Outdoor Power

[Octavius]

I am intending to lay some armoured cable along the length of my 100ft garden (in a 2ft deep trench with cable warning strip 6 inches above etc). My intention is to provide a connection from my main Consumer Unit to an additional small CU in a brick built shed, with a lighting circuit and 2 ring mains. Don't worry I will be consulting a qualified sparks soon, but my question is � am I along the right lines? I know armoured cable needs to be converted with glands and blank box to normal cable before entering the CU's but does anyone know where I can find some general guidance in the meantime?

[raysparx]

Hello Octavius,

Have a word with the sparks first,any outdoor work or work in kitchens,bathrooms etc, have to be notified to local council, if you intend to do work yourself get onto building control at the council,before you start, if you don't comply the outcome can be very serious, any Electrician doing the work will have to be Part P registered, you probably think I am winding you up but PLEASE check it out,

[buildersmate]

As Raysparx says, this work must be to Building Regs Part P. This either means that the Spark must be Part P registered so he can self-check the standard of his work or you must apply for Building Regs approval for the installation - which will involve a separate fee and an inspection of the work. Note that if you follow this latter route, in theory you could undertake the work yourself. You are on the right lines. Can't find you a useful enough website for guidance on outdoor installations. The most pressing thing you must consider is to protect this external circuit by an RCD.

[Sparkyboy]

Hi

You are going about this in the right manner but you may be being a little ambitious trying to have a lighting circuit and 2 ringmains in your shed.Why do you need 2? A lighting circuit of 6amps and 2 ring mains of 32amps each combined with the voltage drop over 100ft will necessitate a very large size of armoured cable which is not cheap and I doubt if you will find a MCB for your house CU large enough to protect the cable. Also you run the risk of blowing your main incoming fuse at times of high consumption. I would suggest you stick to a lighting circuit and 1 ringmain in your shed for which you will probably need 10mm SWA fed through a 45amp MCB in your main board. You should be able to terminate the SWA directly into both CUs by means of glands.

[stanleyman]

You'll need to follow the advice already given but to answer your last part try here.

http://www.tlc-direct.co.uk/Main_Index/Cable_Index/Armoured_SWA/index.html

[Octavius]

Hi, thanks for all your answers, rest assured I was aware of Part P and I am going to employ the use of a qualified electrician. The reason I was saying 2 ring mains was because I thought of 1 for power within the shed (I dunno maybe small power tools, or a kettle and a radio etc) and then one for outside power for say lights to the garden, a pond pump or for the lawnmower. I was also aware that external power needs RCD's and it isn't intended that all sockets would be in use at the same time.

I think I am going along the right lines but I was just sounding out my theory as I have found some conflicting advice. Cheers for the A's.

[raysparx]

Hi Octavius,

You are on the right lines, I wouldn't put two ring mains in ,garden lights won't take much you might be better to put a couple of radial circuits in on 20 amp mcbs, if you go for the ring mains it obviously will require a bigger cable, and that can cost a fortune, but glad you are doing it the right way.

Good luck, Ray