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Topic Title: insulation resistance testing on a EICR/PIR
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Created On: 06 March 2013 06:49 PM
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 06 March 2013 06:49 PM
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newelectrician

Posts: 13
Joined: 05 July 2011

have read in 'unite the union guide to inspect and test'

test carried out with L/N joined to Earth and no need to disconnect loads/vunerable devices

pic1 to test whole insulation, shows link between L/N (incoming) at main switch with supply isolated.

Q. if linked on incoming side of main switch and switch is off, then i wouldnt be testing pass the switch, would i? also if linking on incoming side then i am working live?

Pic2 to test individual circuit shows link between mcb and N bar

Q if linked in this way can other circuits affect reading because they will still be connected via N bar.

i have tried method in pic 2 and getting strange readings

also if possible would someone please explain the best way to test whole insulation for IR on a EICR/PIR with vunerable device/loads still connected (switches closed)
eg how/where they would make link etc

very new to this, so would appreciate help, thanks
 06 March 2013 07:07 PM
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Legh

Posts: 3489
Joined: 17 December 2004

Originally posted by: newelectrician

have read in 'unite the union guide to inspect and test'

test carried out with L/N joined to Earth and no need to disconnect loads/vunerable devices

Are you not measuring between L/N and PE ?

pic1 to test whole insulation, shows link between L/N (incoming) at main switch with supply isolated.

Q. if linked on incoming side of main switch and switch is off, then i wouldnt be testing pass the switch, would i? also if linking on incoming side then i am working live?

Not wise to link the incoming L/N - very big Caboom . and you may not be working at all . Surely you mean outgoing, installation side of the isolator ?

Pic2 to test individual circuit shows link between mcb and N bar

Q if linked in this way can other circuits affect reading because they will still be connected via N bar.

You are measuring between the shorted out Neutral to each phase conductor of the circuit and the Protective earth (PE)

i have tried method in pic 2 and getting strange readings

also if possible would someone please explain the best way to test whole insulation for IR on a EICR/PIR with vunerable device/loads still connected (switches closed)

eg how/where they would make link etc

The phase and neutral is shorted out for each test to PE so one would hope you will not be measuring across any load. However, those little filter circuits connected to PE within certain appliances can often cause strange readings

very new to this, so would appreciate help, thanks


This is a start

legh

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 06 March 2013 07:40 PM
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newelectrician

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Joined: 05 July 2011

sorry i wasnt very clear measure between L&N joined and Earth

picture clearly shows link between incoming L & N with supply isolated (is it poss to post pic on here?)

was testing my sub board in outbuilding,

main switch rcbo 63amp
1) mcb type b 32a - ring with 3 sockets (no load)
2) mcb type b 32a - ring with 8 sockets (no load)
3) mcb type b 6amp with 2 fluorescent lights (is this the problem)
4) mcb type b 6amp with 3 lights (GU10 4 lamps on)

now when i test (250v, just as precaution) circuit 4 with all conductors pulled out get >99M
but when i test via pic 2 description i get 45-50M

is it FLU affecting readings via N ?

how would you IR whole install on PIR
 06 March 2013 09:46 PM
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jcm256

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 06 March 2013 09:48 PM
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newelectrician

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Joined: 05 July 2011

can i post pics from book on here ?
 06 March 2013 09:57 PM
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newelectrician

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Joined: 05 July 2011

thanks for everyone help on this
 06 March 2013 10:55 PM
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sparkingchip

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Joined: 18 January 2003

Being an older electrician, I have the Amicus-AEEU BS7671:2001 version of the book with a yellow cover., same diagrams are in it.

It shows the testing of a complete NEW installation before it is connected to a electricty supply and testing is carried out on on the dead meter tails.

IF YOU TRY THIS ON A PIR/EICR INSPECTION AND TEST WITH LIVE METER TAILS YOU WILL CAUSE A EXPLOSION AND INJURE OR MAYBE EVEN KILL YOURSELF OR OTHERS.

Andy

Actually there is a note about testing circuits individually if the client won't allow everything to be turned off at the same time.

Major issues here! Not the best of books for researching insulation testing, even though it is one allowed in the exam room.

Edited: 06 March 2013 at 11:01 PM by sparkingchip
 06 March 2013 11:20 PM
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sparkingchip

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Joined: 18 January 2003

That link to a Irish website is misleading as well, unless of course you are in Ireland.

It sets out the requirements for a kitchen equipotential zone, which are not requirements of BS7671 2008:Amd.1:2011

Andy

There are lots of things on the Irish website that differ from the requirements of BS7671 2008:Amd.1:2011 learning it off by heart won't get you through a exam unless you are in Ireland.

Edited: 06 March 2013 at 11:29 PM by sparkingchip
 07 March 2013 11:38 AM
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newelectrician

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Joined: 05 July 2011

someone posted me a pic of the older version on a different forum(link below), slightly different. i have spoken with tech help where my book came from and they were aware of misleading/incorrect picture. i suppose the one good thing to come out of it, is that even though i very new to this testing malarky i shouldnt have doubted myself because the book was incorrect.

http://www.electriciansforums....ce-test-eicr-pir.html

thank you everyone for your help.
 07 March 2013 12:34 PM
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AJJewsbury

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Joined: 13 August 2003

different forum(link below)

Beware of the advise to "Either disconnect the earth conductor to the board you are testing, or the main earthing conductor for the installation."

Its a recent requirement, but BS 7671 requires insulation tests to earth (c.p.c) do be done with the connection to the means of earthing intact - so it can spot faults to true earth as well as faults to c.p.c.

- Andy.
 08 March 2013 06:38 AM
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ebee

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Joined: 02 December 2004

I`ve always followed that one on IR Andy, even when told it`s not required

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