Need help with bathroom light swith

[Squeeks2u2]

I need to replace my bathroom light switch but I'm not sure of the wiring. It is a one way switch with a light and exhaust fan. It has three cables from the wall which have three wires each: one black, one white and one copper colored. Which one is live? Is one of these a neutral or do I not have an earth wire? Which wire do I connect to the switch? I think I should have a short switched live wire going out from the switch and connected to all the black wires???? Help! A diagram would be appreciated. I'm replacing the switch because I think it's bad. Right now the light and fan are continuously on whether the switch is on or off. Thanks for any and all advice.

 

[JohnD]

This is a UK site and our methods and standards are different to yours, so please don't feel hurt if you don't get much response.

You may do better to find a US site.

 

[Squeeks2u2]

Any suggestions on US sites?