A little knowledge is a dangerous thing.

[Chillum]

I'm putting in a new light fitting. I have five wires coming down from the ceiling. two are red, two are black, one is green. I put the two red wires into the "live" bit, i put the two black wires into the "neutral" bit, I attached the green wire to the "earth" bit. I put the fuse back in, and it blew. Have I done something stupid?

[Hippy]

Very definitely! Two red/black  pairs. One pair is the mains feed and the other is from the switch. You need to put the switch in series with the red feed, so first determine which pair is which. A neon screwdriver will help you to find the live, but only have the juice on for the purpose of finding this and ensure all wires are standing proud and not in danger of touching anything else or other wires. REMOVE THE FUSE AT ALL OTHER TIMES. The screwdriver test will not help you find the feed neutral. You will need a resistance or continuity tester to deduce that by elimination.

Having located the live and switched the current off, label the live and discount it for the next test. turn the wall switch on and then test the remaining red against the two blacks. You should find the switch pair that way. Label these and the remaining black will be the feed neutral.

You now have feed live (1), feed neutral (2), Switch red (3), and switch black (4). Connect as follows: (1) and (3) together on an isolated terminal; (2) to one bulb connection and (4) to the other bulb connection. Finally all green earth wires to the earthing terminal.

Now, if any of this is mysterious or confusing to you, obtain qualified help. Do not mess with electricity. Not only can it give you anything from a nasty shock up to death, but you can set fire to your house  by blowing up the wiring - very expensive. An electrician is a lot less money and loads more peace of mind.

[jake-the-peg]

No Clarion Street.

The new Part P building regs highlight certain areas Kitchen, Bathroom, Outside the house (basically anywhere where you might come into contact with water). To do electrical work here you need to be Part P certified or if you'r not you can have your work certified by building regs (��+delay).

Frankly the existing situation where anybody could go to B&Q and buy a power shower and wire it in themselves really was rather dodgy and in need of changing

[Chillum]

Thanks all. Too much for me. I'll ask a man who knows.