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dldubose 07-21-2012 10:15 AM

Changing bathroom light/fan/heater switch
I need to change the bathroom light/fan/heater switch. The old switch has three screws on the left with a black wire attached to each screw. On the right side there are three screws with a black wire attached to the top and bottom screws and a white wire attached to the middle screw. There is a ground wire attached to the switch unit. The new switch has three screws on the left side, a ground screw on the switch unit and only one screw on the right side of the switch. Where do I attach the one white wire and the other black wire?

freedomlives 08-06-2012 04:28 PM

Do all 5 black wires go out of the junction box?

Does one circuit breaker control the fan/heater/light unit? If so:

What you'll need to do, with the electricity on, is check each wire with a multimeter and see which ones have 120V with respect to ground. In other words, hold one probe of the multimeter against the ground wire, then check the other 6 wires. I'll bet that 3 of them will be 'hot'. If the fan-unit was wired correctly, you'll need only one of these hots, and the three wires reading 0 volts will each be going to the fan, heater, and light respectively.

Now, with the power off:

Those three wires reading 0 volts should get wired to the three screws on one side, and one of the wires reading 120 volts should be wired to the single screw on the other side, as well as wiring the ground appropriately.

It seems odd to me though, if it is all one circuit breaker, that the installer would pull down two extra, unneeded wires.

freedomlives 08-06-2012 04:30 PM

I should add:

It may not be how I am guessing. For instance, if after doing this only one part of the unit works, then the unit in the beginning may have been wired wrong, having hot feeding into the unit and out through the switch to neutral. In which case it would be necessary to pull the unit out of the ceiling and inspect how it is wired up.

gregzoll 08-06-2012 04:31 PM

Didn't it come with an instruction sheet?

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