2394: (T) Regulation - 132.13. . p.20
“Every electrical-installation shall be provided with (Appropriate-documentation ) including that by . Regulation - 514.9 . Part-6 . and where applicable - Part - 7 “


 
2394: Regulation - 131.3.2. Down-lights . ( Roomfor Thought )

Persons. livestock . fixed-equipment and fixed-materials ( Adjacent to electrical-equipment ) shall be protected against harmful-effects of Heat or thermal-radiation emitted by electrical-equipment .

- Could combustible-dust and debris build up behind the Lights . !!!!

The ( Most - common ) Older-lath and plaster ceilings . sawdust or split-timber laths remaining . ( Couldthe light-fitting(s) become in contact with the down lights .

Facts:
i). Combustion . ignition or degradation of materials’ .
ii). Risk of burns .
iii). Impairment of the safe-function of installed-equipment .

Regulations tells us . Electrical-equipment shall Not - present a fire-hazard to adjacent-materials’ .


 
The ( Most - common ) Older-lath and plaster ceilings . sawdust or split-timber laths remaining above the light - fitting . become in contact with the down lights .

 
2394: Problems . Down-lights .

Most-common when Open-backed-recessed-light-fittings . are being used. - Could combustible - dust and debris build up . Heat . you nothe rest .
 
2394: Down-lights . ( Room for Thought )

Regulation- 522.2.1. External - heat - sources .

In order to avoid the effects of ( Heat !! Cables ) from external-sources . on or more of the following- methods or an equally-effective-method shall be used to prevent a wiring - system .

i). Shielding .
ii). Placing sufficiently far from the source of Heat . ( Cables. Not resting over the down-light . ) Etc ..
iii). Selecting a system with due regard for the ( Additional -temperature - rise) which may - Occur .


 
ApprovedDocument P - Building Regulations . 2008:

Designand Installation . - ( Applying to Dwellings )
Regulation- P1 .
“Reasonable provision shall be made in the design and installation of electricalinstallations in order to protectpersons operating . maintaining or altering the installations from . fire or injury .

Firstly : 134.1. - Erection . Strictly only applies to Erection not Design .

BS-7671:2011: Are - reminding Us .
Regulation- 134.1.1. Good workmanship by competent-persons or persons under their supervisionand proper-materials shall be used in the erection of the electrical-installation. Electrical - equipment shall be installed in accordance with the ( Instructions provided by the manufacturer of theequipment )

Manufacturer’s- Instructions

As electrician’s . ( weve all fallen ) into the trap of not reading the instruction-leaflet supplied with equipment . after all . who needs instructions for things that we have done countless timesbefore .

Misconception- that any experienced-electrician will not need this Guidance . This is clearly not the case . since -differing - products . from differing Manufacturer’s. installed in different-locations will have quite-unique requirements thatshould be considered and implemented .

Inall cases . by simply following . Manufacturer’s - Instructions gives us a ( Fall - back - position ) should something fail or cause a problem. This if nothing-else. will assist the electrician in protecting his or her ( future-liability )

Regulation- 132.13 .
“Every electrical - installation shall be provided with appropriate-documentation. including that required by . Regulation - 514.9. Part - 6 and where applicable . Part - 7 .

Re-cap: Part - P : Extracts’
Installations in dwellings . to operate at a . Low or Extra-low-voltage . The Extra-low-voltage-band was included to cover such things as . Extra-low-voltage downlights . caused of a number of house - fires .

Some- Facts . 2394: “ Downlights “
- Theproblem and risk is further-compounded by the facts that some-lamp-types are designed to ( Direct ) much of their heat out of the back - ( Dichrioic-type) :banghead:
-Whilst others are deigned to direct their heat ( Forward ) - ( Aluminium-reflector-type ) :svengo:

 
Regulation must - State the Facts .

If you don’t use it you lose it . 2008:

When considering is . supplementary-bonding . canbe Omitted from a location containing a . bath or shower . the Maximum-résistance . of Extraneous-conductive-parts connected to the . ( MET ) main-earthing-terminal . 415.2.2.

• 1.666Ω .
• 0.05Ω .
• 0.5Ω .
• 6.5Ω .

Useful-Junk. Additional-protection - Supplementary-equipotential-bonding .

415.2.2. Where doubt exists .
Regarding the effectiveness of Supplementary-equipotential-bonding. it shall be confirmed that the résistance ( R ) between simultaneously accessible . Exposed-conductive-parts and . Extraneous-conductive-parts . fulfils the following-condition :

R ≤ 50 V /Ia . in a.c. - systems .

Where ( Ia ) is the operating-current in ampere’s of the protective-device . - for RCDs - IΔn . for overcurrent-devices . the current causing automatic operation in 5s .

RCD - 30mA ÷ 1000 = 0.03A .

Example - 1 : Scenario . that the protective-device is an RCD - rated at 30mA . [ R ≤ 50V / Ia ]
R ≤ 50V / 0.03A = 1.666Ω . [ R ≤ 1.666Ω ]

Therefore. a maximum-résistance of 1.666Ω will ensure there is sufficient-current to operate the RCD .
Note : that the touch-voltage may rise above 50V . the value of 50V is used as a constant in the formula to ensure . sufficient-current is following to operate the RCD.

Example - 2 : Scenario . that the protective-device is a .BS-EN-60898 - Type - B circuit-breaker . rated at 32A . first we must establish the current causing operation of the circuit-breaker by referring to the correct . time / current - characteristics graph in Appendix- 3 of BS-7671:2008:2011: therefore . looking at fig- 3.4 . 3.4A . p.249 / 301 . some of us still have marking on 2008 : we can establish that the current-causing-operation of the circuit-breaker is 160A .

[ R ≤ 50V / Ia - R ≤ 50V / 160 - R ≤ 0.31Ω ]

Therefore. a maximum-résistance of .0.31Ω will ensure there is sufficient current to operate the circuit-breaker within five-seconds .

fig- 3.4 . 3.4A .
The current-causing operation of the device between . 0.1 & 5s isthe same . this will not be the case for . “ Fuses “ if many circuits are present in a particular area . and are protected by different-protective-devices / types . etc . the worst-case characteristics should be used .

GN-3: advises that the résistance of Supplementary-equipotential-bonding-conductors. should be no more than ( 0.05Ω ) when verifying Supplementary-equipotential-bonding-conductors. Regulation - 612.2.1. requires that a continuity-test be made with a recommendation that the test-instrument has a .non-load voltage of between . 4V and 24V d.c. or a.c. and a short-circuit-current of .not less than 200mA .

Re-cap: Regulation - 701.415.2. . Supplementary-equipotential-bonding . the regulation states that where the location containing a bath or shower in abuilding with a protective equipotential-bonding system in accordance with . Regulation - 411.3.1.2. Supplementary-equipotential-bonding . may be omitted where all of the following conditions are met .

iv) . all final-circuits of the location comply with the requirements for automatic-disconnection according to . Regulation - 411.3.2.
v). all final-circuits of the location have additional-protection by means of an RCD . in accordance with . Regulation - 701.411.3.3.
vi). All - extraneous-conductive-parts of the location are effectively connected to the protective-equipotential-bonding accordance to . Regulation -411.3.1.2.

this means the Inspector . needs to make an assessment that all . extraneous-conductive-parts of the location are effectively connected to the. protective- equipotential-bonding .according to - 411.3.1.2.

Note: the effectiveness of the connection of . extraneous-conductive-parts in the location to the . main-earthing-terminal may beassessed . where necessary . by theapplication of Regulation - 415.2.2.

Regulation- 415.2.2. States .
Where doubt exists regarding the effectiveness of Supplementary-equipotential-bonding. it shall be confirmed that the résistance ( R ) between simultaneously-accessible . exposed-conductive-parts , and extraneous-conductive-parts . fulfils the following conditions: [ R ≤ 50V / Ia . in a.c. systems ] where .

Ia . is the operating-current in amperes of the protective-device for RCD . ( IΔn ) for overcurrent-devices .the current causing . automatic-operation in ( 5s )


















 
Continuity - confirmed :

During any verification process to confirm the soundness ofan electrical installation - whether it be a new installation, an alteration oraddition, or whether examining the condition of an existing installation - thecontinuity of conductors has to be confirmed.

The requirements of Regulation - 612.2.1 and Regulation - 612.2.2 of BS7671:2011: regarding the continuity ofprotective conductors are generally well understood. However, the implicationsof not testing the line and neutral conductors for continuity are often notfully appreciated.

Why do we carry outcontinuity-tests :

Firstly, it is to ensure that any earthing system is acontinuous and a low resistance path to allow the passage of fault currents ofsufficient magnitude to operate the protective device during fault conditionswithin the required disconnection time.

Secondly, confirmation of the “ zero ” potential between metal parts, both extraneousand exposed-conductive-parts, within an installation to reduce the effects ofelectric shock for the user of the electrical installation.

Thirdly, that the conductors, including all line and neutralconductors, are connected in the correct sequence for safety and foroperational purposes.

Polarity,
Although not directly part of continuity testing, doesfacilitate the confirmation that conductors are continuous and connected in thecorrect sequence.
Earth fault loop impedance testing is part of the (
Verification processof the continuity of the conductors ) , although this test on its owndoes not prove that all conductors are continuous.


One of the areas that are oftenoverlooked is the continuity of neutral conductors. ( Apartfrom ring final circuit continuity testing ) , there is no requirement in BS 7671 toverify the continuity of neutral conductors. Nor is there any facility in thecertificates to record neutral continuity.
( ring final circuit continuitytesting ) Generic schedule of test-results . p.402 . Ring-final-circuit-continuity - L . N . CPC .

2394: Condition of circuit-accessories -621.2. (iii) confirmation that the installation is notdamaged or deteriorated so as to impair-safety . PIR .

- Operation of main-switches- function - check . 612.13.2.
Equipment . such as switchgear and controlgear assemblies .drivers . control and interlocks . shall be subjected to a functional-test . to show that it is properlymounted . adjusted and installed in accordance with the relevant requirementsof these Regulations .

- Manual operation of circuit-breakers. & RCDs to provide disconnection - 612.13.2.
 
Useful - Junk

New numbering system introduced for UK - only national regulations
Amendment - 1 :2011: . UK national regulations will end in [ 100 . 101 . 102 ] Etc 522.6.102 .

The reason : This will show regulations that are specific to the UK - only . and Not used in the EU . :icon_bs:
 
The structure of the newElectrical Installation Condition Report (EICR) remains the same - it has thereport pages and associated schedule of inspections and schedule of testresults. All of these are included in what ? Isit:

A - Model forms in Appendix 7 of BS 7671:2008(2011)
B - Model forms in Appendix 6 of BS 7671: 2008(2011) p.389
C - New section 710 of BS 7671:2008(2011)

A - Model forms in Appendix 7 of BS 7671:2008 (2011)- [ Harmonized cable core colours ]
C - New section 710 of BS 7671:2008(2011) - [ Medical locations ]

2394 : • What should be recordedin the summary of observations section ( K ) on the report ? Is it:

Answer - One of the following codes . as appropriate . has been allocated to each of the observations made. Etc

A - Any C1, C2 or C3 classification code - p.397
B - All C4 classification codes
C - The new C5 classification code (as well asall others)
 
What ties in with Regulation ( 15 ) ofthe Electricity at work Regulations ? Isit:

A - The European form from CENELEC
B - Section 534 - Devices for protectionagainst overvoltage
C - Section 729 - Operating / maintenancegangways

Mainly concerning . Electrical-switch-rooms .and Restricted-areas . this amendment ties in with . Regulation - 15 . of the Electricity at work Regulations and includes requirements for working-spaces . gangway width . operational-access . emergency-access. and emergency-evacuation .
 
TheElectricity at Work Regulation 1989 . :welcome2:

Persons involvedin electrical installation work must be [ Competent ]
TheElectricity at Work Regulation 1989 imposes duties on persons involved in electrical-work. whether employers . the self-employed or employees . including most trainees.

Regulation- 16 . [ Persons to be competent to prevent danger and injury ] states “ No person shall be engaged in any work activitywhere 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 ofsupervision as may be appropriatehaving regard to the nature of the work ]

TheMemorandum of guidance on the . Electricity at Work Regulation 1989 - [ HSR25.HSE: 1989 ] states that “ the object of the regulation is to ensure that personsare not placed at risk due to a [ Lack of Skills on the part of themselves or others in dealing withelectrical equipment ]

The [ Scope of technical-knowledge or experiencemay include ]

Adequate knowledge of electricity .
Adequate experience of electrical work .
Adequate understanding of the system to beworked on and practical experience of that class of system .
Understanding of the hazards which may ariseof the hazards which may arise during the work and the precautions which needto be taken .
Ability to recognise at all times whether itis safe for work to [ continue ]

Regulation- 110.1.1. apply to the . design . erection and verification ofelectrical-installations such as theses of :

i) residential-premises .
ii) commercial-premises .
iii) public-premises .
iv) industrial-premises . Etc .

Legislation 2394: That we must work under . The BuildingRegulations of England and Wales. this is the one am working- of 2008 .

A dwelling isa place of work when work is undertaken . ThisAct empowers the Secretary of Sate to make regulations . The most relevant toelectrical-installation work are :

- TheElectricity at Work Regulation 1989 .
- Healthand Safety at Work . Act - 1974 .
- Managementof Health and Safety at Work Regulations - 1992 .
- Construction( Design and Management ) Regulations - 2007 .
-Provision and Use of Work-equipment Regulations - 1998 .
- PersonalProtective Equipment at Work Regulations - 1992 .
- ElectricitySafety . Quality and Continuity Regulations - 2002 .
- Construction( Heath . Safety and Welfare ) Regulations - 1996 .

Legislation 2394:

- The BuildingRegulations of England and Wales .
- ApprovedDocument P : Electrical Safety - Dwellings’. ( P1)

Scope ofPart - P .
Part - Papplies to electrical-installations in buildings or part of buildingscomprising .
i) Dwellings houses and Flats .
ii) Dwellings and business premises that have acommon [ Metered-supply ] Etc.

Re-cap: The scope of the Electricity at WorkRegulations 1989 . is much wider than [ BS-7671:2008:2011: ] taken from Extracts . BS - p.10. 2008
Requirementsfor Electrical-Installations in that they require .

- Installationsto be constructed so as to be safe - Regulations 4(1) 5.6.7.8.9.10.11.12.
- Installationsto be maintained so as to be safe - Regulation 4(2) .
- Associatedwork to be carried out safely - Regulation - 4(3) 13.14.15.
- Workequipment provided to be suitably for the purpose - Regulation 4(4)
- Personsto be [ competent ] -Regulation - 16 .










 
Certification and Reporting.

Point to note- During incident investigations the ( HSE ) may examine .Electrical-installation-condition-report . any Certificate . Report .

( EIC) . ( EICR ) . ( MWC ) . Schedule of inspections . Schedule of test-results .

 
Question - aFinal-circuit is the wiring between the ? -&-s

Definitions - p.28 . Answer .
Circuit connecteddirectly to current-using-equipment . or to a socket-outlet or socket-outlets or other-outlets-points for theconnection of such equipment .

Definitions - p.34 .
Ring-final-circuit - Final-circuit arranged in the form of a ring and connected to a single-pointof supply . [ Consumer-unit and the current-using-equipment ]


 
If I have the C&G - 2392 will I have totake the new C&G - 2394 .
No ) The 2392 will remain the standard for .Inspecting & Testing your own work to sign it off under . Part-P of the Building regulations .

2394 : Devices for protection against the risk of fire includes .

RCDs not exceeding 500mA .
RCDs not exceeding 300mA .
Time - delayed RCDs .
Type - B circuit-breaker .

The regulations have to state the facts .

p.139 . 532 : Devices for protection againstthe risk of fire .

532.1. Where in accordance with the requirements of regulation - 422.3.9. it is necessary to limit the consequence of fault-currents in awiring-system from the point of view of fire-risk . the circuit shall be either:

i) protected by an RCD complying with regulation - 531.2. for fault-protection .

- the RCD shall be installed at the origin of the circuit to be protected.
- theRCD shall switch all . live-conductors’ .
- the rated-residual-operating-current of the RCDshall not exceed 300mA .



 
Q) . To comply with Part - 6 of BS-7671:2011: Periodic inspection & testing shall be specifically undertaken by . ?
Part - 6 . 621.5. p.195 . A). Periodic inspection & testing shall be undertaken by a [ competent-person ] -&-s

Blast from the past .
Q) . An electrical-installation has thefollowing single-phase-circuits installed. using multi-core-thermoplastic . non-armored-cables.
2 x 6A - lighting . = 4
2 x 32A - ring-final-circuit . = 8
1 x 16A - water-heater . = 2
1 x 32A - cooker . = 2

If the circuits are contained within . PVC - trunking prior to entering the consumer-control-unit - ( CCU ) Q) . how many Live-conductors’ would be present in thetrunking . [ 6 . 8 . 16 . 24 . ] A) Part- 2 . Definitions - 30 . Live-part .

Live-part . A conductor or conductive-part intended to be energized in normal-use . including a Neutral - conductor.

 
Based on the syllabus ofthe . -&-s 2394 :Initial-verification exam . designed around - GN-3 . & BS-7671:2008:2011: is your . 2394 - syllabus .

Gentle - reminder . Chief-examiners-report - 2012 .
It would appear that candidates are not awarethat a ( Working-knowledge of Guidance-note 3 . &BS-7671:2008:2011: ) is required to achieve success in thisqualification . candidates demonstrated ( gaps ) in both Technical and Underpinning of subject matters . Based

My point:- Candidates wishing to take the 2394 or 2395 : Qualifications would be strongly advised to obtain the 17[SUP]th[/SUP] Editionfirst . Which demonstrates a knowledge and understanding ofthe 17[SUP]th[/SUP] Edition - 2011:

The 2394 or 2395 : Qualifications is intended to enable candidates to develop thenecessary-understanding and technical-knowledgerelating to the . Inspection . Testing and Certification of electrical-installations . ( BS-7671:2008:2011: and Guidance-Note 3 )
 
It would appear that candidates are notaware that a ( Working-knowledge of Guidance-Note - 3 . & BS-7671:2008:2011: ) is required to achieve success in thisqualification . candidates demonstrated gaps in both technical and underpinningof subject-matter .

BS-EN-61008-1 . shoulddisconnect in ( 200mS ) at 1 xIn . ( Wrong-Answer )
½ -In no-trip
100% - In / 300mS .
500% - In / 40mS .

BS-200mS
BS-EN - 300mS . Watch thewording .

GN-3. p.59 . Table- 2.9 .Operational-tripping-times for various RCDs
 

Usingof correct - terminology : Chief -Examiners report . 2012 .

Correct- terminology must be used when answering questions . candidates continue touse ( Incorrect - terminology )
Incorrect- titles of documents continue to appear in candidates “ responses “ some candidates are still using 16[SUP]th[/SUP] - Edition/ terminology .

►► Candidates are expected to Use terms from BS-7671: from the 17[SUP]th[/SUP] Edition - 2008: first -amendment - 2011:

Main-equipotential-bonding-conductor. 16[SUP]th[/SUP] - Edition O.S.G. 2004 . some candidates are still using 16[SUP]th[/SUP] - Edition/ terminology / 2012:

p.27 . Protective-bonding-conductor: Protective-conductor provided for the protective- equipotential-bonding . 2008:
p.27 . Protective-equipotential-bonding: Equipotential-bonding for the purpose of safety . 2008:

“Reason “ p.24 .

Equipotential-bonding. Electrical connection maintaining various - exposed-conductive-pars andextraneous-conductive-parts . at substantially the same potential - ( See also Protective-equipotential-bonding)

p.32 . Protective-bonding-conductor: Protective-conductor provided for the protective- equipotential-bonding . 2011:
p.32 . Protective-equipotential-bonding: Equipotential-bonding for the purpose of safety . 2011:

“Reason “ p.27.

Equipotential-bonding. Electrical connection maintaining various - exposed-conductive-pars andextraneous-conductive-parts . at substantially the same potential - ( See also Protective-equipotential-bonding) 2011:

Descriptionsof Instruments used for particular-testscontinue to be ( Vague ) in order to be fair to all . candidates onlythe title of instrument(s) stated in Chapter - 4 of Guidance-Note 3 are (Acceptable ) . the instrument used for the measurement of - ( PFC ) prospective-fault-current . is ( Not - identified ) by name in GN-3 but a -Title of ( PFC- tester would be acceptable )

Itwould appear that candidates are not aware that a working knowledge of Guidance-Note 3 .and BS-7671:2008:2011: is required to achieve success in this qualification .candidates demonstrated gaps in both technical and underpinning of subjectmatter .
 
Gentle - reminder .
It would appear that candidates are notaware that a ( Working-knowledge of Guidance-Note - 3 . & BS-7671:2008:2011: ) is required to achieve success in thisqualification .

Gentle - reminder .
It would appear that candidates are notaware that a ( Working-knowledge of Guidance-Note - 3 . & BS-7671:2008:2011: ) is required to achieve success
in this qualification . candidatesdemonstrated gaps in both technical and underpinning of subject-matter .

Back to basics .
16[SUP]th[/SUP] Edition - BS-EN-61008-1 . 1995 . General-rules . ( ReplacesBS-4293 ) 1983 . which remains-current .
16[SUP]th[/SUP] Edition - BS-4293 : 1983 - ( 1993 )Specification for residual-current-operated-circuit-breakers . ( Replacedby BS-EN-61008-1 )

P.286 . BS-7671:2008:2011:
BS-EN-61008-1 . 2004 +12:2009 . residual-current-operated-circuit-breakers - ( without-integral-overcurrent-protection) for household and similar uses - ( RCCBs ) General-rules .
 
C&G -2394 . and C&G - 2395 . splits the previous- 2391 down the middle .

2394: Initial-verification-qualification . Inspection& Testing . New-installation(s)
2395 : Periodic-inspection-qualification . Inspection & Testing . Existing-installation(s)

C&G - 2394. exam forms part of what was previously known as the 2391-10 . The qualificationhas been split into-two-routes .

Gentle - reminder .
It would appearthat candidates are not aware that a (Working-knowledge of Guidance-Note- 3 . & BS-7671:2008:2011: ) is required toachieve success in this qualification .

Appendix - 1 - Normative . p.277 . ( Where did I go wrong with . my Q/As . BS- .BS-EN ) RCDs
Note : CertainBritish-Standards . have been withdrawn since the issue of the - 16[SUP]th[/SUP] Edition in 2001 . from the dateof withdrawal . certificates and marks already awarded may continue to apply to. production until a date-specified in the - superseding-standard . Etc .

Characteristicsof RCDs . Basics .
RCDs aredefined by a series of electrical-characteristics. three-main-characteristics are :
i) . Therating of the device in amperes ( I )
ii) . The rated-residual-operating-current of the protective-device in - amperes . IΔn

iii) . Whether the device operates ??
- Instantaneously. - ( G )
- Incorporatesan . international-time-delay - 2394: To permit discrimination . (S )

p.26. Discrimination - Ability of a protective-device tooperate in preference to another . protective-device in series .
 
Items : need to be addressed when providing-switchingoff for ( Mechanical-maintenance ) of an extractor-fan .

Purpose ofswitching off for - ( Mechanical-maintenance )
The purposeof switching off an ( Extractor-fan for Mechanical-maintenance) is to provide-protection for a person-engaged in carrying out . (Mechanical-maintenance ) that may otherwise involve the risk of physical-injury . such as burns . or injury from . ( Mechanical-movement ) such as from arotating-fan-blade . - Regulation /537.3.1.1. refer

Switching devicepositioning or marking :
eachdevice for switching of an - ( Extractor-fan for Mechanical-maintenance ) is tobe durably-marked . and located so as to be readily-identifiable and convenient. for the intended use . - Regulation / 537.3.2.4.

example of awall-mounted-extractor-fan-switching-device . note :- this device is notsuitable for - installation where unintentional-reactivation of equipment may occur .

Unintentional-reactivationof equipment :
the meansfor switching off an extractor-fan for ( Mechanical-maintenance ) shouldpreferably be positioned where it will be . continuously under the control ofthe person-working of the fan . However , where this is not practicable .suitable-provision must be made so that precautions can be taken to prevent .any electrically-powered-equipment frombeing unintentionally-reactivated-during-the ( Mechanical-maintenance ) Regulation/ 537.3.1.2.
refer. such a provision is for the switch tobe provided with a device that . enables the extractor-fan-switching-device to be padlocked in the disconnected-position . with theswitching-device-locked-off and thekey-under-the control of the person-carrying out the ( Mechanical-maintenance ) inadvertent and unauthorized-operation of theswitching-device is prevented - Regulation / 537.3.1.2. refers .

Indicationof switching-position :
The Open-position of the contacts of a device for switching offfor . ( Mechanical-maintenance ) must be visible . or the OFF or OPEN-position must be clearly and reliably-indicated - Regulation /537.3.2.2. refers . Indication of that position must occur only when the (OFF or OPEN-position ) on each-pole hasbeen fully-attained . an indicator-light will not meet the requirements . forindication . positive - ( Mechanical-indication ) such as the position of anoperating-handle is required .

Switching ofan extractor fan with a - run-on-timer-connected toa lighting-circuit :
Control ofan extractor-fan with . run-on-timer-connected to a lighting-circuit . is often-provided for a toilet or bathroom . so that the fan-continues to run for a .predetermined-period after the light isswitched-OFF . in such an arrangement . the fan is functionally-operated by the ( Light-switch ) so as to allowthe automatic-fan-run-on-operation .

Fan-isolator-switch- ON / OFF indicator . pull-cord-type
Question 2394: does a Light-pull-cord show us indication . when OFF or ON. Question- is the lamp blown . ?? what indication do we have .

Fan-isolator-switch -Three-pole with padlock . surface-mounted .
3 - pole-fan-isolator-ceiling-pull-cord-switch .

Has thebathroom got a window ??? . it is a 100% - requirement if there is No-Window .

( Fan-isolator-switch- ON / OFF indicator . pull-cord-type )
( Fan-isolator-switch - Three-pole with padlock . surface-mounted ) mustbe positioned outside of the room-containing-the-shower.

Example : Shower -extractor-fan . this has been specifically-designed for the use in a . shower and it also incorporates a halogen-lamp which is 12V .
Fans like this require-additional-wiring as both a . permanent-live . and switched-live . are required as the fan has a built-in-timer .so that it continues to extract-air fora set-period of time . after the light in the room has been switched-OFF .

These fans are wiredfrom the existing-light in theshower-area and go via a three-pole-switch to the fanitself . when you operate the shower-room-light the fan switches on automatically and switches OFF . after a set period-time .

( three-pole-switchto the fan itself ) allLive-conductors can be isolated . when needed .

- Switched-live : it becomes live when the switch is ON .
- Permanent-live : this is live all the time .

Old-colours - Fan-isolator . 3-core & earth .
Switched live ( it becomes live whenthe switch is on ) “ Yellow “ L1 / SL ( Sleeved - Red )
Permanent live (this is live all the time) “ Red “ L2 / L
Neutral → Blue .

Harmonised-colours :
Switched live ( it becomes live when the switch is on ) “ Black “ L1 / SL
Permanent live (this is live all the time) “ Brown “ L2 / L
Neutral Gray - sleeved Blue .




 
Gentle - reminder . Chief-examiners-report - 2012 .
It would appear thatcandidates are not aware that a ( Working-knowledge of Guidance-note-3 . & BS-7671:2008:2011: ) is required to achieve success in this qualification . candidates demonstrated ( gaps) in both Technical and Underpinning of subject matters . Based




- - - Updated - - -

RCD -Testing :
Testingthe ( Trip - times of RCDs ) with all commonly found RCD - current-ratings .
For most -International-applications & the UK . 5 test(s) must be - performed .

1) - (1/2) x RCD - current-rating . to ensure theRCD does not trip when ( Half ) the rated-current is following in the RCD .
100% . 2) - 1 x RCD -current-rating . This is a trip-test to ensure the . RCD - trips with the specified-trip-time .
500% . 3) - 5 x RCD -current-rating . A trip-test to ensure theRCD - trips within the specified-time .
4 & 5) both the ( 1 x and 5 x tests ) must bepreformed at both - ( -&-s 0° degrees and 180° degrees . positive and negative-supply-half-cycles . to ensure ( Worst-case-time is recorded)

Theauto - RCD test : allows all the above tests to be preformed - Automaticallywhilst the operator . stands by the RCD and resets it as it Trips . results can then be recalled tothe screen .
 
Functional-Testing- 612.13.1.
Whichstates that for an RCD ( Theeffectiveness of any test-facility incorporated in the device shall be Verified)

Re-cap :Built-in-test-button . RCDs
test-button- can be used to place a load between the output - Line-conductor and theinput-neutral-conductor . creating animbalance in the windings . this imbalance causes the RCD to trip .

point to note : thetest-button only demonstrates that the trip-mechanism-works . confirming-nothing-else .about it’s specific-operational- characteristics .
 
Re-cap -2394: with 2008: & 2011:
17[SUP]th[/SUP]Edition increases the need for circuit(s) to be provided with RCD-protection -The circuit(s) that require RCD are as follows .

i) . Where the - Earth-fault-loop-impedance . isto high to provide the required-disconnection-times . where thedistributor - ( DNO ) or does notprovide an Earth - TT - system(s) 411.5.
ii) . Socket-outlet - circuit(s) in domestic andsimilar-installation(s) - 411.3.3.
iii) . For circuit(s) of locations-containing-a bathor shower - 701.411.3.3.
iv) . For circuit(s) supplying mobile-equipment .not exceeding - 32A for use outdoors - 411.3.3.
v) . For cables without earthed-metallic-coveringinstalled in walls or partitions at a depth of less than 50mm and not protectedby earthed-steel-conduit or similar - 522.6.7.
vi) . Forcables without earthed-metallic-covering installed in walls or partitions withmetal-parts - excluding screws or nails . and not protected byearthed-steel-conduct or the like - 522.6.8.

for items( ii and vi ) above the RCDs used shouldbe rated at 30mA .
 
(Additional-Protection Only ) 5 x 30 =150mA
RCDs are rated at . 30mA and 40mS . andmust disconnect the supply within ( 40mS ) for a leakage-current of ( 5 x times) the rated-operating-current - 150mA . refer to BS-7671:2008:2011: - 415.1.1.
 
Re-cap . What the Regulations arereminding us . p.29 / p.36 .

Inspection :-Examination of an electrical-installation using all the ( Senses as appropriate )

Testing :- Implementation of ( measures to assess ) an electrical-installation by means of which its . ( effectiveness is proved ) this includesascertaining-values by means of ( appropriate-measuring-instrument(s) it has been -Defined . Part - 4 . 2 . 3 . 5 . 6 . refer to . GN-3 .

Verification :- All ( measures by means ) ofwhich compliance of the electrical-installation with the relevant-requirementsof - BS-7671 : are checked . comprising . Inspection . Testing and Certification .
 
BS-7671:2011: BS-EN-61557 : P.288 .
BS-EN-61557: Electrical-safety in low voltage distribution systems up to 1000V a.c and 1500V d.c. - Equipment for testing . measuring ormonitoring of protective-measures . ( General-requirements ) 612.1. - 621.3.

P.190 - BS-7671:2011: 612.1.

Testing :
The tests of . Regulations - 612.2. to 13 . where relevant . shall becarried out and the results compared with relevant-criteria .

P.194 - 621.3.
Periodic-inspectionand Testing :
Precautionsshall be taken to ( Ensure ) that the periodic-inspection and testing shall not cause ( Danger ) to persons or livestock . and shall not cause damage to property and equipment even if the circuit is defective . Measuring-instrumentsand monitoring-equipment and methods shall be chosen in accordance withrelevant-parts of ( BS-EN-61557 ) ifother measuring-equipmentis used . it shall provide no less degree ofperformance and safety .

BS-EN-61557-2 :Insulation-résistance .

p.288 . BS-EN-61557-6 : 1998 .Residual-current-devices - ( RCD ) in TT . TN - 612.8.1 . a) 2)
p.193 : General .
The - Verification . ofthe effectiveness of the measures for . fault-protection byautomatic-disconnection of supply is effected as follows . a) 2)
a) TN - system . Compliance with .Regulation - 411.4. shall be verified by . (2)
verification of the -characteristics and / or effectiveness of the associated-protective-device .This verification shall be made :

- for -Overcurrent-protective-devices . by ( Visual-inspection ) i.e. short-time or instantaneous-trippingsettings for circuit-breakers . current-rated and type for fuses .
- for - RCDs . by ( Visual-inspection & Test ) The effectiveness of disconnection ofsupply by RCDs . shall be verified using ( Suitable-test-equipment according to BS-EN-61557-6 . ( Part - 6 ) Regulation - 612.1. to confirm that therelevant-requirements in . Chapter - 41 are met .

Testing :
The tests of . Regulations - 612.1. where relevant . shall be carried outand the results compared with relevant-criteria .

The disconnection-timesrequired by . Chapter - 41 shall be verified . Chapter - 41 . Protection againstelectric-shock .

Safety -LVD .

BS-EN-61557: Electrical-safety in low voltage distribution systems up to 1000V a.c and 1500V d.c. - Equipment for testing . measuring ormonitoring of protective-measures . ( General-requirements )

Part - 1 :General-requirements .
Part - 2 : Insulation-résistance-testers .
Part - 3 : Loop-résistance .
Part - 4 : Low-résistance-ohmmeters .
Part - 6 : Residual-current-devices - RCDs . in TT and TN- system(s)
Part - 7Phase-sequence .

Other reference standards for testing - RCDs .
RCD -Standards : BS-EN-61008-1 . BS-EN-61009-1

BS-EN-61008-1 : ( Part - 1 )
Residual-current-operated-circuit-breaker - ( Without ) integral-overcurrent-protection . for household andsimilar uses. ( General-rules )
BS-EN-61009-1 : ( Part - 1 )
Residual-current-operated-circuit-breaker - ( With ) integral-overcurrent-protection . for household andsimilar uses. ( General-rules )

Current-multiplier ( x ) x 1 / 100%.
Current-multiplier ( x ) x 5 / 500%.

Megger -1552 . Do we get lazy withMultifunctional instrument(s) .
Two-settings.
Automatic: - Nulling-out . “ Leads
Manual : By calculation . Subtracting . “ Leads

RCD - ( G ) ~ 30mA . ( BS-EN )

For thesake off . -&-s . Select the -RCD-function using thefunction-selector-switch . Am using theword - Manual - Setting(s) : back to basics

( 1/2 . 0.5 ) Half of 30mA / 15mA .
- Start ofTest : with ( IΔn ) 0° .step 1 . RCD should not Trip .
- Start ofTest : with ( IΔn ) 180° .step 2 . RCD should not Trip .

(500% . x5 )
- Start ofTest : with ( 5 x IΔn ) 0° .step 3 . RCD should Trip-out . ( Example - 0° / 7.7mS … 180° / 11.1mS ) Manual .
Re-activateRCD . - Start of Test : with ( 5 x IΔn ) 180° .step 4 . RCD should Trip-out .

(100% . x1 )
- Start ofTest : with ( 1 x IΔn ) 0° .step 5 . RCD should Trip-out . ( Example - 0° / 46.0mS … 180° / 35.7mS ) Manual .
Re-activateRCD . - Start of Test : with ( 1 x IΔn ) 180° .step 6 . RCD should Trip-out .

Highest of the two-readingsshould be recorded - Certificate
 
Re-cap. Table- 3A / p.295 . BS-EN-61008-1 : & BS-EN-61009-1 :
Delay ( S ) Trip-time (mS ) Minimum & Maximum . tΔ .. 130mS < tΔ < 500mS .

Table -41.5 gives maximum-values of ( Zs ) for non-time-delayed - RCDs .
 
Value ofthe two-current-tests ??? ( Example - 0° ~ / 46.0mS … 180° ~ / 35.7mS )
 
2394: Guessworkdoes not pay .

Point to Note : it appears thatmany candidates believe the . Minimum-acceptable-value forinsulation-résistance is ( 2M and not1M ) stated in BS-7671:2008:2011:

Re-cap. Table - 61 . MINIMUM-value of insulation-résistance . Wording is MINIMUM . ( 1MΩ ) BS-7671:2008:2011:
Note - 2: Insulation-résistance-value(s) are usually-higher than those of Table-61 . ◄◄◄◄◄

 
Point toNote : - Exams 2394 : There is no excuse for studying for any exams. Q/As are taken from . BS-7671:2008:2011: - GN-3 .

Point to Note : “ a Must “ GN-3 . P.58 . :mad2:
Operationof residual-current-devices . ← ← ← ← ← ← .
411.4.5. - For each of the tests . readings should betaken on ( Both-positive and negative-half-cycles ) ( 0° & 180° ) andthe longer-operating-time-recorded .

Technical-Knowledge; Examiners - 2012 .

Many-candidateswere unable to correctly -indentify the requirements for the application ofRCDs . the Maximum-test-currents appliedand the Maximum-operating-times . many candidates failed to score as well asthey may as they failed to indentify the test-currents . in mA . to be appliedat each step of the test . failed to indentify the correct-operating-times ateach step and not indentifying that the ( Highest of the values at 0° and 180° ) should be recorded . Many candidatesfailed to confirm the operation of the ( Test-button ) on completion of the electrical-tests. Somecandidates stated incorrectly that an RCD to - BS-EN-61008-1 should disconnectin ( 200mS ) whentested at 5 x IΔn .
 
Regulationshave to state the facts : p.167

Facts : Minimum-cross-sectional-area of the . main-protective-bonding-conductor .in relation to the ( Neutral of the supply )

Electrical-installation-condition-reports. & “ Testing “

Gas &Water-installation-pipe(s) The size of main-protective-bonding-conductor is always selectedfor the appropriate tables in the regulations . 54.8.
( 10.0mm[SUP]2[/SUP] ) is fine for most installations of a C.S.A.of the supply-neutral-conductor ( table- 54.8. - 35mm[SUP]2[/SUP] or less 10.0mm[SUP]2[/SUP] )

The conductorsare connected in a appropriate-place forboth the Gas - Water-installation-pipe(s) using BS-951 - clamps . and also suitable indentifiedwith the correct-label . - Provision of earthing and bonding-labels at all appropriate-locations

Older-installation(s) where the installation has - supplementary-bonding they will also have to bechecked . - Provision of earthing and bonding-labels at allappropriate-locations

 
Verifying( Zs ) readings . ( Lighting-circuit )
Determine ( Zs ) adding ( Ze ) which you determined during the prospective-earth-fault-current-test. to your value of ( R[SUP]1[/SUP] + R[SUP]2[/SUP] ) looking attable - 41.3. Maximum - ( Zs is 6A - 7.67Ω ) for a 6A circuit-breaker to operate . your ( Zs ) is well below this . it is important to remember that theregulations do require a adjustment to the figure to allow for the increase ofrésistance of conductors of increase oftemperature when a circuit is under-load .

You canfind guidance on this - Appendix - 14 . p.424. 80% method . so the tabulated - (Zs ) needs to be reduced to 80% - per-cent of its value you can just do this multiplying . ( 7.67 x 0.8 = 6.14 )
 
Used as a Leaning-curve .

High-current-loop-testing :
For Supplies that are ( Not RCD - protected ) thehigh-current-test . can be used . as there is no-risk of tripping and RCD .

Megger - LTW-325 : Loop-impedance-tester .
Two-wires -loop-impedance-measurement

Line to earth - testing.
Line toneutral - testing .
Prospective-short-circuit-current-test. ( PSCC )

The ideaof this test is to measure the maximum-current that can flow betweenlive-conductor(s) in the event of a fault .
The reasonthat we have to know this to make sure that we select the right type ofprotective-device . where it is installed in the circuit .it needs to carry thehighest amount of current without damage . Megger - LTW-325 . Loop / No-trip . Loop / Max-Z

Firstly :we must have Safe-Isolation . locking - OFF . Padlock
Danger -400 Volts .
Warning -This is a Live-test .

Green-lead- onto the neutral .
Loop / Max - Z. Loop - high-current .
Testbetween the neutral which is a live-conductor - then test between the incoming- line-conductor . PFC - ( 2241A ) which is 2.24kA .
Need to dothe same test between all three-line-conductors . ( L1 . L2 . L3 )

Brown - L1 - 2241kA . 2.24kA .
Black- L2 - 2256kA . 2.25kA
Gray - L3 - 2257kA . 2.25kA

We can seethat the reads 2.25kA .
becausethis is a Three-phase supply . you need to double the valve I’ve got . 2.25 x2 is 4.5 . ( 4.5kA is what you write onyour test - certificate )

Megger - LTW-325 : Loop-impedance-tester .
External-earth-loop-impedance-test- ( Ze ) Earth-fault-loop-impedance-test-instrument .

Firstly :We must have Safe-Isolation . locking - OFF . Padlock
Danger -400 Volts .
Warning -This is a Live-test .

Disconnectedthe - Earthing-conductor . ( Which is aProtective-conductor )
Reason forthis . We do not want ( Parallel - paths ) we need to know the résistance between hereand the supply-transformer .

With leadsto GS-38 .
Green-lead with a crocodile-clip .
Red - lead. with plastic-cover with maximum cover . 2mm . ( Live-parts )
Loop /High-current .
Loop / Max - Z.

Connectthe Green-lead with a crocodile-clip . To the disconnected - Earthing-conductor .
With theRed-lead . with plastic-cover with maximum cover . 2mm . ( Live-parts )

Brown - L1 - incoming Line to earth . value of 0.17. you’ll need to know the highest-value . you’ll testbetween all three-lines .
Black- L2 - 0.17
Gray - L3 - 0.17Ω . thereall consistent . so your value is - 0.17Ω .
 
Ring-final-circuit-test.

Firstly :We must have Safe-Isolation . locking - OFF .
3 - thingsneeded . Lock-off that is appropriate forthe type off isolation . Padlock for locking-off . Sign - danger-do-not-switch-on.
Danger -400 Volts .
Warning -This is a Live-test .

Wheninsolating any-mains . ask permission . is it safe to do so .
Lock -off . placing the lock-off . padlock . cable-tie the Sign onto the padlock - danger-do-not-switch-on . You are the key-holder .

Is it Dead - With a approved-voltage-indicator
Test between. Earth to Line .
Testbetween . Earth and Neutral .
Testbetween . Neutral and Line .

With aknown device - proving-unit . With aapproved-voltage-indicator - all lightsare working .
Back to. With a approved-voltage-indicator . Test between . Earth and Line .

Ring-final-circuit-test- with all the cables disconnected .
Instrument-use. Low-résistance-ohm-meter . turn it on. and Null the leads . Re-cap . you leads have résistance 0.04 in them . which you do not want toinclude in your test . Zero the Leads .

Test each-conductor. End-to-end . ( Single-cables arethe same-size 2.5mm[SUP]2 [/SUP] ) not T&E .
Line-conductor(s) - 0.56 .
Neutral-conductor(s) - 0.55
Circuit-protective-conductor(s) - 0.57

Next :- Cross-connect the . Line and neutral-conductor - Connector-block .
Next :- Cross-connect the . Neutral and Line-conductor - Connector-block .

Dead /Testing . - your probes are 4mm . Not a Live-test . test between the two-ends off theconnector / blocks . ( Loop ) 0.27 you should be getting half the reading of one of these conductors . go toeach-socket-outlet . & test between each Line and Neutral at each socket .
You are .checking that it is a Ring. And no interconnections . from a socket-out-let - Line/ Neutral - 0.31 . ( Plus - Polarity) by continuity - method

You havecheck the . Line and Neutral at each-socket=outlet .
You doingthe same test . between the Line and Earth . & at each-socket-outlet .

Next :- Cross-connect the . Line(s) and Earth(s) - Connector-block . 0.27 . all you socket-outlets have beentested . your at the last-one - reading between .05 & the originalreading of 0.27 . - your reading is 0.29
 

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