Why is the cable going to the shower melting?

[holman210]

Hello

My brother has had his shower moved when he had the bathroom refitted. Recently the shower had been cutting out, loosing all power then sometimes coming back on by itself. I took a look and it looks like the ceiling pull switch was to blame because if you held the cord tight but not clicking it fully the shower came back on and the power light flickered.

I bought a new switch and proceed to undo the screws. When I took the switch away from its housing the Neutral FEED cable going to the shower was black and slightly melted. (See Image)

Also there’s 3 earth cables for some reason, the 3rd additional earth cable which I think the guy who did the bathroom added has clipped some of the core away to fit in the switch. Only problem is I cant find a switch that will accept all these earth cables. Im also concerned about the melting wiring.

Any thoughts?? Thank you!

 

[Alarm]

Far better will be along but, the neutral was clamped onto the insulation not the conductor. Probably causing the overheating (But there are other factors)
The CPC ( Earth) needs cutting back and fitted correctly.

If your unsure as you are asking I would get this checked out by a qualified electrician.

 

[ColJack]

the screw was loose, causing the switch to overheat and melt the cabe and probably weld the contacts ( which is my reason for saying that the shower switch should be for maintenance and / or emergency switching off only.. but others don't agree with that and will no doubt say so shortly.. )

as for the 3rd larger earth, this wouldn't be a council property would it? they do like to run in an extra earth for some reason, but I'm pretty sure it's supposed to go straight to the shower, not stop at the switch..

new wiring and someone decent to put it in should be sought ( you may be able to salvage the wire but without being there to see what slack you've got to be able to cut it back I don't know.. )

 

[ban-all-sheds]

Far better will be along but, the neutral was clamped onto the insulation not the conductor.

No - it wouldn't have gone in far enough. Just not tight enough. (Why is it always the N? )

The CPC ( Earth) needs cutting back and fitted correctly.

Yes to what needs to be done, but as it's a single it's probably a supplementary bonding conductor, not a cpc.

Why it's so big, IHNI, but it ought to go in OK. Clearly the bathroom refit was done by Numpty Bathrooms plc.


holman - you must cut the overheated cable back past any damaged insulation and past any discoloured copper, or it'll just happen again.

Make sure the terminal screws are nice and tight, then check them again the following day, and again a week later.

 

[ban-all-sheds]

which is my reason for saying that the shower switch should be for maintenance and / or emergency switching off only.. but others don't agree with that and will no doubt say so shortly..

Well...

If you don't switch it under load what will the problem be?

My shower switch also works the fan so it's used every time (with the shower turned off at its controls) - it's been in for 7 years, so will have been used literally (and I mean that word literally) thousands of times with no issues.

 

[PrenticeBoyofDerry]

The conductor could have well been loose causing the intermittent on/off of the power, this could also have been responsible for the insulation to burn/melt.
You need to cut the cable back to clean copper and refit it. Also check that the pull cord switch has not been damaged be the heat, if it has replace that also.
The extra CPC is likely to be a supplementary bonding conductor.

 

[Taylortwocities]

(Why is it always the N? )

.

Yeah, brainboxes, why is that then?

 

[ban-all-sheds]

The conductor could have well been loose

Just not tight enough.

You need to cut the cable back to clean copper and refit it.

holman - you must cut the overheated cable back past any damaged insulation and past any discoloured copper, or it'll just happen again.

Also check that the pull cord switch has not been damaged be the heat, if it has replace that also.

I bought a new switch...

The extra CPC is likely to be a supplementary bonding conductor.

it's probably a supplementary bonding conductor, not a cpc.

 

[ColJack]

which is my reason for saying that the shower switch should be for maintenance and / or emergency switching off only.. but others don't agree with that and will no doubt say so shortly..

Well...

If you don't switch it under load what will the problem be?

(See, told you )...
You and I know that, but the general populace is quite apt to set the controls to the temp they like and then use the pullcord as an on/off switch..
If they wish to do that, then an isolator in a cupboard and a contactor driven by a small pullcord would be a much better option..

My shower switch also works the fan so it's used every time (with the shower turned off at its controls) - it's been in for 7 years, so will have been used literally (and I mean that word literally) thousands of times with no issues.

If you bought a decent switch then there may never be an issue, but switches do have an operational lifetime..

 

[ricicle]

(Why is it always the N? )

.

Yeah, brainboxes, why is that then?

Hasn't it been established that the only cause can be that people pay more attention to tightening the L than the N ?

 

[PrenticeBoyofDerry]

The conductor could have well been loose

Just not tight enough.

You need to cut the cable back to clean copper and refit it.

holman - you must cut the overheated cable back past any damaged insulation and past any discoloured copper, or it'll just happen again.

Also check that the pull cord switch has not been damaged be the heat, if it has replace that also.

I bought a new switch...

The extra CPC is likely to be a supplementary bonding conductor.

it's probably a supplementary bonding conductor, not a cpc.

My PC has gone it to time lapse, it delayed on submitting. was not repeating your post as I had not seen it.
As for replacing the switch, was making sure that the op did in fact change the switch if damaged, the reason why the op original bought the replacement switch was that they thought it was a faulty switch rather than a loose connection and if the switch was not damaged, they can get there money back.
Hope you are no longer confused!

 

[holman210]

as for the 3rd larger earth, this wouldn't be a council property would it? they do like to run in an extra earth for some reason, but I'm pretty sure it's supposed to go straight to the shower, not stop at the switch..

Well it was, but this new thick earth cable was the one the fitter put in! The worrying thing is he put in a higher rated shower, 7.5kw to 10.5kw and moved the shower from one end of the room to the other. As far as we can tell he never ran this new earth to the consumer box so god knows where its screwed to. The screw didnt seem loose when I un screwed it although it was in there deep, had trouble getting it out, so maybe it was screwed into the insulation!

We had another look today to try and see where that earth goes, thats what’s worrying me about doing it myself. So, I’ve told him to call an electrician in.

Thanks for your advice guys! Forgot how good this website was for responses!

Thanks

 

[crystal ball]

I would like to see two screws on terminals for 6mm and over, one screw is not enough when the switch is pushed back onto the box, the core can easily work loose, this is the reason I never fitted an isolator on my shower

 

[ban-all-sheds]

My PC has gone it to time lapse, it delayed on submitting. was not repeating your post as I had not seen it.

Fairy nuff.

 

[ban-all-sheds]

My brother has had his shower moved when he had the bathroom refitted.

...he put in a higher rated shower, 7.5kw to 10.5kw and moved the shower from one end of the room to the other.

Very significant difference between the two.

What size is the cable? What rating is the MCB?

As far as we can tell he never ran this new earth to the consumer box so god knows where its screwed to.

It's a supplementary bonding conductor, not an earth, and it shouldn't go back to the CU, it should go to the pipes in the bathroom.

So, I’ve told him to call an electrician in.

Probably the best idea.