Ok so I have about 8 plugs not working, after one of them blew a fuse. After a week of doing all the standard checks I can'tfind the problem, please help. I have checked;
- the fuse box/consumer unit, all wires and breakers are fine and have power and I changed a few wires around to double check.
- the failed plugs wiring is all fine and no lose wires, but still nothing live.
Any ideas please? thks Jono
On Monday 28 October 2013 21:43 marlowhaymaker wrote in uk.d-i-y:
You mean "sockets"?
Are these 8 *all* of the sockets on a single circuit/ring?
Or are there some that do work?
What was the fuse that blew - a plugtop fuse or one of the breakers?
Thks, answers as follows'
Are these 8 *all* of the sockets on a single circuit/ring? Answer: Yes I believe so as the sockets follow logically around a kitchen.
Or are there some that do work? Answer: There are some sockets in the area that do work but not 100% sure if they are on the same ring, but I am pretty sure the whole ring/circuit is not gone.
What was the fuse that blew - a plugtop fuse or one of the breakers? Answer: It was a plug fuse, and it blew because my missus used the hoover and pulled the cable so hard it broke the wire at the plug and tripped that way.
Any help on this appreciated. cheers Jono
I recall investigating a similar fault to the one you describe. In this case the fault had not only blown the fuse in the plug, but it had also caused the circuit breaker to trip. However after resetting the breaker, the circuit still seemed to be dead.
It turned out to be a faulty MCB that reset physically nicely, but only reset electrically about one time in four! So that would be a suspect in this case.
I am a little concerned by your comment about "I changed a few wires around to double check". Did you return them to their original places?
This should be an easy problem to track down if you have a multimeter and are prepared to carry out some tests. You will need to open the consumer unit though.
1) With the main switch off, turn on the MCB for the circuit and check that its input at the bottom, is electrically connected to its output on the top using a low ohms resistance range on the meter. So should get a reading of effectively zero ohms (or the same as with the probes pressed against each other). In not replace the MCB. 2) Again with the main switch off. If the circuit is wired as a ring, there should be a pair of live wires connected to top of the MCB, plus also a pair of earths and a pair of neutral wires as well (follow the wires to the MCB back to the cable sheath to find the others). If you disconnect the live wires from the MCB and measure the resistance between them, you should see near zero ohms. Repeat the tests for the neutrals and the earth wires. You could get much the same reading for all three - with perhaps a fraction of an ohm more on the earth wires since they are normally slightly thinner. If there is no connection or a high resistance (anything over say 3 ohms) connection between the pairs of wires. Then you probably have a loose connection in the circuit.We can give you more detail on tracking down a fault, if the above has not shown were it is.
Proteus wasn't it? You helped me when I had the same problem. I've finally retired all my Proteus stuff!
Well one of your assertions has to be wrong then. IE if you really did check all connections, then it would give power. It is possibly a tarnished aor carbonised piece inside a socket, if said socket is being usd to daisy chain the others. The first one you encounter is the prime suspect I'd suggest. Brian
Also of course, one can easily tell if the other sockets are on a different ring by tripping the other breakers as well, one at a time. I still suspect 'relaxed' wiring which has now carbonned something up or just come adrift. Proverbial straw and camels back. But if the sockets that are live are on a different ring then its more likely to be the breaker itself with such a violent short some of these can seemingly not last long.
Brian
Is there a chance that it has been wired as a fused spur and there is a fuse sitting in a cabinet / on a wall somewhere that has blown too?
Otherwise you will just have to find out where the break in the circuit is by working around it (with the power off! using a multimeter).
Philip
On Tuesday 29 October 2013 09:54 snipped-for-privacy@gmail.com wrote in uk.d-i-y:
That is a very good theory. Failing that, my money is on a non compliant daisy chain spur.
It could also be two faults on a ring causing an island of sockets in the middle. Note - one ring break could have been there a long time, unnoticed. The 2nd one would have manifested the symptoms.
Yup, that was the one... one of those cases where stuff was just not making sense.
Agreed.
The other potentially useful tool is a "volt stick" (used, of course, with the power on).
Also perhaps worth getting one of those "three lights" plugs to check for faults in all the other sockets. Plenty of both on eBay.
+1 nice clear simple instructions and safe for noobs because its all on a dead circuit too.
Thanks all, the MCB angle is worth looking at again, but I don't have a telemeter to measure the OHM difference. Is there an easier way to do that? I did change the wires across the board just to see if I can identify the source of the problem, so the breakers all look ok.
The daisy chain is probably not compliant, but that should not know out the plugs as such. I have gone through each socket and checked the wiring, and have not seen anything untowards, either loose wiring or anything carbonated or burnt.
I like to think I am diy savvy however the missus is getting impatient and wants it fixed. Any ideas before I call in the professionals and have to start paying?/
John Rumm;3140898 Wrote:
Well you need some basic test gear to get much further safely. A £15 multimeter from Maplin or similar would do fine for this, and you will find other uses for it later.
A plug in socket tester like:
(any electrical wholesaler / ebay etc)
will let you quickly and easily run down a row of sockets and see at which problems begin.
Something like:
makes plugging meter leads into a socket much simpler.
armed with a test lead extension:
Stage one is to positively identify which MCB should be feeding the sockets in question. Stage two check the MCB works and stage three work out where you have a connection fault.
1) Even if there is a disconnected wire, chances are not all three of them are disconnected - so you should be able to measure continuity between a non working socket and the consumer unit on at least one of the wires. So say you get a continuity reading between the neutral of the socket and the neutral bas bar of the (unpowered) CU. You can now with a bit of trial and error (disconnecting all the neutrals in turn) work out which cable has the matching live and hence which MCB is the right one.2) Once you know the MCB, testing it is either a case of of checking continuity between top and bottom - or with the power on, checking for live voltage at the top terminal.
One other thing you can check, and Tim hinted at this... the row of sockets may have been a "fused spur" (normally if you want to extend a ring circuit without continuing the ring, you add a spur. To protect the single run of cable, you either limit the number of sockets to one double, or you fit a fused connection unit, and then run multiple additional ones. If you have blown the fuse in a FCU that feeds a spur like this then that will also give the symptom you are seeing.
Thks John and everyone, all good stuff.
I am now looking for the FCU units as that may be the problem. I think I may have to get an electrician in to test the MCP in terms of OHM different, as correct me if I am wrong but that sounds like a specialised and potentially dangerous job. The cheaper telemeters may not do this easily and I would assume an electrician would have something industrial scale that could do it more effectively. Again it is against my religion to call in a the experts as I do most of my own DIY, but in this case I maynot have an option.
snipped-for-privacy@gmail.com;3140867 Wrote:
In message , marlowhaymaker writes
John Rumm gave details in one of his earlier posts. You do the tests with the main switch in the consumer unit turned off, so it is quite safe.
A basic multimeter will do fine, measuring resistance is abasic function., I broke my normal one and used one out of a kids electronics kit the other day :-) £10 or less will get you something suitable.
For these tests, not really.
It's quite doable, and you will get plenty of advice here on what to test and how. But as ever, you shouldn't do a job if you don't feel confident doing it.
A cheap multimeter will measure the end to end resistance of a ring circuit with both ends disconnected at the CU. It doesn't need a high degree of accuracy - it will be pretty obvious whether or not you have a discontinuity or high resistance. As far as the MCB is concerned, you can remove it from the CU to test it if that makes you feel happier. There shouldn't be any measurable (with a cheap meter) resistance between its input and output in the ON position.
Having said all that, if there's anything you don't feel 100% confident about, it's far safer to send for an electrician. I would hate to be responsible for encouraging you to electrocute yourself!
Look for things like:
Well ok since you asked, your wrong ;-)
The procedure I described is very simple and safe since it does as much as possible with the power turned off at the main switch. So long as you avoid poking metal objects into the incoming wires of the main switch (usually the top contacts on the main switch) there is nothing else live in the CU.
As for resistance (aka ohms) readings - all you are really looking for here is a go / nogo type of reading. So any basic multimeter will do the job.
For example:
I'm all for diy, but in all honesty I think encouraging you to do the job with your present level of skill would be somewhat dangerous.
NT
And he's not explained what a plug socket is. Is it a plug or is it a socket?
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