In the past it was possible for those with DIY skills to install their own sockets and electrical systems but, since 1 January 2005, Building Regulations Part P requires that, in England and Wales, only qualified electricians carry out new electrical installation work, or that work is certified by a professional when completed (special waterproof fittings must be used, even in greenhouses and sheds, as the inside of these structures can get damp). However, it is legal for those who are competent to identically replace damaged sockets, switches and light fittings, or the cable for a single circuit if it is damaged.
Although you cannot wire in electical installations yourself, special kits that just plug into an indoor socket can be used. Plugged into an indoor socket, such kits contain a length of armoured cable (which is less likely to be damaged if accidentally struck with digging tools) with a waterproof socket and switch, already attached, at the other end. This can be attached to a convenient place outdoors. Ideally, bury cables 60cm (2ft) beneath the ground and place warning tape 15cm (6in) above any buried cables.