how can i tell which is the live wire, ive got a light switch with 2 red wires and 1 earth wire trying to fit a dimmer help a s a p john

john naylor, November 2007

If fitting a dimmer switch it does'nt matter which way round the wires are connected, with the power to the lights OFF, fit one in the terminal marked Com and the other in the terminal marked L1. Even with a normal rocker switch it does'nt matter as the whole switch can be turned upside down, if need be, and screwed back to the back box. Zinggys advice about rubber gloves and working live should be ignored. Bet he's got spiky hair as well.

good luck

baz

baz, November 2007

hi j, only one of the red wires is live the other red wire is the return to the light unit. with the old switch fitted and the light off put a test screw driver to LI or L2 or COM terminal on the back of the switch the red wire that illuminates the tester is your live feed the other is the load feed and should not illuminate until you switch on. try not to electricute yourself at the same time. "TIP" get a good pair off rubber gloves...as you need to do this with the power on

zinggy, November 2007