Help Required. electrical circuit problem

The funny thing about this is that IT WAS ME...

I'd forgotten that four days earlier the top of the mixer tap came off when filling the kettle. Luckily I'd only asked the wife if she had any ideas how this happened, and didn't accuse her. Phew!

I guess this is how the water got there, but am suprised that the problem took four days to happen?

Reply to
OceanTragic
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Here's an update:

Just as a reminder I have two radials with the cable that used to join them together being identified as where the problem lies. I've re-connected the duff cable to one of the radials and it still trips the breaker. (Shame it didn't fix itself automatically after a long wait!!)

I put a new cable in to join the radials and everything worked fine. I could just go ahead and put this in place but it'll take me quite a while and I'd really like to find out what the original problem is. So I ran a few tests...

Tested continuity on duff cable:

  1. at one end of the cable I tested L-E and N-E and no problem exists, but this was only with a simple continuity test. Martin mentioned that I need to test using "an insulation tester that puts 500V across the conductors" but I'm not sure my simple multimeter can do that. It does other options for resistance (2Kohms, 20Kohms, 200Kohms, 2000Kohms) but I've never used these. Are they any use?
  2. at one end I linked L and E and at the other end tested continuity and results were as expected
  3. at one end I linked N and E and at the other end tested continuity and results were as expected
  4. at one end I linked L and N and at the other end tested continuity and results were as expected
Reply to
OceanTragic

"OceanTragic" wrote in message news:di847u$arg$ snipped-for-privacy@newsg3.svr.pol.co.uk...

Oh but if only life was like that :-)

What the insulation test does is to introduce double the supply voltage to a circuit. Sometimes a circuit will test OK at the voltage of a continuity tester but as soon as mains voltage is introduced, the insulation breaks down. Apart from that the IR tester is basically an Ohmmeter and you would expect to see at least 1 Megohm between conductors.An insulation resistance tester comes as a suite of testers that electricians have. Your tester won't do it I'm afraid.

It does

If your meter is not autoranging you would have to select these levels depending on the resistance you were measuring. Let's say you were in 2K ohms you were measuring open circuit, you then switch to 20K ohms and try again until you find a level that gives you a reading. If you get to 2000K ohms and still showing open circuit then it is an open circuit (at least at this voltage it is)

Good to hear your making progress. If you really want to find out what the problem is your going to have to follow the wiring between the two good points and see what's up.

Good Luck

Bob

Reply to
Bob Watkinson

"OceanTragic" wrote in message news:di847u$arg$ snipped-for-privacy@newsg3.svr.pol.co.uk...

Without the tester mentioned by a different Martin, if you're really curious you could try safely insulating one end of the duff cable, and then ....

1 Connect just L on duff cable to L on the good ring

2 Connect just N on duff cable to N on the good ring

If either of these causes a trip, it suggests that something has penetrated the cable and is causing leakage (presumably to a "natural" earth)

Then ...

3 Connect just L + E on duff cable to L + E on the good ring

4 Connect just N + E on duff cable to N + E on the good ring

5 Connect just L + N on duff cable to L + N on the good ring

One (or maybe 2) of these will probably cause a trip - so you may be able to narrow it down to which core is playing up.

I assume you haven't got access to much of the duff cable at either end - but if you have, then chop off a few inches from each end and retest. Unless the cable has been penetrated, you may well find the defect is very close to one end or the other.

HTH

Reply to
Martin

Original Martin here:

I agree with Bob and the new Martin.

At the stage you've reached, an insulation tester (500V) would merely confirm what you already know - your RCD is effectly your insulation tester. A tester could tell you whether the leakage is from L or N, but you still need to replace the cable so that'd be of passing interest only.

Martin's final point is worth noting: if the fault is not the result of a penetration of the cable (nail, dead rat's mouth bridging the conductors, cable resting on a hot source (> 70C).....) then the chances are that snag's in the last inch or so, and as you've decided to replace the cable anyway, if you have the slack, (big 'if') it's worthwile lopping off the end and seeing if that does it before ripping up the floors.

The replacement cable will be the same type (current rating) - 2.5mm sq twin and earth, I assume - and not some length of flexible cable you've found in the garage - that's a statement not a question!

Let us know what you found - there must be dozens of people as anxious as you are to know the cause of this snag.

Martin

Reply to
Martin (orig)

Reply to
Den Corfield

The guy's merely going to kill himself - I cannot see how that can possibly justify the use on a Newsgroup of the highly offensive expletive "oh dear!"... you really must keep your emotions and language under better control :-)

... but purely out of curiosity, could OceanTragic please let us know if he's still breathing...?

Reply to
Martin

Not only breathing, but have totally fixed the circuit problem.

Thanks to everyone who helped

Reply to
OceanTragic

Excellent news, Kev; well done.

Any idea what the cause of the problem was?

Reply to
Martin (orig)

Not really. I traced one end of duff wire further back...ripped up the floorboards... until it was just about to go back down the wall to the other end. I cut it, blocked it, and connected it back to the end of the radial..and it worked. Tried the other end that was literally just going down the wall to the other socket/radial and it failed. I didn't have enough cable to try chopping an inch or so off as it wouldn't move in the conduit that was buried in the wall, so I needed a different solution.

After mapping out the paths of the sockets/cables etc I realised that the only way to fix the duff cable was to tear the wall apart...and that just wasn't gonna happen - kitchen only decorated last year (and no I didn't touch the electrics then!). So I looked at the other options and realised that I had an option of routing the good end through a couple of beams that cables went through anyway and down behind the fridge/freezer to the socket that was just before the end of the second radial. A few tiles removed and plaster walls chased and job done. Still got a bit of tidying up to do but did all this and still got to watch the football on Saturday afternoon.

Reply to
OceanTragic

"OceanTragic" wrote in message news:dieesr$8md$ snipped-for-privacy@newsg4.svr.pol.co.uk...

good result. Well done!

Reply to
Bob Watkinson

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