Re-take - Useful Information for 2394 :

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BS-7671:2011; & GN-3 . wouldany of this come up on Exams . ( Everytest has it’s Merits ) :icon_bs:

C&Gs / GN-3,Stipulates that, The installation must remain isolatedfrom the ( Supply ) until alltesting has been completed & the earth-electrode connection-reinstated .
C&Gs / GN-3,Stipulates that, This disconnection will ensure that thetest-current Only passes through the, earth-electrode and not through any ( Parallel-paths )

( Where-required )
Re-cap : 612.7. Earth-electrode-résistance.
BS-7671: Stipulatesthat where, earth-electrodes are usedthey should be tested. BS-7671: Electrode-resistance to Earth shall be measured
If the electrode under test forms part of the earth-return for a TT – system in conjunction with an RCD, GN-3 describes the following method(s) .

• Disconnect theinstallation-protective-equipotential-bonding ( equipotential / equal bonding ) from the earth-electrode to ensurethat the test current passes only through the earth-electrode .
• Switch off the consumer’s unit to isolate theinstallation
• Using a Earth-loop-impedance-tester, testbetween the incoming line-conductor and the earth-electrode . BS-EN-61557-3 Instruments conforming .
• Reconnect : theprotective-bonding-conductor(s) when the test is completed .

Record the results on a, Schedule of test-results , accordingto Appendix - 6 , BS-7671:
GN-3 : stipulates that, that an acceptable value for the measurement of the earth-electrode-résistance, would be less that 200Ω .
BS-7671:2011: P/57 . Table 41.5 . Note – 2 *: The résistance of the installationearth-electrode should be as low as practicable. A value exceeding 200Ω may not be stable. Refer toregulation 542.2.4. The type & embedded depth of an earth-electrode . Etc

Supply Connected .
Testing earth-fault-loop-impedance :

Your object of this test is to ( Verify) that the impedance of the whole ( earth-fault-current-loop ) islow enough to allow the overcurrent-protective-device to operate within the disconnection timerequired Stated in BS-7671:2011: in our case here Table 41.3. RCBO / Circuit-breakers .

P/36 . Verification : All measures by means of which compliance of the electrical-installationwith the relevant requirements of BS-7671:are checked .
Comprising . Inspection , Testing & Certification .

“ Competent-person “

612.9. Earth-fault-loop-impedance . ( 2392-10 , Circuit-loop-impedance )
Where protective-measuresare used, which require knowledge of earth-fault-loop-impedance, the relevant-impedancesshall be measured .

GN-3 . Re-cap . Protection by automatic-disconnection of supply . P/51.
The effectiveness of measures for fault-protectionby ( ADS ) can be verified for installation(s) with a TN – system by :

• Measurement of earth-fault-loop-impedance .
2392-10 , Reason :- youhave confirmed that you have an Earth before testing your RCDs / RCBOs
• Confirmation by visual-inspection that , overcurrent-device have suitableshort-time or instantaneous tripping setting forcircuit-breakers,
• where RCDs are employed, testing to confirm that thedisconnection-times of Chapter 41 . of BS-7671:can be met .

RCDs :- Residual - dual / Line & Neutral-conductor(s) Two / dual in Balance :rant:

 

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( T ) . One of the most important regulations - 632.4. P/196 . Defects or omissions
Revealed during inspection & testing of the installationwork covered by the Certificate shall be made good before the Certificate isissued . :icon_bs:

Periodic Inspection ( Electrical-installation-condition-report ) EICR .

P/195 . 621.3. Precautions shall be taken to ensure that the periodic-inspection &testing shall not cause danger to persons or livestock & shall not causedamage to property and equipment even ( if the circuitis defective )

• Measuring-instruments & Monitoring-equipment and methods shall bechosen in accordance with relevant-parts of BS-EN-61557. If other measuring-equipment is used, itshall provide no less degree of performance & safety .

Measuring-instruments& monitoring equipment and methods shall be chosen in accordance withrelevant-parts of BS-7671:2011: plus –GN-3

P/195 . 621.4. Theextent and results of the periodic-inspection & testing of an installation,or any part of an installation, ( shallbe recorded )

P/195 . 621.5.Periodic-inspection & testing shall be undertaken by a , Competent-person.

631.2. Upon completion of the periodic-inspection& testing of an ( Existing-installation) an Electrical-installation-condition-report , based on the model given inAppendix – 6, shall be provided .

- such documentation shall include details of the extent of the installation& limitations of the inspection & testing covered by the Report . together with records of inspection, theresults of testing and a recommendation for the interval until the , next periodic-inspection .

P/196 . 634.1. Following the periodic-inspection& testing described in Chapter -62.
An Electrical-installation-condition-report,together with schedules of inspection& schedules of test-results, shall be given by the person carrying out theinspection, or a person authorized to act on their behalf, to the personordering the inspection. Etc . refer to.

P/196. 634.2. Any damage, deterioration, defects,dangerous-conditions and non-compliance with the requirements of theregulations, which may give rise to danger, together with any significant-limitations of theinspection and testing, including their reasons, shall be recorded .

 

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2392-10 : Circuit-breaker(s) - circuit-protection .
Tripping-characteristics & therefore circuit-protection are set by the installer.

 

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2392-10 . Installing : Overcurrent-protective-device(s)

Fault-protection .P/53.
411.3.2.2. Overcurrent-protection-device , providingcircuits Not exceeding 32A . Shall havea disconnection-time not exceeding , 0.4s . Table 41.1

 

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2392-10 : basics .

Testing for Continuityof protective-conductor(s) 612.2.1.

to ensure that thecircuit-protective-conductors, ( CPCs ) is correctly connected, as the Regulation specifies . when testinghas a total-résistance which is low-enoughto permit the overcurrent-protective-device to operate . with the disconnection time requirements of Regulation - 411.4.5.

Earth-fault occur . RCDs for additional-protection

 

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2392-10 / 2394. :icon_bs:

134: Erection & Initial-verification of electrical-installation(s)

134.2.1. P/22. Initial-verification .

During erection and oncompletion of an Installation or an Additionor Alteration to an installation & before it is put into service

Appropriate , Inspection & Testing shall be carried out by Competent-person , to verify that the requirements of this standard have been met . ( & Appropriatecertification to be issued )

135. Periodic Inspection & Testing . ( Recommendation for subsequent periodic-inspection & testing required)
135.1. it is recommended that ( Every electrical-installation ) is subjectedto periodic-inspection & testing, Etc

Dealing with : P/21.
134.1.1. Good workmanship & proper-materials .
134.1.2. Characteristics of equipment not to be impaired during erection of Installation(s)
( T ) 124.1.3. Conductor(s) to be identified . ( Polarity)
134.1.4. Every electrical-joint and connection shall beof proper, construction as regards conductance, insulation, mechanical-strengthand protection
134.1.5. Electrical-equipment shall be installed insuch a manner that the ( design-temperatures not to be exceeded )
134.1.7. Suitable-warning-signs & / or notices tobe provided where necessary for safety-purposes.

2392-10 : For :- Electrical-equipment to be installedin accordance with the ( Instructions provided by the manufacture )
134.1.2. Require that equipment must Not be impaired by the ( Installation-process )

Re-cap : P/33.
Reporting :Communicating the results of,periodic-inspection & testing , of an electrical-installation , to theperson ordering the work .

2392/10 : Skilled-person. P/34
A person with , technical-knowledge or sufficient-experience to enable him / her to avoid dangers , which electricity may-create .

Verification: P/36.
All measures by meansof which compliance of the electrical-installation with the relevantrequirements of BS-7671: are checked ,
Comprising , Inspection, Testing & Certification . Etc

Appendix 15 ( Informative ) P/425.
2392-10 : Regulation - 433.1.103.

The Regulation(s) havestated the facts . :vanish:
The load-current in anypart of the circuit should be unlikely to exceed for long-periods the ,current-carrying-capacity of the cable .
Re-cap . 433.1.103.refers , Thiscan generally be achieved by:
i) locating-socket-outlets to provide reasonable sharing of the loadaround the ( Ring )
ii) Not-supplying,immersion-heater(s) , loads of asimilar-profile from the , ring-circuit.
iv) taking-account of the total-floor area being served , ( Historically , a limitof 100m[SUP]2 [/SUP] has been adopted )

iii) connecting-cookers, ovens and hobs with a ( rated-power-exceeding 2kW) ontheir own-dedicated radial-circuit .

 

[Robert Wesson]

made a mock test if it helps 2394


[url]http://2394.robertwesson.co.uk/



[/URL]

 

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Robert Wesson , anything to help Electricians . most appreciated . Amber . :icon14:

 

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This is Notcriticism just some Facts.

If we take the time to Open any Books , It’s right in front of Us . Yeah. :icon_bs:

GN-3 Inspection & Testing.

is an essentialguide and leading reference manual on this important subject. The Guide has beenrevised to align with the BS-7671 (------ Wiring Regulations) 17[SUP]th[/SUP]-Edition-Amendment No 1, the National - Standard to which all domestic and industrialwiring Must -Conform.

Contents : Initial-verification, Periodic-inspection& testing, Test-instruments and forms.

Polarity-Testing . GN-3.. P/47
612.6. The polarityof all circuits must be verified beforeconnection to the ( Supply ) with either an ( Ohmmeter or the continuity-range of an Insulation & Continuity-tester)

As GN-3 have stated the Facts . Instrument: Use a low-resistance-ohmmeter, forthese-test. Etc:
As the Wording means : Guidance-Only

As GN-3.. reminds Us , Alternatively, polarity can be verified byvisually checking ( Core-colours at terminations ) thus verifying the installer’s connection(s) this will come up in Exams .

2392-10 / 2394 . As GN-3.. reminds Us , The continuity-test, & ring-continuity-test ( May-confirm-polarity )

Which of the following is themost suitable instrument to conduct a polarity test ?
a) a high resistance ohmmeter.
b) a bell set.
c) an insulation resistance tester.
d) a low resistance ohmmeter.

GN-3 . P/82 : Low-résistance-ohmmeter(s)
The instrument used for , low-résistance-testsmay be either a specialised low-resistance-ohmmeter
Or
Thecontinuity-range of an insulation & continuity-tester .

It is recommended that low-resistance ohmmeters used for continuity measurements should have a no-loadvoltage and a short-circuit current of ?
a) Voltage between 4V and 24V; short-circuitcurrent of 200mA. ( 612.2.1. ) GN-3 -
b) Voltage between 0V and 24V; short-circuitcurrent of 100mA.
c) Voltage between 4V and 20V; short-circuitcurrent of 1mA.
d) Voltage between 0V and 20V; short-circuitcurrent of 1mA.

-&-s do Something for a Reason !! ( Competent Person )

GN-3 /39 Insulation-résistance . Re-cap . ( 2 )
Note : Pilot or indicator-lamps, aredisconnected from circuits to avoid an , inaccurate-test-value being obtained .

GN-3 /76 . 2392-10 / 2394. Functional-tests, Functional-testing . ( 612.13.2.)
Functional-tests of ( Circuit-breaker(s) Isolators’ & Switching-devices .

 

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Understand therequirements for initial verification of electrical installations
Assessment criteria

2.1. state the purpose of the Initial Verificationof electrical installations
2.2. state the requirements of theinitial verification
2.3. identify the relevant documentsassociated with the inspection, testing and commissioning of an electricalinstallation
2.4. specify the information that isrequired by the inspector to conduct the initial verification of an electricalinstallation

Regulation have stated thefacts .

Certification & Reporting .
631.1. P/195
Upon completion of the ( Verification of a new Installation) Or changes to anexisting-installation, an EIC , shall be provided, Such documentation shallinclude details of the extent of the installation covered by the Certificate,
Together with a record ofthe inspection, the results of testing and a recommendation for the interval untilthe , first-periodic-inspection .

Initialverification procedures :
Weinspect and commission material after the completion of work for three key reasonsto ensure:
□ Compliance with BS7671
□ Compliance with theproject specification (commissioning)
□ That it is safe to use. ◄ . The most important requirement .BS-7671:2011.

Compliance with BS 7671:2011:
BS 7671 Part 6 states that every electrical installation shall,either during construction, on completion, or both, be inspected and tested toverify, so far as is reasonably practicable, that the requirements of theRegulations have been met.

In carrying out such inspection and test procedures, precautionsmust be taken to ensure no danger is caused to any person or livestock and toavoid damage to property and installed equipment

BS-7671:2011: requiresthat the following information be provided to the person carrying out theinspection and test of an installation:

□ the maximum demand ofthe installation expressed in amperes per phase
□ the number and type oflive conductors at the point of supply
□ The type of earthingarrangements used by the installation, including details of ( Equipotentialbonding arrangements ) making me Equal
□ the type andcomposition of circuits, including points of utilisation, number and size ofconductors and types of cable installed ( this should also include details of the‘ reference installation method ’ used )
□ the location anddescription of ( Protective-devices )- ( fuses, Circuit breakers ,RCDs , RCBOs etc.)
□ details of the methodselected to prevent danger from shock in the event of an earth fault, e.g.earthed equipotential bonding and automatic disconnection of supply
□ the presence of anysensitive electronic devices. ... 612.3.3. refer - Note Additional-precaution’s . Etc

It is important to remember that periodic inspection and testingmust be carried out on installations to ensure that the installation has notdeteriorated and still meets all requirements. Tests will also need to becarried out in the event of minor alterations or additions being made toexisting installations.

Once the installation is complete, we need to test it againstthe original specification for the work. This is in order to check that the finishedinstallation matches the requirements laid out by the customer and is fit foruse in the environment where it will be used. The tasks involved in checking compliancewith project specification are as follows.

Pre-commissioning - this involves a fullinspection of the installation and the carrying out of all tests requiredbefore the installation is energised ( continuity,polarity and insulation resistance ).

Commissioning - includes all tests whichrequire power to be available, e.g. the measurement of the earth-fault-loop-impedance and functional-testingof residual-current-devices (RCDs).

As commissioning involves the initial energising of aninstallation, this task has to be carried out in a controlled manner with theknowledge of everyone involved. This means that all other persons working onsite at the time of the energising must be taken to prevent danger.

The commissioning process is intended to confirm that theinstallation complies with the designer’s requirements. As such, commissioningincludes the functional testing of all equipment, isolation, switching,protective devices and circuit arrangements.

 

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Safe to use : As a Competent-person .

The final act of the commissioning process is to ensure the safeand correct operation of all circuits and equipment which have been installed,and that the customer’s requirements have been met. This will also confirm thatthe installation works and, more importantly, will work under fault conditions;after all, it is under fault conditions that lives and property will be atrisk.
The testing of electrical installations can cause some degree ofdanger; it is the responsibility of the person carrying out the tests to ensurethe safety of themselves and others. Healthand Safety Executive Guidance Note GS38 (Electrical test equipment for use by electricians ) details relevant safetyprocedures and should be observed in full.

When using test instruments the following points will help toachieve a safe working environment.

The person carrying out the tests must have a thoroughunderstanding of the equipment being used and its rating.

The person carrying out the tests should ensure that allinstruments being used conform to the appropriate British Standard, i.e. BS-EN-61010or older instruments manufactured to BS-5458 (provided these are in goodcondition and have been recently calibrated).

 

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Competenceof the inspector : Exams , Writing

considerationwhen carrying out inspection and tests is the competence of the inspector. Anyperson undertaking these duties must be skilled and experienced and have sufficientknowledge of the type of installation. It is the responsibility of the inspectorto:

- ensure no danger occursto people, property and livestock
- confirm that test andinspection results comply with the requirements of BS-7671 and the designer’s requirements
- express an opinion as to the condition of theinstallation and recommend remedial works
- make immediaterecommendations, in the event of a dangerous situation, to the client toisolate the defective part.

Operatingdevices
It is not an adequate precaution simply to isolate a circuitelectrically before commencing work on it. It is vital to ensure that once a circuit oritem of electrical equipment has been isolated, it cannot inadvertently beswitched back on. ( Locking-OFF )

method of providing full electrical and mechanical isolation isto lock off the device (or consumer-unit, distribution board containing the device) with a padlock

A skilled person should bethe only one allowed to carry out this or similar responsible tasks concerningthe electrical installation wiring.

 

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Test-procedures 612.2.1.

Continuity of protective-conductors and equipotential-bonding-conductors

Exams, -&-s would like to here this first . Where the installation can be safely isolated from the supply,

(CPC ) Circuit-protective-conductors andequipotential-bonding-conductors can be disconnected from the main earthing terminal in order to verify their continuity.

Wherethe installation cannot be isolated from the supply, the circuit protective conductorsand the equipotential bonding conductors must not be disconnected from the mainearthing terminal,

Under –fault-conditions , extraneous metalwork could becomelive.

Underthese circumstances a combination of inspection,continuity testing and earth loop impedance testing should establish theintegrity of the circuit protective conductors.

 

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It’s all in the wording . 2394

Exams, -&-s would like to here this first . Insulation-resistance-tests canonly be carried out where it is possible to safely isolate the supply.

 

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Some Extracts , HSE – Guidance .

No circuit should bemade available for use until it has been fully-completed & inspected & tested in accordance with BS-7671: :icon_bs:
Including checks toensure that earthing-arrangements & protective-conductors ( includingmain-protective-bonding-conductors ) are in place : &

Anycircuit that is ( Incompleteor has yet to be fully inspected & tested ) must remainsecurely-isolated at the , Supply-end .