Re-take - Useful Information for 2394 :

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Before everything, a safe isolation procedure must be carried out. Periodic-inspecting . :aureola:
What is Insulation-résistance-testing ??
The insulation resistancetest is an electrical-test which uses a certain type and level of voltage ( 500V d.c. for Low-Voltage-installations )

Required-test-voltage& the minimum-required-résistance in accordance with BS-7671:2008:2011:

BS-7671:2011: Sates . The ( Minimum-résistance ) to comply with the Regulation(s)

► Circuit-Nominal-voltage : Between 0V & 50V a.c.
► Test Voltage: 250Vd.c.
► Minimum-résistance : 0.5MΩ

P/191 . Note : ( IR ) values are usually muchhigher than those of , Table – 61 .

► Circuit-Nominal-voltage : Between 50vand 500V a.c.
► Test Voltage: 500V d.c.
► Minimum-résistance : 1MΩ

► Circuit-Nominal-voltage : 500V above , 1000V a.c.
► Test Voltage: 1000 V d.c.
► Minimum-résistance : 1 MΩ

P/31 . Nominal-voltage : ( see-Voltage, nominal )

 

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2392-10 . Overlooked :- The, Why’s ? Megger – 1552

Connect - leads tometer and test , short & open-circuitfor lead-continuity. :35:

 

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[h=3]Useful-junk :[/h][h=3]P/25 , Consumer-unit: [/h][h=3]Were did thatname come from . ( CCU ) Consumer-Control-Unit , BS-7671:2001:2004:2008:2011. :icon_bs:[/h]

 

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[h=3]► BS-7671:1991 : Extracts. Wiring-systems : ( When is a Regulation past it’s Best ) :46:
[/h][h=3]604-10-01. Every-wiring-system shall be so arranged that no-strain is placed on the , terminations of conductors unless such-terminations are designed for this purpose .
[/h][h=3]604-10-02. Cables shall not be run-across a site-road or awalkway unless , adequate-protection ofthe cables-against , mechanical-damage is provided . [/h]

 

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BS-7671:
All Appendices are informativeother than , Appendix 1 which is normative. Appendix1 is a requirement and all others are provided for guidance

 

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Re-cap :

For installation(s) with a 230V –single-phase-supply , rated up to 100A ,that are under the control of Ordinary-persons . ( Switchgear & Controlgear )
Comply with , BS-EN-60439-3 & Regulation - 432.1. P/80 .

Be a , Consumer-unit incorporating-components-complying with , BS-EN-60439-3 .

Switch-disconnections, BS- EN-60947-3.

432.1 . Protection against overload-current ( Only) Etc
For a , Circuit-breaker making, anyovercurrent up to & including the ( Maximum-Prospective-Fault-Current ) at the point where the device is Installed.

P/284 : BS-EN-60439-3:1991 . defined as .
Particular-requirementsfor , ( LV ) Switchgear &Controlgear assemblies intended to beinstalled in places where ( Unskilled-persons ) have access totheir use , Distribution-boards .

BS-EN-60439-3:1991+A2:2001

Low-voltage switchgear and controlgear assemblies. Particular requirementsfor low-voltage switchgear and controlgear assemblies intended to be installedin places where unskilled persons have access to their use. Distribution boards

P/150 . 537.1.4. General-requirements.
A main-switch intended for operation by ordinary-persons , of a household orsimilar-installation , should interrupt, both live-conductors of a ,Single-phase-supply .

537.1.4. A main-linked-switch or linked-circuit-breaker shall be provided as near as practicable tothe origin of every-installation as ameans of switching the supply on load & a means of Isolationswitch

P/29 . Isolation :- is the function that Allows operatives to work-safety onelectrical-equipment. BS-7671:2008:2011: as defined as :

A “ function-intended to cut off for reasons of safety the supply from all ,or a discrete-section , of the installation by separating the installation orsection from , every-source of electrical-energy

RCCBs , are devicesdesigned to protect against , fault-currents flowing to earth,

 

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Testing . 2392-10 .
Test-method 1 : use the Line-conductor as a return-lead , Otherwise known as the ( R[SUP]1[/SUP]+ R[SUP]2[/SUP] ) method .
Résistance of the ( CPC )
Q . Why do I need to bother with the, Résistanceof the Line-conductor ?
Reason being : can use Line-conductor as part of the circuit . ( Willyou use a Wander-lead , NO )
Reason : Your ( R[SUP]1[/SUP] + R[SUP]2[/SUP] ) reading can be used for working out your ,Earth-fault-loop-impedance-value . (Circuit-loop-impedance )
Have you , Obtained Polarity . at the same-time . ( L / CPC )
Most used methodused for ring-final-circuit(s) Line-conductor runs alongside a ( CPC ) conductor , factor is utilised in this Test . :yes:

 

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2392-10 . better-understanding.

Test-method 2 : uses the , Wander-lead , it’s title ( R[SUP]2[/SUP] - method)

Your Reason . Wander-lead is a simply a long-length of conductor that can be moved to different-points . in anInstallation .

( R[SUP]2[/SUP] - method) confirm the continuity of , Equipotential-bonding-conductor(s) 612.2.1. :svengo:

2392-10, you do not have a, Line-conductor as a return-path. “ Simple “

 

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For , safety-reasons ... (You may have Implication(s)

( R[SUP]2[/SUP] - method)
Ensure that you have the permission beforehand ( Disconnectany parallel-paths) main-protective-bonding-conductor . Etc

 

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Design-Procedures : of Any- BS-7671: 2392-10 : As , Installers / Designers.

Safety of , Life & Property, are the first-two-important-factors to be considered in the ( Design ) of low-voltage-systems.( LV )

 

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2392-10:- How significant is Insulation-résistance-testing !!

Insulation starts to age as soon as it's made. And, agingdeteriorates its performance.

Installation-résistance-test : Integrityof Conductor(s).

Insulation-résistance, confirmthe reliability of the circuit , in question .

( shorted-connectionwould be obvious from the test-results)

Initial-verification: 2008:2011:
Every-installationshall , during-erection & on-completionbefore being put into service , be . ( Inspected & Tested to verify )

Regulation - 612.3 ( Under-the-section for Initial-verification) :icon_bs:

GN-3 : States :
Insulation-résistance-testedduring various-stages of installation to ( Prove ) the integrity of installed-cables .

 

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2392-10 , thereis always a reason, when I post anyarticle(s) for your benefit . ( can you HIT the Thank-you-button)

 

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( 1MΩ / 2MΩ ) Extracts.

2008: GN-3 , States :

Whole-installation, Periodic-testing... ( Existing )
Single-circuit(s), Initial-Verification... ( New-installation )

Insulation-résistance to Earth.
Single-phase .
Test between the line &neutral-conductor(s) connected together& Earth at the appropriate , distribution-board, of for circuits /equipment not vulnerable to ,insulation-résistance-testing , line & neutral-separately to Earth .
For circuits containing two-way-switching ortwo-way & intermediate-switching ,the switches must be operated one at a time & the circuits subjected to additional-insulation-résistance-test(s)

Where a low-reading is obtained ( Less than 2MΩ ) it may be necessary to test each-conductor-separately to earth , after ensuring that all equipmentis disconnected .

Résistance-readings obtained should be not less than the ,minimum-values , refer , Table – 61

• If a sufficient-high-reading cannot be obtained on the , ( Whole-installation) GN-3 - requires us to . Test ( On any individual circuit(s) discover where any fault is occurring .

Sixth-edition : Inspection& Testing (GN3) provides us with an opportunity comment onthe critical-importance of the Verification-process.
GN3 is, primarily concerned with Part 6 of BS-7671 – Inspection and Testing.
2392-10 , You are only testing , Single-circuits (T&E ) on Initial-Verification. ( You will not Test , Whole-installation)

 

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fifth-edition- 2008 – GN-3 : P/38 , Extracts .
Although an , insulation-résistance-value of not less than ( 1.0MΩ ) complies with the Regulations , where aninsulation-résistance of less than ( 2MΩ ) is recorded the possibility of alatent-defect-exists , in these-circumstances ,
Each-circuit should be tested-separately .
GN-3 , re-cap .
This will help identify (i) whether one-particular-circuit in theinstallation has a lower-insulation-résistance-value , possibly-indicating alatent-defect that should be ( Rectified) Or
(ii) whether the low-insulation-résistance-represents, for example , the summation of individual-circuit-insulation-résistance &as such may not be a cause for concern .

 

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From , 1991 / 2011 . BS-7671 : :icon_bs:

P/29 . Insulation : Suitable non-conductive-material enclosing, surrounding or supporting a conductor .