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Topic Title: Testing Ring Circuits on a Periodic Inspection
Topic Summary: Is it ok to test at a socket outlet?
Created On: 05 April 2013 04:56 PM
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 05 April 2013 04:56 PM
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keithredpath

Posts: 416
Joined: 30 March 2002

Is there any reason why, when carrying out ring circuit continuity testing, you can't test at a socket outlet instead of at the distribution board?

Also, should we carry out Figure of Eight tests during a periodic inspection?

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keithredpath
 05 April 2013 05:22 PM
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Legh

Posts: 3478
Joined: 17 December 2004

Its debatable IMO.
If it says its a RFC on the box then it must be so - I think not, however......
1/ Documentation, previous test results should tell you what the circuit is and what values were obtained - somewhat unlikely, particularly on some of the EICR/PIRs I've done
2/Unless additions, alterations and repairs have been carried out it might be assumed that the RFC is still the same - you can never be too sure though .
3/ If you get satisfactory loop readings then there is no need to rip everything apart.
4/ If there is a reasonable doubt then its up to you to check.
5/ An end to end and figure of 8 can be done at either the origin or at a socket on the ring.

I usually check RFCs as a matter of course but then it depends who did the work previously and whether there are previous results available. In this case I would be happy just to verify that compliance with the tables in chapter 41 was achieved by loop testing and inspection.

Legh

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 05 April 2013 05:55 PM
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daveparry1

Posts: 6151
Joined: 04 July 2007

Continuity and Zs are my main concerns with rings when doing eicr's, and yes it's fine to test at a socket outlet or fcu,(I don't often do eicr's, more trouble than they're worth I think!)

Dave.
 07 April 2013 01:06 AM
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jimmyoneball

Posts: 23
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Yes of course you can do the end to end from a socket outlet. It is often much easier if the CCU is too high or in a daft cupboard.

The figure of eight is an essential test as you need to determine the R1+R2 of the RFC however very easy and quick to do with those wago clips or even nip the ends together with your fingers and press the test button with your nose as I often do!

A ring within a ring is sometimes obvious from a very low R1+R2 value.
 07 April 2013 01:22 PM
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MrP

Posts: 832
Joined: 24 March 2006

Originally posted by: keithredpath

Also, should we carry out Figure of Eight tests during a periodic inspection?


Keith
You don't have to test anything or take any covers off
you do what's agreed
and that is usually dependant on the fee

MrP big sand storm
 07 April 2013 09:38 PM
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BrucieBonus

Posts: 666
Joined: 20 February 2007

I would always the 'figure of eight' test on what might be ring circuits. In a domestic situation there are pretty much never any previous certs and I would say that at least 50% don't test out as spur-spur-spur have been added. Or rings broken and cannot be remade without a lot of hassle.

A broken ring on a 32A breaker would be a code 2 anyway, so you couldn't pass it...
 08 April 2013 07:04 AM
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primo

Posts: 431
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I would say fine to test at a socket outlet.
Definitely worth carrying out the fig8 test. It doesn't take much longer to include this test. Rarely do the results fall within the exact limits of what they should be but that's usually down to the contacts at the sockets but, if you don't do the fig 8 test (properly, i.e. at every socket !) and its a non RCD protected circuit then you could easily miss a neutral - earth reversal as this wouldn't show up on a Zs.
 08 April 2013 09:02 AM
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Jaymack

Posts: 4617
Joined: 07 April 2004

Originally posted by: primo
but, if you don't do the fig 8 test (properly, i.e. at every socket !) and its a non RCD protected circuit then you could easily miss a neutral - earth reversal as this wouldn't show up on a Zs.

Testing for continuity at a socket outlet, is a method recommended on an NICEIC DVD, when it is easier than at the D.B. On an E.I.C.R., don't you test for Zs at each socket? I find reversals of the Lives on many occasions!

Regards
 08 April 2013 12:32 PM
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primo

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Yes I do test Zs at every socket! But this wouldn't pick up a N-E reversal on a non RCD protected circuit, hence why I think that a proper ring R1R2 should be carried out at every socket.
 08 April 2013 01:09 PM
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Jaymack

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Originally posted by: primo
But this wouldn't pick up a N-E reversal on a non RCD protected circuit

What are the connections required, for a Loop Tester at a socket outlet or any other live circuit, in order to determine Zs?

Regards
 08 April 2013 06:14 PM
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primo

Posts: 431
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I can't comment for other testers but if you use the plug adaptor for the Fluke 1652 you will not detect a N-E reversal when carrying out a Zs at a socket outlet.
So if you were to omit R1R2 testing for a ring and just rely on the Zs results you could easily miss a N-E reversal (I'm sure we've all discovered one somewhere), but of course this limitation on the testing would have been agreed and written down on the report so no comeback there then.
 09 April 2013 03:43 PM
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Jaymack

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Originally posted by: primo
I can't comment for other testers but if you use the plug adaptor for the Fluke 1652 you will not detect a N-E reversal when carrying out a Zs at a socket outlet.

Is that correct? Then it's not measuring Zs and not fit for purpose.

Regards
 09 April 2013 03:50 PM
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AJJewsbury

Posts: 11349
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Is that correct? Then it's not measuring Zs and not fit for purpose.

How would any plug-in instrument find a N-PE reversal? There'd still be 230V L-N and L-PE and near zero volts N-PE.

- Andy.
 09 April 2013 04:36 PM
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Jaymack

Posts: 4617
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Originally posted by: AJJewsbury
Is that correct? Then it's not measuring Zs and not fit for purpose.

How would any plug-in instrument find a N-PE reversal? There'd still be 230V L-N and L-PE and near zero volts N-PE.

Indeed, I was thinking of an L and N reversal. ............... Must read the posts correctly, must read the posts correctly! must read the posts correctly! must read the posts correctly!

Regards
 11 April 2013 09:02 AM
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AJJewsbury

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Just a thought - perhaps obvious anyway, but just in case. If you're testing end-end continuity at a socket rather than the CU, do make sure that the individual MCBs are off or fuses pulled, rather than just isolating by the main switch or RCD. It's not a safety issue, but to make sure you don't get false results if say one leg of a ring has been swapped with the immersion (oldest trick in the book) and L-L continuity appears satisfactory only because it's completing the circuit via both fuses/MCBs and the bus-bar.
- Andy.
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