I live in a rented flat filled with dimmer switches. One day we knocked a rack of halogen lights connected to a dimmer and blew a fuse. I reset the fuse but the circuit with the rack of halogen lights never worked again... We tried changing the bulbs, but it appeared that the dimmer switch itself has blown.
When I opened it up, however, I found this:
I can't quite fathom how two live wires can go into the same dimmer. What's going on here? Could it just be a wrong coloured wire?