Whats going on here? Neutral burnt with photos

[martinxxxxxx]

I suspected a loose connection, but no loose connections were found

 

[DetlefSchmitz]

Well, there's loose and there's high resistance. You might have, for example, a really tight clamp on a piece of insulation.

 

[PrinceofDarkness]

The problem with loose connections, Martin, particularly of the chronically damp type such this ^, is that the originally loose connection becomes so bad that it 'welds' itself to the terminal, thus 'appearing' to be sound - when in fact it's anything but, in terms of conductivity.

If you suspect something more sinister than a local bad joint, you ought to check the condition of the other sockets in that line.


Lucia.

 

[tonyelectric]

Totally agree with princeofdarkness comments, i've seen a couple like this this year, normally on slightly damp walls (the mount box is often corroded indicating the presence of a dampness), when you have cut it off and replaced it you will almost certainly find the copper has fused in the terminal and the screw may even have welded in.

The other possibility is that the shoe that makes contact with the plug pin is making a poor connection and the heat is conducting back to the terminal, but this would almost always discolour the faceplate / damage the plug.

 

[martinxxxxxx]

I turned off this circuit last night, will go back look at all of sockets inside. Plus a full FRC test as per the IEC.

I think as the socket was hot; as was the extension lead plugged into it (into that was plugged a hairdryer), which had not been used according to the students for a couple of hours; That the socket must be so carbonised that it continued to conduct even with no power being drawn from it. Another red herring is that heating system has been down over night, so I did inquire if the girl had been using the hair dry to heat her room by any chance. I know even if she had it should not on it's own led to the problem.

Thanks for your comments

Martin

 

[SgtTrojan]

............and have you seen the age of those sockets? Heavy load, mucky socket contacts, high resistance, increase in heat, transfer of heat to conductors.

 

[martinxxxxxx]

Yes I think you are correct. I think it is an extended use of a few amps on a socket that is worn out that has caused the problem.

I will be chopping the wall away this morning after looking at the other sockets. I the whole lot need s rewiring I will have to talk to the client further before doing anything.

Martin

 

[ban-all-sheds]

Well, there's loose and there's high resistance. You might have, for example, a really tight clamp on a piece of insulation.

Or you might have a socket which the previous occupant fitted to damaged cables.

 

[martinxxxxxx]

Have had a really slow morning, have been completely snowed under (literally) But I have been back and had another look, for your delectation here are some more photos.

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• martinxxxxxx
• 2 Dec 2010
• 1

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• martinxxxxxx
• 2 Dec 2010
• 1

If you look carefully and I know you all do; you see that there is a shiny bit on each of the neutrals. On further questioning of the student. I asked what excactly was plugged in at the time, she replied everything and I said would this include a fan heater. er yes.

Cable further down the wall looks undamaged.

Martin

 

[bernardgreen]

Offer to check the plug(s) that plugged into that socket.

They might be in need of replacement as well

 

[ban-all-sheds]

No RCD on that circuit?

 

[martinxxxxxx]

I have had a look the plug in question, which is part of a cheap looking four way socket. No burning noticed but has been discarded as a precaution anyway, probably only an item from poundmart in any case.
No RCD, old wylex fuseboard and no continuity on the ring. leg "A" goes to all the sockets in the kitchen and has lack of continuity to the next socket in the hallway which connected to all of the other downstairs sockets and to leg B.

Martin

 

[PrinceofDarkness]

What a can of worms you seem to have opened, Martin.......

Lucia.

 

[martinxxxxxx]

Always the bloomin way around here with the bodger kitchen fitters on the loose. But I won't connect it back until it can be signed off on an EIC anyway.

 

[PrinceofDarkness]

Oh for goodness' sake Martin! Signing off on an EIC?

Don't be so daft! Cut that box back 'til you reveal useable cable, then fit a relocated box and socket outlet ( and get yourself some bonding plaster!).

Lucia.