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RCD Testing Lighting circuits

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jls...@btinternet.com

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Mar 27, 2008, 2:46:45 PM3/27/08
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As part of the on going rewiring of my house, I have a question about
RCD testing.

I have not actually changed any wiring in the house* as such, but I
changed the CU and I am in the process of fitting RCBOs across all the
circuits in the straight switch box - I thought I'd go 17th compliant
as it seemed more sensible. Besides that configuration makes sense.

*(well, I'm also in the process of fitting rather more equipotential
bonding then was fitted beforehand)

I can (and have) test all the RCBOs on on the mains circuits with my
tester, but my tester has only a 13A sytle plug adapter for testing
mains circuits (is an older unit cheap off fleabay, but it makes me
feel more comfortable that the whole system is working correctly
before I pay my friendly competant to test the whole installation with
test gear that is in cal).

Buying a new tester is not an option, and any with fly leads for
lighting circuits will be beyond any price I deem reasonable for my
"peace of mind" testing. I see three options:-

1. fit a socket on the lighting circuit in near to the consumer unit
and mark it up as "LIGHTING CIRCUIT FOR RCD TESTING RBCO No2" or
something equivalent and then use my RCD tester on that.

2. get an female in line 13A extension cable socket and then make up a
fly adapter of my own to allow my to test lighting circuit. More
fiddly this and much more prone to possible problems - I've got to say
I'm not so keen on this idea.

3. Use on the the test button on the front and wait for my friendly
competant. I'm not so keen on this either - the test button cannot
tell me under what imbalance or how fast the RCD worked.

So, if I fit a socket near to the consumer unit (one for each lighting
circuit) and label them up accordingly this seems to be the best
solution for my particular needs. But that would certainly seem an
unsual solution.

(and all this before I even light a floorboard, sigh - so much more to
do)

Any comments?

Dave Liquorice

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Mar 27, 2008, 5:38:25 PM3/27/08
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On Thu, 27 Mar 2008 11:46:45 -0700 (PDT), jls...@btinternet.com wrote:

> 2. get an female in line 13A extension cable socket and then make up a
> fly adapter of my own to allow my to test lighting circuit. More
> fiddly this and much more prone to possible problems - I've got to say
> I'm not so keen on this idea.

I tempted to say, oh sod it I'll say it anyway, if this is a worry to you
are you actually up to doing the wiring changes in the first place?

--
Cheers
Dave.

John Rumm

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Mar 27, 2008, 6:58:42 PM3/27/08
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jls...@btinternet.com wrote:

> 2. get an female in line 13A extension cable socket and then make up a
> fly adapter of my own to allow my to test lighting circuit. More
> fiddly this and much more prone to possible problems - I've got to say
> I'm not so keen on this idea.

Making up a test lead would be my prefered solution, saves any problem
with the test socket being used inappropriately later. Does your tester
have a IEC socket to connect its mains lead? If you its quite easy to
make a lead.

> 3. Use on the the test button on the front and wait for my friendly
> competant. I'm not so keen on this either - the test button cannot
> tell me under what imbalance or how fast the RCD worked.
>
> So, if I fit a socket near to the consumer unit (one for each lighting
> circuit) and label them up accordingly this seems to be the best
> solution for my particular needs. But that would certainly seem an
> unsual solution.

Seems a little excessive especially since you are in effect using one
RCD per circuit.


--
Cheers,

John.

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jls...@btinternet.com

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Mar 27, 2008, 7:33:47 PM3/27/08
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> Making up a test lead would be my prefered solution, saves any problem
> with the test socket being used inappropriately later. Does your tester
> have a IEC socket to connect its mains lead? If you its quite easy to
> make a lead.

Unfortunately not, else that would of easily been my preferred
solution, its a fixed connection. So any fly lead I make would need to
be on a female inline socket. Thats not really a problem though. I'd
just need to meet GS38 on clips/probes and ensure the earth is cream
for "functional" earth if I remember those regulations correctly (and
you can be damn sure I'll check carefully first). Still the tester
certainly works - its an older model though so I manually need to set
phase, 50%,100% based on rating etc. It will be interesting to see how
its measurements match up to the cal unit from my friendly competant -
the last cal on this unit was a couple of years ago. No doubt the
previous owner moved to one of those switch auto testing ranging ones.
At least if I make up a fly lead that might make testing easier in
some circumstances.

Any other comments welcomed.

J.

Andy Wade

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Mar 28, 2008, 2:46:06 PM3/28/08
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jls...@btinternet.com wrote:

> Unfortunately not, else that would of easily been my preferred
> solution, its a fixed connection. So any fly lead I make would need to
> be on a female inline socket.

Not necessarily: you could cut off the 13 A plug and fit a flying male
IEC connector. Then use a bog standard IEC mains cordset for testing
socket circuits and make up an IEC(f) to croc clips or test prods lead
for use elsewhere. It's the sharp end of the latter lead which you
should make GS38-compliant.

> just need to meet GS38 on clips/probes and ensure the earth is cream
> for "functional" earth

I've not seen that on test equipment. I bought a new Megger loop tester
last year (LTW325) and that uses red for phase and plain green (not
grn/ylw) for earth.

--
Andy

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Andy Wade

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Mar 28, 2008, 5:43:18 PM3/28/08
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m...@privacy.net wrote:

> I have an iec lead to an old connector that fits bayonet lampholders (and a
> croc clip earth lead) for use on lighting circuits.

50:50 chance of getting the polarity wrong, and just turn it round if
you do, presumably? No use for polarity testing though.

--
Andy

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