Neutral on the wall?

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beemer

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Help Please!

Had to go to a job where a socket front was faulty, I changed the socket front and just to make sure, I checked the whole circuit for continuity and Ins Res. That's when I found a peculiar fault:

I had disconnected the Kitchen ring from the CU, and found that I had a 1.9 Meg Ohm reading between Neutral and Earth only.

After a series of testing I discovered that I would only get this reading when the earth is connected to the metal back boxes (only two metal in the whole ring, the rest is dry wall boxes).

I checked the cables coming through into the metal boxes and they were sound with healthy grommets in position.

The only possibility is perhaps a Neutral cable having been nicked by a screw in the wall. I know that the reading complies with BS7671 but I still would like to know what it is and how I can remove the fault.

Your help appreciated.

Thanks Dave.

 

beemer

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DaveIs it an old house if so maybe a damp problem.

Batty
This is on an internal wall. The kitchen was extended several months ago, the wall newly plastered, and a new kitchen installed (hence my thought on a screw through the neutral).

Could I have a 'Neutral leak' into the wall (for want of a better phrase)?

 

Nicky Tesla

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Have you dissed the neutrals from the DB

Are there any neons on the sockets

Is anything still plugged in or connected eg. extractor fan?

 

steptoe

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is it TNCS?

you could be having a parrallel path from the Earth via backbox to another circuit backbox (or water pipe) then back to earth again, which is also Neutral on TNCS.

even tho the cables are seperate you still have other circuits to contend with.

either that or a metal clad with a neon or similar, tho I would tend to favour the boiler/imm htr and water pipe thought myself.

would be very likely via a boiler/imm htr circuit or similar.

 

seajayess

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As steptoe said if its TNCS could be path back between N/CPC try switching of the Main swith then try it again as this will diconnect the TNCS system CJS

 

beemer

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As steptoe said if its TNCS could be path back between N/CPC try switching of the Main swith then try it again as this will diconnect the TNCS system CJS
Now then, there's a thought! my notes are in my van so will try that thanks Seajayess and Steptoe for your ideas :)

Yes Nicky, I disconnected everything in the end to try and find where the minor fault was, no neons and I checked every cable between sockets too, all were ok with 1000+ Meg Ohm readings.

 
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