Electrical question - washine machine plug seized in socket

shandypants5

This is how a good circuit should be.

The white blocks are sockets.

shandypants5

This one is bad, and a tee shape spur is really bad.




Try to find where all the wires go. just so you know you wont melt the next plug again.

JimmyTheWig

Thanks, ShadyPants. Great diagrams. All makes perfect sense.
Yes, it is three cables.


Three questions...

1. How do I find out where the wires go? Is it an electrical question (e.g. measing potentials) or a physical question (e.g. foloowing them under floorboards, etc).

2. I've taken this socket out and the nine wires are now lose. I've turned the power back on. (Don't worry, the wires are safely behind a washing machine, so it's not dangerous!) Nothing else in the house seems to be not working. Does this prove that it is not part of a ring, as if it was a ring then the ring would be broken and everything else on the ring wouldn't have power? And does it suggest that it is not feeding two (used) spurs as the spurs wouldn't have power? From this evidence I'm almost suggesting that it is a spur and the other two cables are doing nothing! Can I test this with a multimeter (being careful with live electricity, of course)?

3. If I continue with my plan of taking the socket up the wall with a junction box and a single cable, will this make things any worse? i.e. is this sort of creating an extra spur, or does it not really make any difference?


Thanks again,
Jim

andor

You've got me wondering here. I am replacing all of my sockets with brass ones, one at a time when I have the time. Now, like you, I have taken off a socket, inserted the cable ends into terminal blocks and on switching the power back on, find that all of the other sockets are still working. From this experience I have guessed that the ring can be broken since all other sockets are still connected to the power supply. Am I right?

andor

shandypants5 wrote: »

it may be a single live coming in and feeding 2 more spurs to 2 more sockets.

If this is the case, with the power switched on and the ends of the cables disconnected, (as they are), one cable positive would be live and the other two cable positives, dead. This would be very easy to test.

andrew-b

If it wired correctly and there are 3 cables (live,neutral,earth in each) then it should to be a socket wired into a ring main with a spur off it to another socket. However, if it's been wired wrongly it could also be a spur itself with two spurs off it.

I would turn off the power, open up the dodgy socket, look which direction the cables go off at and open up other sockets that look likely to be connected upto it. With any luck one nearby socket will have a single cable going into it (a spur off the dodgy socket) and the others will all be part of the ring main with 2 cables each. If it looks like more than one connected socket is a spur then that could be a problem.

If your moving the socket i believe it comes under the realms of Part P notification (certainly if its in the kitchen) and with 3 cables in there it might not be straightforward - depends on the cable routes and how much slack cable is going spare. I know it may not seem the safest place to have a socket but if i were you i'd only move it if there is definitely a problem with water getting into it. If water drips down on it and causes a short circuit any RCD protection on the circuit should kick in anyway.

All things considered i think you might be better off to get an electrician in to verify it's wired up correctly and reposition if preferred. If it isn't wired correctly it may be worth getting the electrics in the whole house tested for peace of mind.

As always with electrics...if in doubt get someone in.

Andy

WestonDave

Of course the ring can be broken - whether it can be broken safely is another matter. If you break the ring, you get two chains a bit like the two spurs in the diagram in post 23, except that potentially you could have all your downstairs sockets bar the one you have decommissioned all in one line (if you happen to take out the socket nearest the supply on one end of the ring!). Now if two sockets in a chain spur is dangerous, think what ten in a chain could be.

Guys - put some socket fronts on to recreate the ring when you are not working on the circuit, or at the very least be extremely careful what appliances you use simultaneously otherwise you are risking a fire. I really don't understand why if you are taking a socket front off to replace it with a brass one, why its worth spending the time putting the cables into terminal blocks rather than just putting the new front on?

Jimmy before you put it back together you need to find your non working socket - that third cable must be feeding something and it shouldn't be working right now. Given that you can't find anything not working its unlikely that you have a complex spur system so you should just have two ring wires and one outgoing spur. The issue is that if there is no socket not working (check other things like the cooker socket, extractor fans, sockets in cupboards etc) then there may be a live wire just plastered into a wall somewhere when someone took out a socket. You really don't want to find that next time you are drilling!

ic

shandypants5 wrote: »

This is how a good circuit should be.

The white blocks are sockets.

Shouldn't there be a 13A fuse on the ring from the which the spur spans? After all you're going from 2 x 2.5mm2 cable to just one, so the cable needs protecting?

andrew-b

ic wrote: »

Shouldn't there be a 13A fuse on the ring from the which the spur spans? After all you're going from 2 x 2.5mm2 cable to just one, so the cable needs protecting?

I don't see why there should be a need for it. If the spur is a FCU (fused connection unit) for something like say a cooker hood it will have a fuse in it anyway. And if it's just a socket it'll have a fuse in the plug of whatever is connected. So if the wiring is done correctly (with a maximum of one spur per ring main socket) then there's no need for it. There may of course be some new regulation i'm not aware of..maybe someone more knowledgeable of the regs could comment?

Andy

JimmyTheWig

andrew-b wrote: »

If it wired correctly and there are 3 cables (live,neutral,earth in each) then it should to be a socket wired into a ring main with a spur off it to another socket.

Of course. I didn't think of that.

If your moving the socket i believe it comes under the realms of Part P notification (certainly if its in the kitchen)

I believe that is only for the kitchen. But...

All things considered i think you might be better off to get an electrician in to verify it's wired up correctly and reposition if preferred. If it isn't wired correctly it may be worth getting the electrics in the whole house tested for peace of mind.

I think you might be right.
Anyone got any idea how much we'd be looking at for an electrician to (a) verify it's wired up correctly and reposition the socket, (b) test the whole house, and (c) rewire the whole house.

Anyone know any reliable electricians in the Chessington (Kingston) area?