Burning cable, what should i do??

[ban-all-sheds]

i know 10mm cable is a pain to fit and bend and do anything with...

Won't be long before the relentless shower power wars mean that people start needing 16mm²

For shower pullcords, if you can position it so that there is free space above, and dress the cables so that when you screw the switch in place the cables get pushed up into the loft or floor void, rather than needing to be curled up, 10mm² isn't too bad....

 

[plugwash]

yeah the wire and screw to backbox system doesn't work too brilliantly for larger cables

thats why most higher power kit (things like CUs meters switchfuses distribution boards large isolators etc) uses the wire and screw on cover system (so you aren't moving any wires when you open and close them).

 

[Steve]

Why cant they make recessed shower switches that mount on the back of the ceiling and therefore can have bigger wiring boxes on the back etc. This would also be more aesthetically pleasing!

Just like a little circle of plastic visible, halogen downlight-sized, with the cord and light! sorted!

 

[ban-all-sheds]

My shower switch:

My light switch:

 

[plugwash]

are those on dryline boxes or something more substantial?

 

[ban-all-sheds]

The shower switch is on a metal back-box fixed to wood which is in turn fixed to a joist.

The "light switch" is actually just a blanking plate - above it, fixed to a piece of wood which is etc etc, is a regular round surface pullcord switch.

 

[thePhilster]

Hi,

I've had the same problem recently with a Triton Ivory 9kw shower. I replaced the pull cord a few months back, and the smell went away. But I've noticed it recently.

I've checked the size of the cable and it definitely looks like 10mm, so is it possible that the melting plastic is due to loose connections in the pull cord box? We don't have an extractor fan in the bathroom, though we do keep the window open for ventilation: but could condensation be causing the current to arc??

Any help gratefully received...

Phil

 

[Damocles]

Thick cables are harder to screw down tight. If the strands have space left between them they can bend to shape after you fitted them and get loose. Or you might move some of them as you push the whole switch together and again pull them loose.

 

[ban-all-sheds]

I've checked the size of the cable and it definitely looks like 10mm

Hope this doesn't offend, but... when you say it looks like 10mm, how have you arrived at that conclusion?

 

[thePhilster]

I've checked the size of the cable and it definitely looks like 10mm

Hope this doesn't offend, but... when you say it looks like 10mm, how have you arrived at that conclusion?

It measured 17mm across and 10mm in thickness... Think that was the measurement of 10mm cable I saw somewhere. And, no offense taken!!

 

[thePhilster]

Thick cables are harder to screw down tight. If the strands have space left between them they can bend to shape after you fitted them and get loose. Or you might move some of them as you push the whole switch together and again pull them loose.

Thanks for that. It was a bit of a struggle getting the cover to screw back on once I'd rewired... Wouldn't surprise me if what you'd mentioned is exactly what's happened...

Any expert tips on how to work with such thick cables??

 

[mapj1]

1) Once assembled, and with cables formed to final shape, push the box cover on, thus straing the wires as they will be in final install, then remove as little as possible to alow you to recheck that the contacts are still tight.

2) Use a bigger back box than the minimum, and take a little time to lay the cables so there are no violent kinks or twists. Remeber that dry lining boxes, or even metal back boxes can be sunk into the ceiling with suitable reinforcement for pull swithes.

3) allow for the bend radius - its larger than you think

4) try and leave enough slack for a remake. Whoever follows you will appreciate it.

 

[ban-all-sheds]

I found the technique I listed above worked a treat - assuming you have access to set it up, have the cables going straight down through the back of the box, arranged so that when you put the switch in place the cables just push upwards into the loft or ceiling void, and don't need to bend inside the box at all.

 

[thePhilster]

Okay, so the cables have melted a little at the end, and the cable from the shower is VERY short, and I don't think there's an awful lot of room for manouvre.

Can I extend this cable by using a junction box or something, or do I have to totally replace the cable from the shower to the pull cord? The guy in B&Q didn't think you could extend the cable.

Any firm answers to this question??

TIA
Phil

 

[plugwash]

you can extend the cable you just need something suitable to join it with

something like

http://www.tlc-direct.co.uk/Images/Products/size_3/AAJB60.JPG