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Question:

help with bathroom fan wiring?

I attempted to change a bathroom fan to a new one with the help of a friend. He disconnected all the wiring without paying attention to what he was doing and what was wired where. We have a set of wires coming from somewhere (I presume the fuse box) to the fan that is hot regardless of the switch being on or off. That has a black, white and naked wire in it. Then we have another wire that comes from the switch that has black, white and naked as well. The fan has black, white and green. Can someone please tell me how to connect these as we have tried everything and the only thing that works is wired to the constant hot which of course won't allow us to turn the fan off with the switch...

Answer:

You need to pull your wall switch to see how it is wired. I suspect the original wiring used the black and white on the switch itself which would make the white actually black or hot instead of neutral. If on one side of the wall switch the black wire is wired and the other the white then you need to wire the black from the fuse panel to the black going to the switch. Then the white coming from the switch to the black on the fan. The white on the fuse panel wire would be wired to the white from the fan and all grounds(bare and green) wire together.
1) Turn off the power. 2) Install the fan completely into desired location. 3) Insert both wires into fan's junction box. 4) Twist the two bare wires together, install crimp sleeve onto them at the twist. 5) Find the green screw and connect ONE of these bare wires under it and tighten it down. 6) Cut the OTHER excess wire and fold all this connection up into the junction box. 7) Take the white wire that is coming from the (I presume the fuse box) , and connect it to the white wire that goes to the fan itself. Strip 1/2 of insulation and twist the wires together, install a wire-nut and fold this into the fan's junction box. 8) Take the black wire that comes from the switch and connect it to the black wire that goes to the fan itself. Strip 1/2 of insulation, twist the wires together, install a wire-nut and fold this into the fan's junction box. 9) All that's left is the black wire that is coming from the (I presume the fuse box) , and the white wire that comes from the switch. Strip 1/2 of insulation, twist the wires together, install a wire-nut. 10) Take a black Sharpie pen and color this connection's white wire black and fold this into the fan's junction box. This is known as a switch-leg. 11) Restore power and test. I will you with these two thoughts: 1) It is always best to hire a pro for this type of work. 2) Good luck and may God bless.
Follow Eaglewatcher's instructions and not only will it work, but you will be in compliance with the National Electric Code. When ever a switch is fed with a black and white cable the white Must Be used as the Hot. And it Must Be Permanently Identified as such. Most of us use a sharpie or black tape to do this. NEC Article 200.7(C)(2) Good luck.

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