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Marcus Vaughan

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Hi all,

I was hoping to sneak in a little job late this afternoon - changing a faulty bathroom pull chord for an outside switch plate. No problems with access. Straight forward enough.

House is almost certainly post 60's. CPC's present in lighting circuit.

Live Zs = open circuit.
R2 test with wander lead from MET to as many lighting JB's in the loft I could find = 60 k ohms.

So there is some sort of reading.

Loose connection?

Back tomorrow so any advice on where to start always appreciated.

It looks like the lights are wired in single line + cpc, looped in an out using every which method you can think of, and a neutral looping around each load.

Like I said - where to start.

There are other circuits available in the loft - I could bridge across from 1 JB to another with some 4.0mm if I have to (I suppose).
 
Hi all,

I was hoping to sneak in a little job late this afternoon - changing a faulty bathroom pull chord for an outside switch plate. No problems with access. Straight forward enough.

House is almost certainly post 60's. CPC's present in lighting circuit.

Live Zs = open circuit.
R2 test with wander lead from MET to as many lighting JB's in the loft I could find = 60 k ohms.

So there is some sort of reading.

Loose connection?

Back tomorrow so any advice on where to start always appreciated.

It looks like the lights are wired in single line + cpc, looped in an out using every which method you can think of, and a neutral looping around each load.

Like I said - where to start.

There are other circuits available in the loft - I could bridge across from 1 JB to another with some 4.0mm if I have to (I suppose).
What was your MFT set on?
 
Check in the board for the presence of a cpc.
 
I would do a R1 +R2 at other lights on the circuit.

In a house of that age CPC's may be present, but they may not have been connected up.....
 
I would do a R1 +R2 at other lights on the circuit.

In a house of that age CPC's may be present, but they may not have been connected up.....
Yep, link at CU and test at the lighting points first.
Although, are you saying the lives are looped at the switches and neutrals at lights? If so, switch 'em on first:rolleyes:
 
I have found an older (red an black) 1mm twin and earth cable with the earth discontinuous in part of the run. Either a manufacturing defect or the 1mm pulled too hard during installation I reckon, as the cable appeared ok externally.
 
I have found an older (red an black) 1mm twin and earth cable with the earth discontinuous in part of the run. Either a manufacturing defect or the 1mm pulled too hard during installation I reckon, as the cable appeared ok externally.

And this is exactly why I tell apprentices to check for continuity at EVERY point/accessory. You never know if the cable inside the sheath is continuous or has snapped and pulled a part!!

Jay
 
Does the home owner have the certificate for the installation of the CU? The schedule of test results could make interesting reading

I’ll ask. I was thinking that because I was getting 50k ohms rather that complete open circuit that the install designed to be earthed but something has gone wrong somewhere. I have already sorted out a couple of tapped up connections outside of enclosures - that sort of thing.
 
the reading you are getting could be a return path via the filament of a bulb and the neutral.

You need to do proper dead tests........
 

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