Question regarding signing off 32a ring circuit with broken CPC ring continuity

ZEDEZ · Mar 18, 2019

I installed a kitchen ring recently. Went back to test after the builders had finished and found that the CPC is broken somewhere inaccessible, everything else tests normal. I’ve got continuity on live conductors, and even with the broken CPC, each socket is connected to the CPC and tests with an acceptable Zs value.

What are my options to be able to sign this off without any destructive investigation / remedial work?

My first thought was to split the ring into two 20a radial circuits. But it would be preferable to leave it connected as a ring for increased capacity.

As far as I understand it the fact that the CPC doesn’t have ring continuity isn’t affecting safety or disconnection times, so is there a reason I couldn’t sign this off and simply note this fact?

magnoliafan89 · Mar 18, 2019

telectrix said:
no they are not.they are stripping cords.

Be honest tel they're for show we both know that

Toneyz · Mar 18, 2019

It would be nice if the OP joined in regarding the broken CPC, is there any junction boxes on this ring or is it completely all new? From experience when a cable has been screwed it has caught one of the other conductors. The OP needs to find exactly where the break is first ( a cable come out hopefully will be the cause) and what loads are likely to be on each leg.

littlespark · Mar 18, 2019

Next time.... check all your cables, link all through with WAGOs and power up the circuit.
Then you’ll know who’s drilled a cable;- the joiner with short masonry drill

magnoliafan89 · Mar 18, 2019

9/10 when i get lack of continuity on one of the cable of a kitchen ring the bugger is in one of the SFS for under counter sockets.

edexlab · Mar 18, 2019

I had this twice before where the same kitchen fitter on two different jobs drilled straight through a t&e and unbelievably took out the cpc and neutral first time and just cpc broken second time

First thing I used to do was mark out cupboard positions and where we'd be chasing cables in , followed by getting the fitter to ok it.....

First time this prat got away with it
as customer wouldn't let us take a cupboard down even though we showed him all cables disconnected and continuity on one leg and lack of continuity, position of chase and cupboard screws, fitter had altered the layout and not thought about his fixings etc

Fitter thought it was funny and laughed it off saying it was our fault and we should do a better job

Managed to replace cable with a jb above a cupboard and fished cable down capping to socket

Second time I got the long lead and went round the suspect area testing to all the cupboard screws got continuity to 2 screws ,
Customer was a pita awkward type who always gets what they want

but I was actually quite glad of this in the end because he went mad insisting Kitchen cupboards were removed so we could sort it out

Fitter went AWOL wouldn't answer his phone but this guy tracked him down and somehow got him to agree to footing the bill for our rework , repairing the ceiling and making good the chases and decorating plus he had to fit cupboards again

bonjovi · Mar 23, 2019

ZEDEZ said:
I installed a kitchen ring recently. Went back to test after the builders had finished and found that the CPC is broken somewhere inaccessible, everything else tests normal. I’ve got continuity on live conductors, and even with the broken CPC, each socket is connected to the CPC and tests with an acceptable Zs value.

What are my options to be able to sign this off without any destructive investigation / remedial work?

My first thought was to split the ring into two 20a radial circuits. But it would be preferable to leave it connected as a ring for increased capacity.

As far as I understand it the fact that the CPC doesn’t have ring continuity isn’t affecting safety or disconnection times, so is there a reason I couldn’t sign this off and simply note this fact?

I would say further investigation needed, I would be surprised if its anything other than earthwire clamped to green sleeving remove cables and check, sorted

snipersmith87 · Mar 23, 2019

4mm circuit 32amp ocpd has a 1.5mm cpc. Why is it different?? I was questioning this the other day. Obviously readings compliant to operate in required time.

DPG · Mar 23, 2019

snipersmith87 said:
4mm circuit 32amp ocpd has a 1.5mm cpc. Why is it different?? I was questioning this the other day. Obviously readings compliant to operate in required time.

You still can't sign a new RFC off if one of the conductors does not form a ring.

snipersmith87 · Mar 23, 2019

DPG said:
You still can't sign a new RFC off if one of the conductors does not form a ring.

No i agree. Im not debating its wrong at all. But for my own interest....say a eicr. Comparing it to the situation i just gave. Electrically is it unsafe??

DPG · Mar 23, 2019

snipersmith87 said:
No i agree. Im not debating its wrong at all. But for my own interest....say a eicr. Comparing it to the situation i just gave. Electrically is it unsafe??

It's unsafe in the sense that you know for a fact a cable has been physically damaged somewhere, and so needs repairing or replacing.

snipersmith87 · Mar 23, 2019

DPG said:
It's unsafe in the sense that you know for a fact a cable has been physically damaged somewhere, and so needs repairing or replacing.

A conductor that in a healthy circuit isnt carrying current and in the event of a fault for 0.4 seconds. Im not by any means promoting broken rings. I get the end to end on line conductors for current carrying capacity. But as i stated before 4mm 32amp. 1.5mm cpc.

DPG · Mar 23, 2019

snipersmith87 said:
A conductor that in a healthy circuit isnt carrying current and in the event of a fault for 0.4 seconds. Im not by any means promoting broken rings. I get the end to end on line conductors for current carrying capacity. But as i stated before 4mm 32amp. 1.5mm cpc.

I see your point, but you can't issue a satisfactory certificate because it doesn't pass testing.

BeardyJaws · Mar 23, 2019

Paignton pete said:
If it's a damaged cable not sure how the cpc is cut and not at least one of the live conductors. Unless it's a loose connection in an inaccessible j/b?

I had a similar fault when carrying out a first visit and found no cpc to some of the sockets. Dug the photos out for you. Some investigation and cutting the back of a kitchen cupboard out revealed a huge lump of silicon and a bunch of holes. Clearly done before the cabinets were put in. Once I had pulled off the silicon you could see the blown apart cable they tried to cover up. By all accounts the kitchen was fitting 4 years ago, metal sockets everywhere and all signed off. Customer wasn’t impressed.

[ElectriciansForums.net] Question regarding signing off 32a ring circuit with broken CPC ring continuity

Wilko · Mar 24, 2019

snipersmith87 said:
4mm circuit 32amp ocpd has a 1.5mm cpc. Why is it different?? I was questioning this the other day. Obviously readings compliant to operate in required time.

Hi - I agree, a radial of 2.5/1.5 cable with B32 OLCP will clear a fault without damage, provided max Zs is met.

Overload is wrong of course

. And in this case the cable may have other damage than the assumed clean break in the cpc.

The_apprentice2.0 · Mar 24, 2019

Split you CPC's at the board (or at a socket face) get your long lead and plug adapter out, locate and identify the fault and go from there! never know may be a quick fix

(couldn't find an optimistic glass half full type of looking emoji) .....

Question regarding signing off 32a ring circuit with broken CPC ring continuity

ZEDEZ

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magnoliafan89

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Toneyz

littlespark

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magnoliafan89

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edexlab

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bonjovi

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snipersmith87

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DPG

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snipersmith87

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DPG

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snipersmith87

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DPG

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BeardyJaws

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Wilko

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The_apprentice2.0

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