I bought a bathroom fan timer and tried to install it. It has four wires and the wall switch circuit has only 3 wires. What do I do?
sounds like you have one wire short in the box. you need to power the timer. which means you have to use your ground wire for the neutral wire. and this means you have no proper ground. so wire it like this old black to black old white to red old green to new white and to box new green to box. to do it properly you need a 4 wire cable coming into the box and going to the power source or to where there is a proper neutral wire. the thing is the timer wants full power going to it complete with a ground circuit. the switch before it was just that a switch which interrupted the power on one side of the fan so all it needed was 2 wires and the ground to be properly wired
What are the colors of the old wires and what colors are connected where? New switch black to old switch black. New switch red to old switch white. New switch white to through going whites, (should be two twist locked together). New switch green to screw on existing metal box or leave disconnected.
Yes, but don't listen to these other answers (scary,lol). The bare copper wire is always the ground wire and it is usually a green wire on the switch (timer), so connect those together. There will be 2 wires in the electrical box (probably both black, but one might be white depending on how it was wired), either way they are both black wires and if you touched them together the fan would turn on. One of them will be a constant power from the panel and the other will go to the fan. Now, you will have to look at the instructions that came with the switch, to see which of the 3 wires goes to the fan and which 2 wires get hooked to constant power. You will have to determine which of the 2 wires in the box is constant power and if you have a tester it's easy, if not you have to touch the wire (I'm kidding). Electrical is quite simple, you just have to do it systematically one wire at a time. I hope I didn't confuse you, but the reason I explained all of this is it's the only way because of different circumstances. Also, if you don't have a tester and there is one black wire and one white wire in the box (not counting the white wires connected together with a marette) then the black wire is the constant power and the white goes to the fan.
