There are some foolish people that still use the method Joe cited.

I was once replacing a faulty dimmer in the bedroom in my old flat (with a filtered one that wouldn't wreak havoc with my AM radio reception) .

Whoever had installed the old dimmer didn't bother using the Marrettes that are INCLUDED in the package. They twisted the conductors together and taped up the splices with silver DUCT TAPE!!! [Linked Image]