I bought a single pole dimmer switch to install in my dining room and when I took the old switch out nothing looked right. There are two wires which were joined together by another single wire which was attached to the top screw. There was another single wire (I believe the ground wire) attached to the bottom screw. I disconnected the first two wires and attached them separately to the black wires on the dimmer and attached the ground wires together. It didn't work. I've tired several different times with no luck. I put the wires back the way they were and attached them to the old switch and they no longer work ether. Help! How can I fix this problem? The old wires appear to be a very thick copper covered in black plastic and cloth.....
The 'answerer' Justin K thinks you have knob and tube wiring. A lot of early electrical installations were done in the old days with out a ground, many types of early 'romex' did not include a ground. You may or may not have 'knob and tube' wiring - but it really dose not matter. The two wires which were joined together and had a third wire attached are the hot wires. The other wire (lower screw terminal) is the 'load' wire - it goes out to your light fixture. The reason the those 2 wires were attached together is that one of them is hot, and the other wire is a 'feed' to supply power to your next switch or receptacle. I am an electrical contractor, this is how I would fix the problem - I'm not suggesting that you do it though. #1 turn the breaker/fuse back on. #2 use a voltage tester to determine which wire is now hot. #3 touch the hot wire to the other wires 1 at a time. The hot wire when it is touching the 'load' wire will turn on the lighting fixture. Mark the 'load' wire with some black electrical tape. #4 turn the power back off #5 attach the marked 'load' wire to one of the switch terminals. #6 take the other 2 wires (incoming power, and the out going power) and join them together with a third wire ---LIKE IT WAS ORIGINALLY. Place that third onto the other terminal of the switch. it dose not mater which terminals you use - it will work just fine.
The green wire is ground. In a house that old, probably the best thing you can do with it is to connect it right to the steel box. Look for a screw you can loosen and wrap the green wire under it. Retighten. If there are only two other wires from the switch, you should connect one to the black wire and one to the white wire. I don't know why your first dimmer fried. This is a perfectly normal hookup. It should even be illustrated on the packaging for the dimmer, or in the instructions.
