Electrical wiring gets hot

[Mr_love_monkey]

For our electric shower, we have in a cupboard, one of those chunky red cooker switches (double pole, 45amps) for turning the power on and off to it.

Recently I noticed that the cable leading into and out of the switch was getting hot, and the switch itself (which is mounted on the wall, not buried in the wall) was also getting hot.

All of a sudden the switch stopped working, in as much as it would switch on. so I opened it up, and replaced it with a new (similar one) - however, some of the plastic covering from the wires has melted from the heat produced from the wiring, and it seems to have been the heat that stopped the switch working, as I think something melted.

what's caused this? - how can I stop it happening again, as the cable still seems to be getting hot.

Ta

[Hugh]

May I recommend getting an electrician in (and no, this is not a metaphor, like "painters").

You don't want to be messin' about with overheating leccy stuff (imho).

[Mr_love_monkey]

Originally Posted by foreverwar

May I recommend getting an electrician in (and no, this is not a metaphor, like "painters").

You don't want to be messin' about with overheating leccy stuff (imho).

yeah, that's what I think as well, I'd just rather have an idea of what could be behind this, rather than having someone blind me with science...

[Raistlin]

Ok, it sounds like the shower is pulling more current than the cable in use is actually rated to handle (wrong sort of cable installed originally). This could also be caused by a fault with the shower unit causing it to draw too much current (right cable, faulty shower). To be honest, the whole circuit should be independently fused and that should have blown before the plastic/switch melted (wrong or no fuse on the shower circuit).

Either way, that's why the plastic is melting, it's almost certainly why the switch stopped working, and it's the sort of thing that leads to electrical fires and people dying.

In my opinion the best thing that you can do is get an electrician in to look at it, messing with this sort of thing yourself (unless you really know what you're doing) is seriously dangerous - we really don't want to lose the MLM love

Not to mention of course that it's probably not legal under the new regulations for you to do that work yourself.

Don't use the shower. Get an electrician in to sort it out. Do it now!

[abailey152]

It sounds like the DP Switch has started to fail, causing high resistance and getting hot. This heat has, in turn, been conducted down the wiring.

The problem is that copper wire can degrade if it has got too hot, so I'd recommend getting an electrician to check everything out, just to be sure.

[Mr_love_monkey]

Originally Posted by Rob M

Ok, it sounds like the shower is pulling more current than the cable in use is actually rated to handle (wrong sort of cable installed originally).
This could also be caused by a fault with the shower unit causing it to draw too much current (right cable, faulty shower).

Hmmm.... that is probably is it - it's only started recently, and the shower has been playing up recently, i.e. water getting too hot - so that sounds like it.

Originally Posted by Rob M

To be honest, the whole circuit should be independently fused and that should have blown before the plastic/switch melted (wrong or no fuse on the shower circuit).

It is on it's own circuit - but I don't have much faith in the people who installed it - so I'm expecting something is wrong at the fuse box too.

Originally Posted by Rob M

Don't use the shower. Get an electrician in to sort it out. Do it now!

Yeah, I've had it turned off at the fusebox since I replaced it, as it was still getting hot - didn't want to take the risk.
I could probably replace the shower myself - but I think an electrician might be the best plan...

---------- Post added at 09:27 ---------- Previous post was at 09:27 ----------

Originally Posted by abailey152

It sounds like the DP Switch has started to fail, causing high resistance and getting hot. This heat has, in turn, been conducted down the wiring.

But it happens with the new one as well?

[PeteTheMusicGuy]

Its sounds like you need to get somone out Mr LM and as Rob said it may be safer not to use the shower until you get it checked

[Graham M]

It could be a loose Live/Neutral somewhere causing a high resistance and causing everything to warm up, but as has been suggested, where water+leccy are involved I'd definitely get the professionals in! (And no not the cheesey 70s TV show)

[Hugh]

l_m, have you been upsetting your wife lately?

You know, something that may cause her to rehearse the lines "Officer, my husband was in the shower, and suddenly there were lots of sparks and he started screaming - I didn't take any notice at first, as he is a bit of an attention seeker, but when I heard the flames crackling, I realised something wasn't it right"?

[Raistlin]

Originally Posted by Mr_love_monkey

But it happens with the new one as well?

If it's doing it with the new one as well then I'm guessing that either:

a) the original fault was with the switch, but the excess heat has now caused a problem somewhere else which also needs fixing, or

b) the original fault wasn't with the switch.

[Osem]

Is the installation (or any part of it) new? Have you recently replaced the shower for example? These instant electric showers can be over 10kw and require the correct type of wiring. IIRC 10mm FTE and a separate feed from the fuse box are required but you should obviously get all that checked by a competent person ASAP and before using it again. Finally, could there be a fault with the shower's heating unit? A few years back our immersion heater control switch melted due, I was told, to severe corrosion of the heater element which had started to fail.

[abailey152]

Turn it off at the consumers unit, and call an electrician. It needs to be thoroughly checked out.

[Mr_love_monkey]

Originally Posted by Rob M

If it's doing it with the new one as well then I'm guessing that either:

a) the original fault was with the switch, but the excess heat has now caused a problem somewhere else which also needs fixing, or

b) the original fault wasn't with the switch.

yeah, I agree - as I say, the shower has been playing up, with the water getting too hot, so it sounds like it's pulling more than it should.

In the process of sorting out a sparky now...

[Raistlin]

Don't know any good sparkies down 'London way' sorry, can get your plumbing sorted for you though if it needs doing

[Hugh]

Noooooooooooooo................................