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Topic Title: IR Test at the socket for a ring circuit
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Created On: 16 April 2018 12:22 PM
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 16 April 2018 12:22 PM
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GKServices

Posts: 31
Joined: 20 December 2017

Hi all - some of the CUs I come across are so untidy it can take a while to work out what is incoming and outgoing on the ring - Do any of you do your IR test at one of the sockets on the Ring - I know the regs is all about everything at the CU but saves time and same result I would have thought?
 16 April 2018 01:43 PM
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daveparry1

Posts: 7978
Joined: 04 July 2007

I have done this occasionally but you have to remember to turn the main switch off or you'll read a short between N & E!
 16 April 2018 01:45 PM
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dustydazzler

Posts: 2772
Joined: 19 January 2016

For fault finding maybe

But for a eic or eicr I would want to identify the legs of the ring at the board and test from there

Even if it meant an extra 5 mins on the job faffing about in the board
 16 April 2018 02:09 PM
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mapj1

Posts: 11566
Joined: 22 July 2004

It can depend on access. If I find I am struggling to get my head and the meter into a cupboard with a low ceiling, and a floor that the builders have made hard to kneel on by adding dried peas to the cement, I may well take the meter to a socket and restrict operations in the CU to those that involve removal and reconnection of wires, and the odd test link with a lever wago or similar.

Also my eyesight is now at a stage where for finer things I either need to be putting glasses on and off like Prof. Branestawn or my arms need to be just the right length, and especially if the light is poor, it is can sometimes be easier to relocate to somewhere easier to work, and reduces the risk or misreading.
Of course care must be taken that the testing really is electrically equivalent, and the right circuits are isolated, but it certainly can be done.

-------------------------
regards Mike
 16 April 2018 02:22 PM
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AJJewsbury

Posts: 17444
Joined: 13 August 2003

Provided you're also proving continuity between the CU and your chosen socket (e.g. so L-PE test isn't just reading clear because the earth wire has dropped out of the terminal in the back of the socket) - then I see nothing wrong in testing at a socket. Indeed when testing an existing installation the less dismantling the better I say - so if you can do it by plugging in rather than disconnecting, testing and re-connecting (so your re-connection - hence what's actually put back into service - isn't subject to the test) - there's a clear advantage to my mind.

Expanding on daveparry's point though - do be wary that switching off a single pole MCB does little to isolate the circuit you're testing from everything else in the installation - it's easy to get low IR readings due to fault on a difference circuit and your L being bridged to the common N by an overlooked load somewhere.

- Andy.
 16 April 2018 02:24 PM
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dustydazzler

Posts: 2772
Joined: 19 January 2016

If one is to test for a ring at a socket outlet and finds an open ring (crab claw if you will) , you still need to get badgering around in the board anyways
 16 April 2018 05:21 PM
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chrispearson

Posts: 760
Joined: 15 February 2018

A ring is a ring, is it not?

Do your ring continuity tests where you like, but I don't quite see how this is relevant to IR testing, especially if you do a whole-board test.
 17 April 2018 10:31 AM
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AJJewsbury

Posts: 17444
Joined: 13 August 2003

Do your ring continuity tests where you like, but I don't quite see how this is relevant to IR testing, especially if you do a whole-board test.

Some inspectors have been known to IR test an entire installation by switching off the main switch at the CU and testing via a plug in the first convenient socket.

- Andy.
 17 April 2018 10:54 AM
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ebee

Posts: 6597
Joined: 02 December 2004

That should effect a global IR test, all other circuits being connected of course.

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 17 April 2018 06:14 PM
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tillie

Posts: 916
Joined: 03 May 2006

Hi , surely this test cannot be carried out on an installation with rcbos or rcds.

I have no problem testing 500v through double pole rcds but on most if not all rcbos it tells you not to insulation resistance test through the device.

I have bench tested rcbos with 500v and have found that it does not seem to affect them at all and the tripping times remain the same.

Obviously I have no intention of using them but it was nice to know.

I have found that if you disconnect the earth flying lead then you can test the whole board L/N to earth.

Regards
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