Re-take - Useful Information for 2394 :

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A “ duty of care ” responsibility makes the test engineer a “ duty holder ” for the duration of the inspection and testing process

The tile in law placed upon the test engineer is that of “ duty holder ”

2394 / 2395
The “ duty holder ” used in the Electricity at Work Regulations refers to the person . (( responsible for the electrical installation ))

The Electricity at Work Regulations identifies anyone taking control of, or responsibility for, an electrical system as a “ duty holder ” ( Memorandum of Guidance Regulation 3 item 55 ) “ duty holder’s ” have a duty to ensure the safety of themselves and others .

 

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Facts . :13:
As an Inspector to be . 2394 .

(IET) is the largest multidisciplinary professional engineering institution in the world.

Non-statutory
The Guidance Notes are published by the Institution of Engineering and Technology and are intended to be explanations of the requirements of BS-7671:2008(2015)

As the Guidance Notes are for “ Guidance ” only they must not be used independently of BS-7671:2008(2015) for ensuring compliance .

Guidance Note 3 is based upon the requirements of Part 6 in BS-7671:2008(2015)

As part of the competence requirement, the inspector must have a sound working knowledge of the test methods as described in the Guidance Note.

it provides details of the methods to be used for carrying out the tests as required by BS-7671:2008(2015) for both New and Old installations, it also provides detailed inspection check list to comply with the requirements and gives details of the instrument(s) to be used when carrying out the testing process .

 

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Appendix 6 ( informative ) P/413 refer :juggle2:

Certification and Reporting

So there is no screw ups in wording from : BS-7671:2008(2015) & GN-3 . in Exams .

(i) The Electrical Installation Certificate required by Part 6 should be made out and signed or otherwise authenticated by a ( skilled person or persons ) Etc .
(ii) The Minor Work Certificate required by Part 6 should be made out and signed or otherwise authenticated by a ( skilled person or persons ) Etc .

(iii) The Electrical Installation Condition Report required by Part 6 should be made out and signed or otherwise authenticated by a ( skilled person or persons in respect of the inspection and testing of an (( existing installation ))

(iv) Skilled persons will, as appropriate to their function under (i) (ii) and (iii) above , have a sound knowledge and experience relevant to the nature of the work undertaken and to the technical standards set down in these Regulations , be fully versed in the inspection and testing procedures contained in these Regulations and employ adequate testing equipment .

 

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The English language has three basic tenses: past, present, and future.

Amendment 3 of BS-7671:2008. is expected to be published on the 1st January 2015 and is intended to come into effect on 1st July 2015.

From January 2015, the 2382-15 . 17[SUP]th[/SUP] Edition becomes the only 17[SUP]th[/SUP] Edition qualification available as the older 17[SUP]th[/SUP] Edition course is being retired.
Electricians will need to update their qualification to the new 17[SUP]th[/SUP] Edition by July 2015 in order to stay current.

Periodic inspection and testing . ( look at the dates )

GN-3 (BS-7671:2008,2011,(2015)
Purpose of periodic inspection and testing

(2008) The purpose of periodic inspection and testing is to provide, so far as is reasonably practicable, for .

3.1. (2011) The purpose of periodic inspection and testing is to provide an engineering view on whether or not the installation is in a satisfactory condition where it can continue to be used safely .
3.1. (2015) The purpose of periodic inspection and testing is to provide an engineering view on whether or not the installation is in a satisfactory condition where it can continue to be used safely .

3.8. GN-3 (BS-7671: 20112015)
Requirements for inspection and testing .

The purpose of periodic inspection and testing is to provide an engineering view on whether or not the installation is in a satisfactory condition where it can continue to be used in a safe way .

GN-3 (BS-7671: 2011,(2015)
1.4. Additions and alterations . 132.16. 633.1. 633.2.

Every addition or alteration to an existing installation must comply with the current edition of BS-7671: and must not impair the safety of the existing installation. In this respect, in order to verify that the addition or alteration to an electrical installation complies with BS-7671: the existing installation must be inspected and tested to confirm the safety of the addition or alteration, including for example.

• protective conductor continuity
• earth fault loop impedance

633.2.
Whilst there is no obligation to inspect and test any part of the existing installation that does not affect and is not affected by the addition or alteration, observed departures are required to be noted in the comments box of electrical installation certificates (single-signature or multiple-signature) and minor work certificates .

(BS-7671: 2011,(2015)
132.16 - Additions and alterations to an installation

No Additions and alterations, temporary or permanent, shall be made to an existing installation, unless it has been abstained that the rating and the condition of any existing equipment, including that of the distributor, will be adequate for the altered circumstances, Furthermore, the earthing and bonding arrangement, if necessary for the protective measure applied for the safety of the addition or alteration, shall be adequate.

 

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Learning curve. Only

Basic voltage drop calculation

Single-phase
To calculate the voltage drop in volts the tabulated value of voltage drop ( mV/A/m) form Appendix 4 of BS-7671: has to be multiple by the design current of the circuit (Ib) the length of run in metres (L) and divided by 1000 ( to convert to volts )

Voltage drop = ( mV/A/m) . L Ib

Where :
( mV/A/m) tabulated value of voltage drop in mV per amp per metre form Appendix 4 of BS-7671:
L) the length of run in metres (m)
Ib) design current of circuit (A)

The requirements of BS-7671: are deemed to be satisfied for a 230V supply, if the voltage drop between the origin of the installation and a socket-outlet or current-using equipment does not exceed at full load 5% of 230V that is 11.5V.

for final circuits in particular for domestic installations ( mV/A/m) . L Ib
Power - 5% x 230V = 11.5V
Lighting - 3% x 230V = 6.9V .... 230V x 3% ÷ 100 = 6.9V etc .

Cooker circuit with ( Ib of 32A ) installed in conduit in an insulated wall . from 4D5A . ( T&E ) cable .
Method A* Colum 7 , a 6mm[SUP]2 [/SUP] cable is selected . from column 8 . this has a voltage drop ( per ampere per metre ) of 7.3 mV/A/m . if the length of cable is 10m then the voltage drop is :

(mV/A/m). L Ib / 1000 = (7.3) x 10 x 32 / 1000 = 2.3V . Q) is this less than 11.5V

 

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Learning curve only .

The effect of temperature upon conductor résistance

Copper has a positive coefficient . i.e. the warmer the cable the higher its résistance

The résistance tables for copper sizes are based upon an ambient temperature of 20°C and the résistance of copper cable increases by 0.004Ω per degree rise .

i.e. if a coil of cables temperature increases by 5°C , the corresponding increase in résistance will be 0.02Ω ( i.e. 5 x 0.004)

Value of résistance / metre for PVC insulated copper conductors and of ( R[SUP]1[/SUP] + R[SUP]2 [/SUP] ) per metre at 20°C in milli-ohms / metre .
GN-3 table B1 .
O.S.G. table 11 .

Where the résistance of a cable is measured at an ambient temperature other than of 20°C and the length is required, a correction factor must be used.
it must be ensured that when the circuit length etc. needs to be obtained, the values used in the calculations must be at the same temperature, i.e. either

Change the values in the résistance table at 20°C to whatever temperature the résistance measurement was taken at ( 5°C / 10 / 15 / 20 / 30 / 35 / 40°C )
GN-3 table B2 . goes up to . 5°C / 10 / 15 / 20 / 30 / 35 / 40°C
O.S.G. table 12 . goes up to . 5°C / 10 / 15 / 20 / 25°C

What does not change with the increase in temperature is its length .
Consider the 1mm[SUP]2[/SUP] cable . ( 20°C / 100m ) ◄

O.S.G. table 11 . The résistance for 1mm[SUP]2[/SUP] PVC insulated copper conductors at 20°C is 18.10 mΩ / m .
(∴) the total résistance of the cable 100 x 18.10 / 1000 = 1.81Ω
O.S.G. table 12 . the résistance / metre for 1mm PVC insulated copper conductors at 25°C is 18.10 mΩ / m x 1.02

(∴) résistance of the cable at 25°C = 100 x 18.10 x 1.02 / 1000 = 1.846Ω

O.S.G. table 12 .. Expected ambient temperature (°C) followed by , Correction factor ( applied to 20°C table )

if I loose the symbol (∴) therefore .

 

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BS-7671:2008(2015) :icon_bs:

There are now ( 20 ) Special Installations or Locations .

Q) Where will we use the IP code , The answer’s lies in BS-7671:2008(2015)
Requirements for Electrical Installations

Example Only .
Part 7 . Special installations or locations .
P/236 - 709.553.1.13. (( 709 / 553 / 1.13 ))
709 ) Marinas and similar locations etc.
553) This bit refers to the section in Part 5 ( 553 ) Accessories .
1.13) And this is the regulation, or series , regarding Plugs & Socket-outlets

Section 700 General .

The higher the IP rating the more protected the light will be.

Section 701 Locations containing a bath or shower
“ Zonal ” concept is based on the perceived risk of electric shock . ( 0, 1, 2, ) in relation to areas in / around the bath .
Having established the zones, particular requirements are then prescribed for:
switchgear
controlgear
accessories
current using equipment .

IPX7 , IPX4

Section 702 Swimming pools and other basins
702.512.2 - Electrical equipment shall have at least the following degree of protection according to BS-EN-60529:
IPX8 , IPX5 , IPX4 , IPX2 .

Section 703 Rooms and cabins containing sauna heaters
IPX5 , IPX4 .

Section 704 Construction and demolition site installations
Section 705 Agricultural and horticultural premises - IPXXD or IP44
Section 706 Conducting locations with restricted movement
Section 708 Electrical installation in caravan / camping parks and similar locations - IPX4 or IP3X
Section 709 Marinas and similar locations - IPX6 , IPX5 , IPX4 .
Section 710 Medial locations
Section 711 Exhibitions, shows and stands - IPXXD or IP4X .
Section 712 Solar photovoltaic (pv) power supply system
Section 714 Outdoor lighting installations - IP33
Section 715 Extra-low voltage lighting installations
Section 717 Mobile or transportable units - IP55 , IP44.
Section 721 Electrical installations in caravans and motor caravans - IP44
Section 722 Electric vehicle charging installations - IP44
Section 729 Operating and maintenance gangways
Section 740 Temporary electrical installations for structures, amusement devices and booths ............ IPXXD or IP4X
Section 753 Floor and ceiling heating systems - IPX1 , IPX7

IPX1. This will protect a device from some water drops that are falling vertically.

 

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Learning curve only . You have to study it yourself . ( IP Codes ) :book:

The two most popular used IP codes in BS-7671: are - IP2X / IP4X

The IP code is one method of checking to see if equipment is suitable for any particular area of risk.

(A3):2015 - Appendix 1 (Normative)

P/305 (A3) . BS-EN-60529:1992(2004) + A2:2013 .
Specification for degrees of protection provided by enclosures (IP code)

Index of protection is a code which gives us a means of specifying the suitability of equipment for the environmental conditions in which it will be Used .
527.2.3(i) & (ii) . 702.512.2 708.512.2(i) & (ii) . 708.55.1.8. A721.55.6. A721.55.10.

Basic protection
Barriers and enclosures are used to prevent contact with “ live parts ”
BS-7671:2008(2015) 416.2.2.
requires that readily accessible horizontal top surfaces of barriers and/or enclosures provide a degree of protection of at least IP4X or IPXXD

No access to live parts
BS-7671:2008(2015) 416.2.4.
Also requires that “ live parts ” shall be inside enclosures or behind barriers providing a degree of protection of at least IP2X or IPXXB

(iii) Where removal of a intermediate barrier providing a degree of protection of at least IPXXB or IP2X prevents contact with “ live parts ” by the use of a key or tool to remove the intermediate barrier.

For IPXXB
Full penetration of the British Standard test finger to a maximum of 80mm, the test is the same as that stated in IP2X and the finger must not come into contact with hazardous parts to comply to this requirement

If the installation passes IPXXB then it also passes IP2X

Degrees of Protection Provided by Enclosures (IP Code)
Document Number : BS EN 60529
Publication Date : 1992:

Gives uniformity in methods of describing the protection provided by enclosures and in tests to prove various degrees of protection. Provides an optional extension of the IP code by an additional letter A-D, if the actual protection of persons against access to hazardous parts is higher than that indicated by the first characteristic numeral.

Occasionally, you will see an IP code with an extra letter on the end: this is optional, and stands for ' other protections '.

Enhanced protection
IPXXA - 50mm sphere pressed against all openings to prevent ( Touching live parts with back of hand )
IPXXB - 12mm test finger and 80mm in length to prevent ( Touching live parts with a finger )
IPXXC - Access by probe 2.5mm diameter and 100m in length to prevent ( Touching live parts with a tool )
IPXXD - Access by probe 1mm diameter and 100m in length to prevent ( Touching live parts with a wire )

IP Codes for Beginners

IP rating details

Solid particle protection
0 - no protection at all
1 - Protects against objects larger than 50mm, like a fist - but if you put a little effort into touching the item in question, you won't be protected
2 - Protection against objects larger than 12.5mm like fingers
3 - Protection against objects larger than 2.5mm like tools, thick wires or your keys
4 - Protection against objects larger than 1mm, which includes most wires, screws, and anything else you may try to poke into the machine
5 - Dust protected: this provides complete protection against contact, and also prevents dust entering in quantities large enough to cause problems
6 - Dust tight: even the finest dust will give up in disgust.

 

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Learning curve only . You have to study it yourself . ( IP Codes ) :book:

Liquid ingress protection
0 - No protection
1 - Vertically falling water drips will not harm the equipment (equivalent to 1mm of rainfall per minute)
2 - Vertically falling water drips will not harm the equipment if it's tilted at an angle up to 15° (equivalent to 3mm of rainfall per minute)
3 - Protected against drops of water falling at up to 60° from the vertical
4 - Protection against spraying water at a pressure of 80-100kPa
5 - Protection against splashing water at the same pressure
6 - Protection against powerful jets of water
7 - Protection against water ingress when the object is immersed in up to one metre of water
8 - Protection against water ingress when the object is immersed in more than one metre of waterProtection against spraying water at a pressure of 80-100kPa

The 'other protection'
Letters A-D detail specific items that cannot penetrate an item. The final four letters simply give a little more information about the test conditions that led to the IP rating assigned.
A - Back of hand
B - Finger
C - Tool
D - Wire
H - High-voltage device
M - Device moving during water test
S - Device standing still during water test
W - Weather conditions

Example: 100A 20 way plastic consumer unit . ( obsolete now )
Top wall removes easily to provide cable access and reseals to IP4X

These ratings are determined by specific tests. Sometimes you will see IPX4 or IP4X. The (x) is used when the corresponding number is not required. For example: IP2X (the industry standard finger test) denotes that you cannot touch or gain access to live parts with your finger.

 

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My own take . Short. version
IPXXB, is the IP code for the degree of protection that must be provided once the cover is off a distribution board or consumer unit.

IP2X is the level of protection with cover in place .
IPXXB is with cover removed .

 

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O.S.G.

2008:
2011:

10.2.2. With the supply connected
vi ) check polarity of supply, using an approved voltage indicator .

(A3) 2015 10.2.2. (With) the supply connected and energised .
GS-38 (f) check polarity of supply, using an approved voltage indicator

 

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C&Gs - Level 3 Award in the Initial Verification of Electrical Installations (2394) February ( 2014 ) ◄ :svengo:

Leaning outcome

The leaner will:

6. understand the requirements for testing energised installations.
6.1 State the procedures for confirming polarity of the incoming supply. ◄

Re-cap .
Polarity is correct at the intake position @ consumer unit or distribution board ... Confirmation of supply polarity [✓]

Polarity .. two-methods
Dead testing . (Continuity method)
Live testing . an approved voltage indicator or test lamp

-&-s . Identify the test that should be applied to verify polarity after the supply is energised
Test to verify correct polarity of the incoming ( live-supply ) ............. test made at the Origin

O.S.G. (2015) P/105. Polarity
GS-38 . After connection of the supply, correct polarity must be confirmed using an approved voltage indicator or test lamp
( in either case with leads complying with the recommendations of HSE Guidance Note GS-38 )

Past tense ( check the dates )

GN-3 check polarity using an approved indictor
2008: P/46 2.7.11. ..... Polarity
After connection of the supply, polarity should be confirmed using an approved voltage indicator ( test made at the Origin )

► 2011: P/47 2.7.12. ..... Polarity testing
The polarity of all circuits must be verified before connection to the supply .

► 2015: 2.6.13. ..... Polarity testing
The polarity of all circuits must be verified before connection to the supply . refer

GN-3 referring too . Polarity testing
Alternatively. polarity can be verified by visually checking core colours at terminations thus verifying the installer’s connection. Whatever method is used, polarity checks are required at all points on a circuit.

Certification and Reporting

P/414 .. Electrical Installation Certificate (EIC)
Confirmation of supply polarity [✓]

P/424 .. Electrical Installation Condition Report (EICR)
Confirmation of supply polarity [✓]

P/417 .. Minor Electrical Installation Work Certificate (MEIWC)
Polarity satisfactory [✓]

( Point to note here )
Supply is connected .. Polarity “ Confirmation”

You will see that BS-7671:2008(2015) Regulations & Standards as the document against which a professional judgement needs to be made. ( That is why the wording changed in ( 2015) Skilled person ( electrically)

Q) Does the R1 + R2 test confirm the correct polarity of a radial circuit .
No, not on its own. Whilst the test can provide an indication of polarity, it needs to be combined with inspection and further testing as required by Part 6 of BS-7671: 2008:

Regulations . it comes under the heading off - Initial Verification ... 611.3. 612.6.




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One of the simplest of question’s -&-s ask you .

State :
the maximum rating of the RCD. the maximum disconnection time and the applied test current as required by Regulation 415.1.1, in BS-7671:20082015)

- Maximum rating 30mA
- Maximum disconnection time 40mS
- Maximum test current up to five times the maximum rating. i.e. 30mA x 5 = 150mA

The Regulations have to state the facts .

415.1.1
The use of RCDs with a rated residual operating current (IΔn) not exceeding 30mA and an operating time not exceeding 40mS at a residual current of 5 IΔn is recognized in a.c. systems as additional protection in the event of the provision for basic protection and/or the provision for fault protection or carelessness by users .

 

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re-cap .

RCDs used in BS-7671:20082015)
Typical uses and maximum ratings for residual current devices

► 30mA - final circuits supplying socket outlets on agricultural premises.
► 100mA - final circuits for socket-outlets in excess of 32A on agricultural and horticultural premises
► 300mA - protection against fire .
► 500mA - final circuits for socket-outlets in excess of 32A on construction site. P/223 .

Section 705
705.411. Protective measure: Automatic disconnection of supply .... ( ADS)

705.411.1. General
In circuits, whatever the type of earthing system, the following disconnection devices shall be provided:
(i) In final circuits supplying socket-outlets with rated current not exceeding 32A, an RCD having the characteristics specified in Regulation 415.1.1.
(ii) In final circuits supplying socket-outlets with rated current more than exceeding 32A, an RCD with a rated residual operating current not exceeding 100mA .
(iii) In all other circuits, RCDs with a rated residual operating current not exceeding 300mA .

 

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RCDs

Additional Protection.

Additional protection by Residual current devices .
The use of an RCD whose rating (IΔn) does not exceed 30mA and disconnects within 40mS when tested at 5 x IΔn is recognised as providing .

- Additional protection against the failure of basic protection .
- Additional protection against the failure of fault protection .
- Additional protection against carelessness by users .

415.1.1 :icon_bs:
The use of RCDs with a rated residual operating current (IΔn) not exceeding 30mA and an operating time not exceeding 40mS at a residual current of 5 IΔn is recognized in a.c. systems as additional protection in the event of the provision for basic protection and/or the provision for fault protection or carelessness by users .