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

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“ 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

 

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● 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.

 

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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 :

 

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“ 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 ← ←

 

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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 ,

 

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● 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 )

 

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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 )

 

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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)

 

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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 ,

 

[amberleaf]

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 ,

 

[amberleaf]

● 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 )