Alteration or Addition to an Installation ,
Is Inspected During Erection and on Completion Before being put into Service to Verify so far as is Reasonable Practicable ,

Initial Verification
It is a Requirement of BS-7671 that the Relevant Design Information is Made Available to those Carrying Out the Inspection & Testing of New Installation Work ,
Irrespective of whether the Design was Carried Out by the Contractor or by Another Party ,
610.2
The Results of the Assessment of the Fundamental Principles Section 131 , the General Characteristics Required by
Section 311 / 313 , together with the Information Required by Regulation 514.9.1 shall be Made Available to the Person(s)
Carrying Out the Inspection & Testing ,

Inspection
Verify , Comply with Appropriate British / European or Equivalent Product Standards , 133.1.1 / 133.1.2
Been Correctly Selected and Erected , Not Visibly Damaged , Defective or Deteriorated such that Safety is Impaired
Suitable for the Environment in which they are Installed

Chapter 41 Protection Against Electric Shock
Basic Protection – Means of Protection Against Electric Shock Under Fault-Free Conditions ,
Fault Protection – Means of Protection Against Electric Shock Under Single Fault Conditions ,

“ Protective Measure “ BS-7671 Must Consist of
(i) An Appropriate Combination of a Provision for Basic Protection and an Independent Provision for Fault Protection ,
(ii) An Enhanced Protective Provision which Provides both Basic and Fault Protection

 

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For the Apprentice ( this is all you need on BS-EN 61009-1 to help you understand something’s )
RCBOs BS-EN 61009-1 ( 41.3 )

● RCBOs ( Combined MCB / RCD ) Breaking Capacity ( kA ) BS-EN 61009-1 41.3
MCBs ( Breaking Capacity ( kA BS-EN 60898-1 ) 41.3

Devices are Intended to Protect People Against Indirect Contact ( Carelessness by Users )
Exposed Conductive Parts of the Installation being Connected to an Appropriate Earth Electrode and to Protect against Overcurrents
The Wiring Installations of Buildings and Similar Applications’ ,
May be Used to Provide Protection Against Fire-Hazards due to a Persistent Earth Fault Current ,

RCBOs
Having a Rated Residual Operating Current Not Exceeding ( 30mA ) 415.1.1
Also Used as a Means for Additional Protection in the Case of Failure of the Protective Means against Electric Shock ,

RCBO
6A / 30mA - 6kA type B
10A / 30mA - 6kA type B
16A / 30mA - 6kA type B
20A / 30mA - 6kA type B
25A / 30mA - 6kA type B
25A / 30mA - 6kA type B
32A / 30mA - 6kA type B
40A / 30mA - 6kA type B

RCBO
There are Important Differences when Using the Single-Pole RCBO most Commonly Used in the UK
( as Opposed to Two-Pole RCBOs Used in Europe )

With Single-Pole RCBOs Even when they have Tripped , the Neutral Wire is Not Interrupted so Operators may still Risk
Getting an Electric Shock ,

Two-Pole RCBOs Provide a Much Safer Solution as they Interrupt Both the Live & Neutral Wires ,

Primarily , the RCBO , a Residual Current Breaker with Overcurrent Protection , will Both Act as a Circuit-Breaker
And will Prevent Damage if there is an Overload Situation ,

For any Business or Operation , Safety is a Top Priority , a Two-Pole RCBO is the Circuit Breaker of Choice ,

Trip Current Settings , 30mA 100mA 300mA 500mA

Test Current Results
t∆ ½ I∆n RCBO Must Not Trip 0.5 / ½
t∆ x1 I∆n RCBO Must Trip Within 300mS ( BS-EN Only ←
t∆ x2 I∆n RCBO Must Trip Within 200mS ( BS- Only ←
t∆ x5 I∆n RCBO Must Trip Within 40mS 415.1.1

Harmonised Standards BS-EN 61008-1 / BS-EN 61009-1 ←
All the Device to Operate within 300mS at 100% I∆n

Previous Standards BS- 4293 has a Limit of 200mS ( When Testing )
x5 I∆n Remain Unchanged and are 40mS for all Standards ←

Regulations Appendix 3 table 3A RCD table p-243

 

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BS- Rating Protection from Solids Protection from Liquids

IP00 No Protection No Protection
IP01 No Protection Condensation
IP02 No Protection Water Spry < 15 degrees from Vertical
IP03 No Protection Water Spry < 60 degrees from Vertical
IP04 No Protection Water Spry from any Direction
IP05 No Protection Low Pressure Water jets from any Direction
IP06 No Protection High Pressure Water jets from any Direction
IP07 No Protection Immersion Between 15cm and 1m Depth
IP08 No Protection Long term Immersion to a Specified Pressure
IP10 Touch by Hands ( > 50mm ) No Protection
IP11 Touch by Hands ( > 50mm ) Condensation
IP12 Touch by Hands ( > 50mm ) Water spray < 15 degrees from Vertical
IP13 Touch by Hands ( > 50mm ) Water spray < 60 degrees from Vertical
IP14 Touch by Hands ( > 50mm ) Water spray from any Direction
IP15 Touch by Hands ( > 50mm ) Low Pressure Water jets from any Direction
IP16 Touch by Hands ( > 50mm ) High Pressure Water jets from any Direction
IP17 Touch by Hands ( > 50mm ) Immersion Between 15cm and 1m Depth
IP18 Touch by Hands ( > 50mm ) Long term Immersion to a Specified Pressure
IP20 Touch by Fingers ( > 12mm ) No Protection
IP21 Touch by Fingers ( > 12mm ) Condensation
IP22 Touch by Fingers ( > 12mm ) Water spray < 15 degrees from Vertical
IP23 Touch by Fingers ( > 12mm ) Water spray < 60 degrees from Vertical
IP24 Touch by Fingers ( > 12mm ) Water spray from any Direction
IP25 Touch by Fingers ( > 12mm ) Low Pressure Water jets from any Direction
IP26 Touch by Fingers ( > 12mm ) High Pressure Water jets from any Direction
IP27 Touch by Fingers ( > 12mm ) Immersion Between 15cm and 1m Depth
IP28 Touch by Fingers ( > 12mm ) Long term Immersion to a Specified Pressure

Rating Protection from Solids Protection from Liquids

IP30 Tools & Wires ( > 2.5mm No Protection
IP31 Tools & Wires ( > 2.5mm Condensation
IP32 Tools & Wires ( > 2.5mm Water Spray < 15 Degrees from Vertical
IP33 Tools & Wires ( > 2.5mm Water Spray < 60 Degrees from Vertical
IP34 Tools & Wires ( > 2.5mm Water Spray from any Direction
IP35 Tools & Wires ( > 2.5mm Low Pressure Water Jets from any Direction
IP36 Tools & Wires ( > 2.5mm High Pressure Water Jets from any Direction
IP37 Tools & Wires ( > 2.5mm Immersion between 15cm and 1m Depth
IP38 Tools & Wires ( > 2.5mm Long term Immersion to a Specified Pressure
IP40 Tools & small wires ( > 1mm ) No Protection
IP41 Tools & small wires ( > 1mm ) Condensation
IP42 Tools & small wires ( > 1mm ) Water spray < 15 degree from Vertical
IP43 Tools & small wires ( > 1mm ) Water spray < 60 degree from Vertical
IP44 Tools & small wires ( > 1mm ) Water spray from any direction
IP45 Tools & small wires ( > 1mm ) Low Pressure water jets from any Direction
IP46 Tools & small wires ( > 1mm ) High Pressure water jets from any Direction
IP47 Tools & small wires ( > 1mm ) Immersion between 15cm and 1m depth
IP48 Tools & small wires ( > 1mm ) Long term Immersion to a Specified Pressure

Rating Protection from Solids Protection from Liquids

IP50 Limited dust Ingress Protection No Protection
IP51 Limited dust Ingress Protection Condensation
IP52 Limited dust Ingress Protection Water spray < 15 degree from Vertical
IP53 Limited dust Ingress Protection Water spray < 60 degree from Vertical
IP54 Limited dust Ingress Protection Water spray from any Direction
IP55 Limited dust Ingress Protection Low Pressure Water jets from any Direction
IP56 Limited dust Ingress Protection High Pressure Water jets from any Direction
IP57 Limited dust Ingress Protection Immersion between 15cm and 1m depth
IP58 Limited dust Ingress Protection Long term Immersion to a Specified Pressure
IP60 Total dust Ingress Protection No Protection
IP61 Total dust Ingress Protection Condensation
IP62 Total dust Ingress Protection Water Spray < 15 degrees from Vertical
IP63 Total dust Ingress Protection Water Spray < 60 degrees from Vertical
IP64 Total dust Ingress Protection Water Spray from any Direction
IP65 Total dust Ingress Protection Low Pressure Water jets from any Direction
IP66 Total dust Ingress Protection High Pressure Water jets from any Direction
IP67 Total dust Ingress Protection Immersion between 15cm and 1m Depth
IP68 Total dust Ingress Protection Long term Immersion to a Specified Pressure
IP69k Total dust Ingress Protection Steam jet Cleaning

2.1 Learning Outcome ( 2392-10 ) Appendix 2 p-240 / 341

Demonstrate an Understanding of the Construction , Design & Management Regulations 2007 ,

Statutory Instruments
2007 No 320 ,
Heath & Safety

The Construction ( Design & Management ) Regulations 2007
Made 7th February 2007
Laid before Parliament 15th February 2007
Coming into Force 6th April 2007

The Construction , Design & Management Regulations are Statutory ( LAW ) and Came into Force in their Present form on 6th April 2007

The Regulations Place a Duty on Virtually Everyone Involved in Construction work ,
Duty Holders have a Legal Duty to Ensure Heath & Safety Measures are Implemented and Adhered to ,
Workers on the Site Also have a Duty to Adhere to Heath & Safety Requirements , A Worker is Anyone Who Carries Out Construction Work ,
Alterations , Maintenance or Demolition , in Order to be Aware of Heath & Safety Requirements Workers must have a
Heath & Safety Certificate such as the CSCS Card ,

The Construction , Design & Management Regulations Requires a Heath & Safety File to be Prepared for a Particular Site ,
This is Produced by the Planning Supervisor and would Include :

(i) a Description of the Project ,
(ii) a General Statement of Heath & Safety Principles and Objectives for the Project ,
(iii) Information about Restrictions Which may Affect the Work such as , Neighbouring Buildings ,
Utility Services , Vehicle Traffic , Pedestrian Traffic & Work Activities of the Client ,

The Heath & Safety File Should be Available for Anybody to Access ,

Heath & Safety Executive ( HSE )

In Order to Ensure Heath & Safety is being Properly Implemented to Protect People Against Risk to Heath & Safety
At Work a Government Body Known as the ( HSE ) Police the Construction Industry ,

 

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Unit 2 ( Revision Points ) 2392-10
(1) the Electricity at Work Regulations 1989 ( EAWR ) are up to Date and Compulsory ,
(2) Before becoming Involved with a Dangerous Work Activity the Electricity at Work Regulations 1989
Requires a Person to have Sufficient Knowledge and Experience ,
(3) the Electricity at Work Regulations 1989 is Under the General 2 Umbrella 2 of the Heath & Safety at Work Act 1974 ,
(4) a Breach of Any Law, and in this Instance Electricity at Work Regulations 1989 can Result in a Fine and/or a Prison Sentence ,
(5) the Safe Use of Electricity in the Workplace is Everybody’s Responsibility ,
(6) BS-7671 :2008 Requirements for Electrical Installations ( 17th Edition ) are Non Statutory i.e. ( Not Law ) ↔ 114.1 ←
They are , However , A British Standard Code of Practise and May be Used as Evidence in Court of Law
In Order to Prove that Legal Requirements such as the Electricity at Work Regulations 1989 ( have been Met )
(7) the 17th Edition Wiring Regulations are Not Always a Practical Means to Ensure Electrical Work on Site is to the
Required Standard , a More Practical Approach may be to Use the IEE On Site Guide for Installations up to and Including
100 Amps e.g. Domestic ,
(8) Inspection & Testing Electrical Installations , to BS-7671 : 2008 helps to Insure that the Installation is Safe , Functioning and
Complies with the Legal Requirements ,
(9) the IEE Produce BS-7671 : 2008 and are Recognised by the Heath & Safety At Work Act 1974 , and -
the Electricity at Work Regulations 1989 Other Regulations such as the Control of Substances Hazard to Heath ( COSHH ) -
Regulations 2002 Do Not Recognise the IEE since it is Not Relevant to that Particular Area of Safety ,
(10) although BS-7671 : 2008 ( 17th Edition ) covers Installations such as a Room Containing a Bath or Shower , Swimming Pools and Fairgrounds it Does Not Cover Installations Such as Ships , Aeroplanes , Motor Vehicles and / Off-Shore Installations

(11) Regulations come into Force after they have been Laid before Parliament , for Example ,
The Construction , Design & Management Regulations were Laid before Parliament on the 15th February 2007
And came into Fore on the 6th April 2007 ,

(12) the Construction , Construction , Design & Management Regulations 2007 are Designed to Identify Hazards so that they
Can Ideally be Removed or at Least Minimised ,

(13) the Contractor , According to the Construction , Design & Management Regulations is a Business Involved in Construction ,
Alteration , Maintenance or Demolition ,

(14) the Contractor or Worker , According to the Construction , Design & Management Regulations 2007
Is Regarded as the Duty Holder ,

(15) the Heath & Safety File is a Requirement of the Construction , Design & Management Regulations 2007
Its Purpose is to Assist Anybody who Carries Out Work to Do so in a Safe Manner ,

(16) the Heath & Safety Executive ( HSE ) Guidance Booklet , Electrical Safety on Construction Sites ( HS(G) 141
Is Not Statutory ( LAW ) but a Guidance Note to Help to Ensure Electrical Safety on Construction Sites ,

(17) Risk Assessments are a Very Useful Tool in Dealing with Hazards , Once a Hazard has been Indentified it should
Ideally be Removed , if this is Not Possible or Practical it Should be Minimised ,

(18) it has been Found that the Most Common Risk of Electric Shock on Construction Sites is from the Use of Portable Electrical Equipment , it is therefore Important that this Equipment is Regularly Maintained ,

(19) the HSE Guidance Booklet , Electrical Safety on Construction Site HS(G) 141 Emphasises the Need for Risk Assessments to be Carried Out and to Carefully Plan any Operation Prior to Carrying it Out ,

(20) the Five Steps Involved with a Risk Assessment are to Look for Hazards , Decide who it Affects and how ,
Evaluate the Risk to see if More should be Done , Record your Findings and Review your Assessment ,



Unit 3.1 2392-10
State the Human Senses that may need to be Employed During the
Initial Verification of an Installation ,

During the Initial Inspection it is Important to Use the Following Senses ,

(1) Sight ,
A Visual Inspection Very Important since it can pick up a Large Number of Faults , ( Being )
(i) Labelling ,
(ii) Incorrect Cable or Cable Size ,
(iii) Damage Equipment
(iv) Incorrect Rotation of Motors or Equipment ,
(v) Lights Not Functioning ,
(vi) Incorrect Protective Devices Rating ,

(2) Touch ,
Touching Parts may Show Faults such as ,
(i) Overheating ,
(ii) Loose Connections ,
(iii) Poor Fixings of such things as Accessories
(iv) Unexpected Vibration of Accessories or Equipment

(3) Smell ,
The Sense of Smell may Indicate ,
(i) Equipment Overheating
(ii) Cables Overheating Due to Overload ,
(iii) Loose Connections Causing Terminals to Overheat ,

(4) Hearing ,
Sound may Indicate Problems such as ,
(i) Unnecessary Arcing Due to Loose Connections ,
(ii) Vibration of Transformer Cores ,
(iii) Poor Contactor Operation Due to Dirt on Pole Faces ,

Why do we Inspect & Test Installation ,
Precise and Detailed Examination is Essential to Show a Customer that no Hazardous or Dangerous Condition Exists
Which could lead to Damage , Injury or Death ,

● It Provides an “ official “ Record of the Condition of an Installation on the Day it was Tested ,

See Signs of Arcing in Backbox and Evidence of Arcing on Conductor

BS-7671:2008
● Guidelines are Detailed in BS-7671:2008 part- 6 Chapter 61 ( p-156 )
● These Regulations Detail Both Visual & Instrumental Inspections & Tests for a New Installation ,
● Periodic Inspections & Minor Work Certification is Carried Out on Existing Installation
( Chapter 62 & 63 – see ( 131.8 Additions & Alterations’ to an Installation )

What Problems can be Encountered During Inspection & Testing
Loose / Missing / Snapped Conductors ,
Conductors Trapped by Securing by Screws
Screws through Concealed Cables
Incorrect Wiring
Incorrect Colour Identification
CPC Conductor has become Disconnected from Earth Terminal ( Accessory is Full of Dust / Debris )

● Cables Routing Incorrect
● Loss of Ring-Circuit Continuity
● Conductor Overheating
● External Effects Not taken into Consideration
● Damaged Enclosures
● Faulty Equipment Manufacture

When Inspecting & Testing an Electrical Installation ! Ask Yourself

● Does the Installation Conform to the Latest Edition of the Electrical Wiring Regulations
● Has the Work been Carried Out Correctly an to Specification
● Is the Installation Safe to Use , in your Opinion ?
● Do you have Steps , Spare Parts , Other Equipment Available ?
● Have you Thought about your Own Safety and that of Others Around you , when Inspection & Testing
● Have all your Instruments been Checked Recently ( are they within Calibration Date )
● are you Aware of the Purpose of the Installation and all Circuits Within it ?
● Are you Familiar with the Test Sequence , and which Tests are Required
● Do you have All the Information you need to Carry Out the Task
● Are you able to Contact Customers , Sub-Contractors , Architects , Designers , Contact Mangers , etc If Further info is Needed
if so you’re Ready to Start !!

Visual Inspection Checklist ( Regulation 611.3
● BS-Standards Inspection , Does Everything Comply ( 511.1 / 511.2 ↔ Compliance with Standards ,
● Principal Visual Inspection ( 17 Checks / Not all Applicable ) Section 611 Reg , 12 / EAWR 1989 ( Risk Assessment )
● Connections 526.1 to 526 .9
● Identify Conductors 514 .3
● Cable Routing 512 .2
● Conductor Sizing ( Random Selection 524 & 525 ) incl , Voltdrop Allowance
● Polarity of Switches 132.14
● Polarity of ES Lampholders 612.6
● Protection against Thermal Effects & Presence of Fire-Barriers 131.3 & 527.1
● Electrical Shock Protection ( Pasic Protection 411
● Electrical Shock Protection ( Fault Protection 411
● Prevention of Common Damaging Influences 515
● Isolation & Switching Arrangements 537 ( ps it could be Manual Operation )
● Presence of Undervoltage Protective Devices 445.
● Position & Identification of Protective Devices 132.14 and 514
● Labelling 514
● Equipment and Protective Measures to External Influences 522
● Suitable Access – Equipment 513
● Presence of Danger Notices 514
● Availability of Diagrams & Notices 514
● Correctly Erected and Assembly of Equipment ( 133 , 134 , - part 5
● Drawings , Diagrams , Records , ( Previous Work )

Inspection Checklist BS-7671:2008

Confidence in Yourself – Never be Afraid to Ask or Seek Guidance if Required ,

Socket -Tester ( Measure the Effectiveness of the Earth ) the Earth Fault Loop Impedance ,

Heath & Safety ( GS-38 ) Mains Voltage Tester ,
Battery - Proving Unit A.C / D.C 50V – 690V 230V / 400V

Voltage Indicators should always be Tested with a Proving Unit or a Known Live Source Before and After Use
Zero Adjust ( Null ) Test Leads Résistance ……………………. ( R2 / Socket Adapter ) 4mm Tips on Leads
( Live Circuit Warning )

 

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Measurement of External Earth Fault Loop Impedance ( Ze ) 2392-10

The External Earth Fault Loop Impedance “ Supply Characteristics ” and Earth Arrangements
To be “ Recorded “ on the Second page of both the “ (i) (ii)

(i) Electrical Installation Certificate
(ii) Domestic Electrical Installation Certificate
(iii) Periodic Inspection Report

( Ze ) is the Earth Fault Loop Impedance of that path of the System which is External to the Installation

Like the Maximum Prospective Fault Current ( Ze ) can Only be Measured by Testing at the Origin of the Installation

Before the Test ,

( Lock Off with Padlock ↔ Key in you Pocket at all Times )
( Warning Sign must be Placed at the ( CU )

Main Switch ( OFF ) ( Earthing Conductor Temporarily Disconnected )

● ( Check the Polarity Indicator for Correct Connection )

● The Earthing Conductor must be Disconnected from the Main Earthing Terminal ,
● Must be Separated from all Parallel Earth Paths such as Bonding and Circuit Protective Conductors’
● Purpose of this Test is to Prove that the Intended Means of Earthing is Present and of an Acceptable Ohmic Value ,

For Safety Reasons ,
It is Essential that the Entire Installation is Isolated from the Supply before the Earthing Conductor ( or if Necessary ,
Any Other Protective Conductors’ ) are Disconnected from the Main Earthing Terminal ,
And that the Installation Remains Isolated for the Duration of the Testing

Providing Unit must be Used 1st
To Test the Probes of the Voltage Indicator are Working all right on Mains Power
● Voltage Indicators should always be Tested with a Proving Unit or a Known Live Source Before and After Use
Test the Probes of the Voltage Indicator that there’s No Power on the Feed Side

● Three - Phase Systems ,
Three - Lead Version (i) Green - Lead on Earth (ii) Red - Lead on Brown (iii) Black -Lead on Neutral
Two - Lead Version (i) Green - Lead on Earth (ii) Red - Lead on Brown
● Single - Phase Systems ,
Two - Lead Version (i) Green - Lead on Earth (ii) Red - Lead on Brown

● Test Instrument ( Set on “ Loop “ 20Ω
Earth Fault Loop Impedance Tester , ( this is a Live Test )

TT Systems , Where the Means of Earthing for the Installation is Provided by an Installation Earth Electrode ( the Value of Ze )

Two Methods of Measuring the Résistance of an Earth Electrode are Recognised in ( IEE Guidance Note - 3 )
● Method 1 , Using a Proprietary Earth Electrode Test Instrument , ←
● Method 2 , Using a Earth Fault Loop Impedance Test Instrument , ( Ra ) ←

The Test gives you (Ze) – this is ( Ra ) for your Electrode + the Résistance of the Supply Transformer Electrode + the
Transformer Windings Impedance + the Résistance of the Supply Line Conductors from the Transformer to the Input Side of
The Installation Main Switch , 411.5.3

( Ze = ( Ra ) for your Electrode + the Résistance of the Supply Transformer Electrode + the Transformer Winding Impedance +
The Résistance of the Supply Line Conductor from the Transformer to the Input Side of the Installation Main Switch

Note 2 ↔ 411.5.3 where ( Ra ) is not know it May be Replaced by ( Zs )

Verify Compliance with BS-7671 , Earth Fault Loop Impedance is Required for Each Circuit that Relies on ( ADS )
As the Protective Measure , 415.1.1

Without a Sufficiently Low Earth Fault Loop Impedance , the Magnitude of the Earth Fault Current will Not be Sufficient to Cause
The Protective Device to Automatically Disconnect the Circuit within the Maximum time Permitted to Provide Protection ,

Ohmic Résistance in Accordance BS-7671 ,
Earth Résistance
Selective Earth Résistance
Soil Resistivity

● Earth Fault Loop Impedance Table for TT Systems ( 41.5 ) 411.5.3

Rated Residual Operating Current I∆n mA 30 100 300 500Ω
Ra at 50v Ω 1667 500 167 100

Regs fig 2.5 / 2.3 / 2.4

Earth Fault Loop ( Zs ) paths for a TT Systems ( Supply Phase / Supply Neutral - Earth Electrode which is Electrically Independent of the Source

Earth Fault Loop ( Zs ) paths for a TN-S Systems ( Supply Phase , Separate Neutral & Protective Conductors throughout the System

Earth Fault Loop ( Zs ) paths for a TN-C-S Systems ( Supply Phase / Neutral & Protective Functions Combined in a Single Conductor
Part of the System , ( PME ) Protective Multiple Earthing ,

 

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2392-10 ( TT Domestic Measurement of Installation Earth Electrode Résistance

Method ( 2 )
Using an Earth Fault Loop Impedance Test Instrument
“ Set – Loop “ 200Ω

Main-Switch Off
Red-Lead ( Incoming Supply Brown Phase , ( L ) 514.8
The Earth Fault Loop Impedance Test Instrument is Connected to the Supply ( Energised ) Side of the Main Switch ←

Black Lead ( Connected to Disconnected Earthing Conductor )

(1) Access to the Equipment is Not Restricted ,
(2) Before Access to the Inside of the Distribution Equipment , Safe Isolation can be Preformed , ( Regulation 12 )
(3) Basic Protection meets the Required Standards ( IP Codes IP2X / or Exceeds ) 416.2.4
(4) Terminal Insulated Covers inside the CU , can Not be Displaced

Two Types of Protective Devices for Disconnection of the Circuit is Required for TT Systems , Fault Conditions -
(i) RCD (ii) Overcurrent Protective Device , ( RCBO BS-EN 61009-1 / RCCB BS-EN 61008-1 ) 41.5

Where an Overcurrent Protective Device is Used Regulation 411.5.4 -
( Requires following Conditions to be Fulfilled ( Zs x Ia ≤ Uo ) 32A ÷ 230v = Ω
RCBO BS-EN 61009-1 / RCCB BS-EN 61008-1 ) 41.5

(i) you must have your Earthing Conductor Impedance Low Ω as Possible
(ii) 411.5.3 - RCD is Used for Earth Fault Protection , ( TT System 0.2sec final Circuits “ Not Exceeding ” 32A , 411.3.2.2
(iii) 411.3.2.4 - 1sec , Final-Circuits / Distribution Circuits “ Exceeding ” 32A ( Ra x I∆n ≤ 50V )
TT Systems Only be Achieved by Protecting Every Circuit with RCD 411.5.3

Where Requirements , Regulation 411.5.3 are Meet if the ( Zs ) 41.5 Final Circuit Protected by RCD , Standards have been Meet ,
Maximum Disconnection , 411.3.2.2 / 411.3.2.3 TN- Systems , 411.3.2.4 TT – Systems ,

Fault Conditions – ( Earth Fault Conditions “ Ohms “ ( 230 ÷ Zs = Amps

For the Apprentice
“ Continuity of Protective Conductors “ ( Terminology “ Dead Test ” )

GN-3

612.2.1
No Load Voltage between 4 / 24V a.c / d.c
Short Circuit Current of Not Less than 200mA ( Ia > Ief )

“ Test Prior to the Installation Being Energized “
Test Instrument : Set on Continuity ( 20Ω )
The Resistance of the Test Leads is Significant
If the Particular Test Instrument does Not have Provision for “ Correcting for the Resistance ” of the Test Leads Measure the Résistance of the Leads when Connected Together , the Measured Value to be Subtracted from the Test Readings ,
( Terminology “ Wander Lead )
Test Instrument : Most New Instrument have ( Null Button this will Zero Out the Lead Resistance )
Measuring the Résistance of the Protective Conductor
Disconnecting where Practicable any Conductive Paths which may be Connected in Parallel to a Connection from a Protective Conductor to an Electrically Continuous Systems of Pipework at One or More Points along the Protective Conductor
Such Parallel Paths could Lead to Incorrect Test Readings and may even Conceal the Fact that a Protective Conductor is Not Electrically Sound ,
Some Instillations , with those Incorporating Metal Conduit or Metal Trunking which is Fixed to a Metal Structure
It would be Impracticable to Attempt to Disconnect all Parallel Paths
In such Circumstances , the Continuity of a Protective Conductor may be Verified only by Inspection in Addition to Testing

( R1 + R2 ) Method
This Method is Applicable to Circuit Protective Conductors and Line Conductors
Testing Continuity of a Protective Conductor to a Lighting Point One-Way –

“ Main Switch OFF “ ( Securely Isolate the Supply ) ↔ Regulation 12
(1) Temporary Connection , at the Supply End of the Circuit , at the CU between the Line and CPC of the Circuit to be Tested
(2) “ Red Lead “ on the Switch Live Terminal ,
(3) “ Black Lead “ on the Earthing Terminal ,
Polarity Should be Verified at Both the Lighting Point & the Switch ( CU ↔Link-Out ↔ Light Point ↔ Light Switch )
The Electrically most Remote Point in this Particular Circuit will be the Switch , ( R1 + R2 ) Value Recorded for this Circuit
Will be Measured at the Ceiling Outlet between the Switch Line and CPC ,

Testing Continuity of the Protective Conductor at a Lighting Switch by Wander Lead Method -
( R2 ) Black Lead on Earthing Terminal , Red on Earthing Terminal in Switch ,
Continuity Testing of a Ferrous Enclosure Using Wander Lead Method -
Black Lead on Earthing Terminal from one Back-Box , the Other Back-Box , Red Lead , PS, if there’s a Lot work a Pair at a Time back to the CU , ( R2) Ps if Not A ↔ B at the same time you doing , “ Visual Inspection “

At The Same Time your Checking Correct Polarity / with Continuity ,

If you keep thing Like this you’ll be a Great Tester one Day , 2391

GN-3
Heath & Safety ( GS-38 ) Mains Voltage Tester , 2mm / 4mm Tips on Leads ( with Fuse )
Battery - Proving Unit A.C / D.C 50V – 690V 230V / 400V
Voltage Indicators should always be Tested with a Proving Unit or a Known Live Source Before and After Use
Live Circuit Warning

For Apprentice to work on

612.2.2
Continuity of Ring Final Circuit

The Cables of a Ring Final Circuit Start at the Outgoing Terminals of the Consumer Unit
Connect to all the Points in the Ring , and Return to the Same Outgoing Terminals Live ( Line & Neutral ) Conductors
must Form a Complete Unbroken Loop without Interconnections ,
as Must the Circuit Protective Conductor ( CPC )

“ Securely Isolate the Installation “ ( EAWR ) Regulations 12 / 13
On the Part or the Installation to be Tested , Measure the Résistance of the Line & Neutral Conductors Separately ( between Ends )

Note Readings :
● End to end Résistance of the Line ( Live ) Conductor ↔ R1
● End to end Résistance of the Circuit Protective Conductor ↔ ( CPC ) R2
● End to end Résistance of the Neutral Conductor ↔ Rn
● Remember ( Neutral is Classed as Live Conductor , Ring Circuit End to End
on Ring : 2 x Live Conductors 2 x Natural Conductors 2 x Circuit Protective Conductors ( 4 Live Wires all in ) 2 x CPC = 6

314.1 Every Installation shall be Divided into Circuits
314.4 Where an Installation Comprise more than One Final Circuit , ( this is a Requirement – Part P )

This will Indicate Whether or Not the Conductors are Continuous , ( R1 + Rn )
Line ( Live ) & Neutral Conductors Should have Equal Résistance ,
Line – 0.40Ω
Neutral - 0.40Ω
CPC - 0.20Ω ( twin & earth 2.5mm2 ( R1 ) 2.5mm2 ( Rn ) 1.5mm2 ( R2 )

Performing the Test :
Set the Instrument on Continuity 20Ω ( Low Ohms (Ω) Continuity Range )
“ Main Switch OFF “

(i) Red Lead on : One End of Leg Phase
(ii) Black Lead on : One End of Leg Phase

(i) Red Lead on : One End of Leg Phase ( Phase & Natural on Terminal Block “ Cross-Connected “ )
(ii) Black Lead on : One End of Leg Neutral
This Test Sequence also Verifies Polarity & Circuit Protective Conductor Continuity to all Points in the Ring Final Circuit ,

● Probes , Voltage Tester ↔ GS-38
● Insulated ↔ Fused ↔ Finger Guards
● Maximum of 2mm & 4mm Exposed Tips / Retractable Shrouds

The Top Part of a Distribution Board must Conform to ( IP4X ) ← 416.2.2
The Sides of a Distribution Board must Conform to ( IP2X / IPXXB ) ← 416.2.4 (ii)

 

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Insulation Résistance 2392-10

Precautions May be Necessary to Avoid Damage to Electronic Devices ,
The Presence of any Circuit or Equipment Vulnerable to a Typical Test should be Indicated in the Diagram or Schedule of Test Results ,

Before Proceeding with this Test, the Inspector should Ensure that for the Circuit to be Tested
● All Pilot or Indicator Lamps that are Likely to Interfere with the Test , By Proving a Path between Line & Neutral have been Disconnected
● all Items of Equipment which are at Risk of Damage from the Test Voltage have be Disconnected ,
● Incoming Neutral has been Disconnected so that there is No Connection with Earth ,

“ Securely Isolate the Installation your Going to Work On , EAWR - Regulation 12
This Test should be Carried Out with all Circuits Isolated from the Supply and Confirmed Dead ,

● Locking Off Devices / Padlock , ( Warning Sign(s) Danger : Do Not Use )
Voltage Indicators should always be Tested with a Proving Unit or a Know Live Source before and After Use ,

● GS-38 is a British HSE Guidance Document , it is Advisory , Not Mandatory ,
The Standard for Safety of Test Equipment is BS-EN 61010 -

“ Dead Test “
Insulation Résistance Test Instrument , ( MΩ )
Capable of Supplying the Test Voltage D.C. Indicated in ( Table 61 )
Single-Phase Installation ( Line ( Live ) to Neutral )

Three-Phase Installation -
Line 1 to Line 2
Line 2 to Line 3
Line 3 to Line 1
Test each Line in Turn to the Neutral :

Insulation Résistance is Measured Between Live Conductors ( Line & Neutral ) a Voltage is Applied to the Conductors
● Check that all Switches are Closed ( Two-way Switches should be Operated to include all Live Conductors in the Test ,

TT Systems : Earth Electrode
Test Method for a New Installation : Before Connection to the Supply is Energized ,
Black Lead : Link Together all Line Conductor & Neutral
Red Lead : Linked Conductor(s) & Protective Earth ( Remember the MEM Link on Earth )

● Disconnecting the Earth from Earthing Terminal if you Do Not have a ( MEM Link on Earth ) Parallel Paths ,

“ Insulation Résistance Values “
● 0.00 MΩ = Dead Short ,
● 0.08 MΩ = Low Insulation Résistance Fault ,
● ≥ 200 MΩ = Healthy Circuit ,

● This Test is used to Prove that the Circuit under Tests has No Dangerous Short-Circuits Prior to the Circuit being Made “ Live ,
( Insulation Résistance ) ↔ This Test Verifies ( Proves ) that the Insulation of the Cables in Good Order ,

Insulation Résistance Tests Give an Indication of the Condition of the Insulation on the Installation ,
Effective Insulation is Required to Provide Basic Protection and to Prevent Short-Circuits & Earth Faults ,

Measure and Recorded the Results onto : Schedule of Test Results ,

For “ Circuits ” Rated at More than “ 100A “

The Use of D.C. Test Current may Lead to a Value of ( Zs ) Which is Optimistically Low and May therefore be Unacceptable
In Such Cases , an Ohmmeter or Continuity Test Instrument which Supplies an A.C. Test Current at a Frequency of ( 50 Hz )
Should be Used , Alternatively , a Value of ( Zs ) should be Obtained by another ( Method ) ( Such as Direct Measurement by an Earth Fault Loop Impedance Test Instrument ,

Measurement of ( Zs ) at a Socket-Outlet Using an Earth Fault Loop Impedance Test Instrument ,

Testing should Only be Carried Out after a Thorough Inspection and Continuity Testing have Confirmed ,
So far as is Reasonable Practicable ,
That all Circuit protective Conductors , and Main / Supplementary bonding Conductors are in Place ,

This Test is Conducted with the Supply On , all Necessary Precautions Must therefore be Taken to Prevent Danger
Earth Fault Loop Test Instrument : ( Set on Loop - 20Ω

For Socket-Outlets , as a Minimum , Perform the Test on the Outlet , Which is Situated Electrically Furthest from the Origin of the Circuit ,
If this is Not Know , Test all Socket-Outlets , in the Circuit and Record the Highest Value , Proprietary Test Lead with a Fitted Plug should be Used ,

TN-S : 0.8Ω

( Zs ) m ≤ 0.8 x ( Uo / Ia ) 230 ÷ 24 , 0.8Ω x ( Zs 9.58 = 7.67Amp

“ Measurement Earth Fault Loop Impedance “

Generally Accepted that , Where the Measured Earth Fault Loop Impedance of a Circuit is Not Greater than 80%
Of the Relevant Limit Specified in BS-7671
The Impedance can be Expected to be Sufficiently Low Under Earth Fault Conditions to meet the Relevant Limit Specified in BS-7671
And for the Protective Device to Automatically Disconnect within the Time Specified

41.2 / 41.3 & 41.4 BS-7671
Give the Maximum Permitted Values of ( Zs ) for Different Type of Overcurrent Protective Devices &
Different Maximum Permitted Disconnection Times , Maximum Permitted Values Given in BS-7671
Are Based on the Conductors having been Heated up by the Passage of Load Current , which Increased their Résistance
Whilst Test Results are Usually Obtain when the Conductor Temperature is Lower ,
Correction Factors is Given in IEE Guidance Note 3 / 6
“ As a Rule of Thumb “ the Measured Values of ( Zs ) should Not Exceed ↔ 0.8 times ↔ the Relevant Values Given BS-7671 ( 41.2 & 41.4 )

It is Generally Necessary to Adjust the Values Obtained by the Test before Comparing them with the

the Limiting Values of Earth Fault Loop Impedance when Measured at Ambient Temperatures up to 20ºC
the Limiting Measured Values are 80% of the Values given in BS-7671 , Round Down ,

the Value to be Recorded in the Schedule of Test Results is the Measured Value ,

if the Protective Device is Not of a Type whose Maximum Permitted ( Zs ) Value is Given in BS-7671
then , as a Rule of Thumb , the Measured Values should Not Exceed ↔ 0.8 times ↔ the Value Given by the Formula
Appendix 3 BS-7671 p-243

Zs = Uo / Ia ( 230 ÷ 32A = 7.18Ω )

PFC ( 230 ÷ 1.16 = 198A )

2392-10
Domestic Electrician
New Installation your Using Cold Test Only OSG , 2D ( 80% )