Power to Outbuilding/shed

[Roxsta]

Hi,
I was wondering how to calculate the size of SWA cable to use for an out Building.I mean the cable coming off of the CU from the house.It is going to have a shower, 3kw oversink water heater,1 Lighting curcuit and 6 sockets Either a Ring main or radial curcuit (what is reccomended?)
I want to know the sizes of mcb's to use for the shower and Water heater curcuits aswell.
I know this has to be protected by an RCD because it is outside the house.
Thanks

 

[Steve]

Bloody funny outbuilding that. Most people settle for a socket and a light, maybe a cold water supply, at a luxury. This sounds like a residential development.

There is no straight answer when designing such a submain.

We need to know:

What will it be used for? How far from the house, cable run wise? What major appliances in the house? Main fuse rating if known. Photograph of the consumer unit and the mains intake area / meter cupboard.

The answers to these will determine whether it will be cheaper for you to get a new supply for the outbuilding.

If you dont know any of these, or now dont feel confident to do the work, get an electrician in.