There are some tell-tale signs that your system is out of date and unsafe to work on (old-style rubber-sheathed cable, for example). But even if you live in a modern house with an electrical system that's been professionally checked and approved in the past ten years, things can still go wrong. So make sure it's safe before you begin work.

If you're in any doubt, get it checked by a qualified electrician.

Tackling an electrical or wiring job? You'll need the right tools to hand. We've a whole catalogue of specialist tools - from resistance testers and side cutters to wire strippers.