Use shower cable for wall socket instead?

[Sprogginz]

I noticed a very thick cable curled up in my loft that runs downstairs. I assumed it was put there just in case the new owner (me) wanted to have an electric shower installed.

Just to test, I put a non-contact voltage pen next to it and to my surprise it lit up like a Christmas tree! I've since turned it off from the fuse box.

I don't want to install a shower but can I use this cable to install a double wall socket instead or is it dangerous/illegal?

It really would save me a lot of grief, otherwise I'd have to use a bloomin' extension cable everytime I want to use a fan/heater or extra light up there.

Thanks very much.

 

[flyingsparks]

Where do you want the socket? In the loft? Yes you can use a 6mm cable for a socket supply. It must be protected by a 30mA RCD. You may want a 35 or 47mm deep back box in order to get the cables in to the socket and the socket screwed back nicely.

 

[Sprogginz]

Where do you want the socket? In the loft? Yes you can use a 6mm cable for a socket supply. It must be protected by a 30mA RCD. You may want a 35 or 47mm deep back box in order to get the cables in to the socket and the socket screwed back nicely.

I'm assuming this is okay?

Hope so, and thanks for the tip on the back box!

 

[flyingsparks]

Looks ok. Providing the socket turns off when the yellow test button on that rcd is pressed your ok.

 

[flyingsparks]

I have assumed it's a 6mm cable for some reason but actually it could well be a 10mm. If it is you may struggle getting the cable into the terminals on he socket. Have you got a photo of the cable?

 

[Sprogginz]

Here you go:


Actually, I'm now totally confused using the voltage checker pen because I'm fidning this absolutely bizarre!

I'll try not to do the same to you so here goes:

With the shower CB off, the cable still lights up!
With the upstairs lights CB also off, the cable does not light up.
With the upstairs lights off but the shower CB on, the cable lights up.

I have got no idea what's going on here.

Also just add to the confusion, I assumed the two cables at the back were part of the lighting circuit. When I switch the landing (2-way switch circuit) light on, the cable furthest to the wall lights up. The one next to it already lights up. HOWEVER, when I switch the upstairs lighting CB off, that cable that I mentioned last still lights up with the pen! No ligths come on by the way.

Totally messed up to me but hopefully makes sense to someone else.

###UPDATE###
Just realised, the small cable that still lights up belongs to the smoker detector CB!
The mystery of the big cable still exists though!

 

[DetlefSchmitz]

Trying to draw any useful conclusions from the 'tool' you are using is a waste of time.
You need a 2-pole voltage detector connected to the l and n of the cable to make any sense. Anything less is pointless.

 

[flyingsparks]

Your picking up small voltages which are being induced into the cable from other cables it lies next to along its route. Called capacitive coupling. This is a prime reason why voltage pens are not an accurate form of measurement.

 

[Echo the husky]

A good guide for the cable size, if the earth wire is 1 solid core it will be 6.0mm² if the earth wire is made of several strands it is 10.0mm² (or bigger!).
Looking at the photo I'm going to guess 10mm.

 

[333rocky333]

Not sure if T+E cable has it but sometimes the size is embossed on the grey sheafing

 

[Taylortwocities]

Guide to sizes in the WIKI

//www.diynot.com/wiki/Electrics:flatpvccables

 

[Sprogginz]

Thanks for all your help guys.

I didn't realise the pens were that unrealiable and it was easy to pick-up voltage signals from other cables. To be safe I just turned everything off and used a head-lamp torch!

It's installed and working now. The cable is a big bugger and I certainly needed a deep pattress!

Thanks again.

 

[alexjgoldie]

Looks like 10mm, but yes the cable often has the size embossed on it. Also you would have a 13amp socket protected by a 40amp MCB. Have you considered installing a small consumer unit on the end of this cable, then you could supply other things in the future?

 

[Iggifer]

Have you considered installing a small consumer unit on the end of this cable, then you could supply other things in the future?

No point doing that until it's needed tbf. If the OP just needs a socket up there, he's good to go.

 

[EFLImpudence]

Also you would have a 13amp socket protected by a 40amp MCB.

No you wouldn't; it is protected by the fuse(s) in the plug(s).