Outdoor power supply to household power supply

If you need more power than that, then you may need to approach your electricity supplier about providing a dedicated supply to your outbuilding. To estimate the total power requirement, think of the likely activities, and what equipment will be involved. What devices could you conceivable need to use at the same time.

What you plan to do in the outbuilding will dictate the power required. If all that is needed is a socket or two and some lighting, then the power requirements are fairly modest, a 13A supply would probably be more than adequate.

If all that is needed is a socket or two and some lighting, then the power requirements are fairly modest, a 13A supply would probably be more than adequate. To power a full workshop including equipment, lighting and heating however may require a far more substantial power supply.

A fundamental requirement for all electrical equipment selected for installation in your outbuilding is that it must be appropriate for the location and the expected use. This does not mean it has to be colour co-ordinated, but it does need to be moisture resistant if the building can not be assured of remaining completely dry.

When protecting power feeds to freezers or boilers in outbuildings, it may be appropriate to feed them from a dedicated circuit and treat them as fixed equipment. Thus the can be placed on the non RCD (or higher trip threshold) side of the outbuilding CU.

For more details including current ratings for the different cable types please see the main Cables article. Twin and Earth cable can sometimes be suitable for use outside, although generally it is better protected inside conduit or trunking. Note however that it is not robust enough for direct burial.