Loft electrics: run a cable outside?

[Sponge]

I'm in the planning stages of flooring my loft for extra storage space (it will not be used on a regular basis) and I also plan to add lights and a couple of power sockets (just in case). I was going to extend the ring main from inbetween two sockets on the 1st floor, but then had a thought...


Would it be better to have the loft on it's own circuit by running a dedicated cable direct from the Consumer Unit? Which leads me to the crux of my question: To avoid the time and effort of doing it internally, could I run the cable from the CU (which is on an outside wall) through the wall, up the outside of the house and then into the loft? If so, would I have to protect the cable in any particular way?

Thanks in advance.

 

[plugwash]

if you can find a supplier locally that doesn't charge too much get some 4mm split concentric, its easy to terminate (unlike swa) and suitable for direct use outdoors.

http://www.meteorelectrical.com/catalog/898 is the only supplier i found online but i belive many wholesalers will either have it in stock or be able to get it in.

 

[didthathurt]

I would say split con is a bt of overkill here. You can do this, make sure the holes through the wall are drilled a fraction lower at the external leaf then the internal, helps prevent water ingress. I'd use Hi-tuf like this
http://www.tlc-direct.co.uk/Main_Index/Cable_Index/Hi-Tuf/index.html
You could create a 20A radial, using 2.5mm cable, for the sockets and a fused spur for the lights. How you connect it depends on the CU layout, but you could get away without RCD protection for this (tho, if you want it and have no room in a split board on the RCD protected side, use an RCBO).