1 way light switch cable colours?

[mabos22]

hi
I have read your answers on how to wire a 1 way light switch but you don't mention what colour cables go to wich terminal.i.e what colour is common and what colour is L1?.
I know i could check another light switch in my house but i am replacing all of my light switches and every time i open one up it is different to the last. What is the correct wiring ?
Cheers

 

[loftus75]

If your house was wired in the last 25 years or so, and the switches you're replacing are 1 gang, that is there is only one switch, you will only have 3 wires at most going to your switch and one of these wires will be an earth, the other 2, a red and a black are the switch wires. In reality these are the live wires, even though one is black.

What happens is the wires going to the ceiling rose have been arranged so that the live wire jumps from one ceiling rose to the next, the wire to the switch is taken from the ceiling rose down to the switch and then back up to one side of the light bulb. So when you switch the light on, the live wire from the ceiling rose passes electricity to the switch and is then directed back to the light bulb.

This being the case, you can put the wires to common and either L1 or L2, the light will still work, though if you place one side to L2 the switch will rock the wrong way, but it will still work.

However if your house is wired another way, it may be a good idea to have an electrician look at it as it is likely you'll need to consider rewiring....if so I'm sorry to have brought you bad news

 

[mabos22]

Thanks for the reply
Luckily its not the later.
Cheers.