Cable

[Sapper]

One for the Leckie lads. I need to run a cable direct from my consumer unit up to the loft across to the other side down the outside wall in suitable conduit and into a weather proof outside outlet with two sockets.
I will be getting the Electritian to do this but want to lay the cable myself. Question is, what size cable should I use?
Thanks for any help.

 

[ChaiLatte]

You need to clarify what you mean by 'two sockets'. If you mean a twin 13A socket outlet, 2.5mm^2 would be a starting point. You might mean two individual 32A blue industrial sockets, in which case the requirements will be different.

However, you should ask the electrician as other factors come into play (like overall length, whether the cable run is insulated, whether it is in conduit).

If it is a lot of work and you want to future-proof it (e.g. perhaps for a car charger), the extra-over cost of a reel of 4mm^2 cable today is minuiscule compared to buying and installing that same cable five years hence.

The challenge is that 4mm^2 twin and earth is a bit big to fit inside 20mm conduit (so you might have to put singles in the conduit and T&E elsewhere) and any twin and earth at all is not great in a conduit that is anything but straight.

So speak to the electrician after that electrician has been to site to look at your proposed route and actual sockets.

 

[Sideways]

Your electrician has to be responsible for "design, specification, installation and test".
Talk to him first. Explain what you want on the end of it and let him tell you what to buy and how to install it if he is amenable to you doing the labouring. He may or may not.

 

[Spectric]

That is one of my pet hates, people buy a roll of cable and think that it is rated at X amps without any consideration for the length of the cable run or means of fixing. Yes I have seen a shed wired with about 100 metres of 2.5 with lights and sockets that the guy is complaining about his small welder is playing up and had not even wonderd why the lights were diming so much.