Ring final fault - please help !

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I'm doing a PIR on my flat and I've come across a fault I can't work out.

I'm getting a very low (about 0.1Meg Ohm) insulation resistance between Neutral and Line conductors on one of the ring circuits. However I'm not getting continuity between Line and Neutral and the MCB isn't tripping.

The symptoms would suggest there's a load on the circuit somewhere but I've unplugged everything attached to the ring and disconnected the neon in the fused spur to the washing machine.

I was getting continuity (230 Ohms) together with a low insulation resistance until I located a bell transformer spurred from the ring.

When I detached the transformer the continuity disappeared and I thought I'd cracked it......but the low IR remained.

The ring is wired in singles in steel conduit.

Does anyone have any ideas on my current situation

Any thoughts wold be appreciated.

Al

 

[Deleted member 9648]

There will be a load somewhere you have missed....TV amp in loft?.....boiler?.....

 

[Phil]

amp, boiler, outside light spurred off the ring, wall light spurred off the ring?

 

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Hi wirepuller + phil,

Just as I posted I had a brain wave (or doh ! moment). There's a small storage cupboard outside my front door.. just opened it up and there's an unused thermostat on the wall.
I'll pull all the rubbish out and give it a test tomorrow.

Ta

Al

 

[kung]

grrrrrrrr singles ! Reading borough councils fav ! was on a 36 rewire project last year with them ! Good luck as said boiler etc we get nice things spurred off all sorts in our game ! split ring and test both legs then split faulty leg etc

 

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Thanks kung,

Started splitting the ring up but like you said..the joys of single.. it's not easy to guess what point is next in the ring.

..bit of a mind bender..

fingers crossed for the redundant thermostat : )

 

[Phil]

let us know

 

[kung]

Could be one for the tell us your faults post !

 

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Well Gentlemen...

The thermostat wasn't the problem. It was attached to exactly nothing !

BUT.. during some spring cleaning this morning my wife drew my attention to a hollow sound as the hoover hit the wall behind some storage boxes.

It looks like there's an old fireplace behind the panel which I hope is the cause of the problem.

They did such a good job of paneling it in you really have to squint to see the join ...

Club hammer and bolster time on Wednesday

Al

 

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Soo....

At the risk of looking like a complete idiot, I've decided to post my findings.

When I got the time I took a hammer to the sealed fire place and successfully made a complete mess of the wall.

And behind the plaster board was ..wait for it.....

absolutely bugger all !

My only option was to split the ring in stages and hope to identify the problem.

And....

my first IR test at the board showed NO FAULT.

I'd found this fault twice having taken out all appliances and loads on two separate occasions !

The head scratcher for me is the fact that mis-test on a IR test would give a satisfactory (High M ohm) result. My result suggested I was actually testing the circuit and finding something dodgy.

Or maybe I didn't truly take the bell transformer out of circuit the first 2 times.....although pulling out the supply +ve should have done it !.. This time I took it completely off the wall.

My only thought is there's a guy in an upstairs flat with a blown bulb in his spare bedroom.... remember that episode from friends when they couldn't identify what a switch was for ?

One lesson I've learned is test again before getting the big hammer out !

Thanks for the help,

Al