I am remodeling my 2nd floor bathroom and adding laundry (gas dryer). I replacing old circuits with 2 new circuits. One dedicated to washer/dryer and another for one outlet, 2 vanity lights, 1 general illumination light, and for the exhaust fan/shower light. Can I make one 12/3 run from my basement and use a common neutral for the 2 circuits or do I have to run two 12/2 cables?

Also, how do you make the fan GFI protected since, in my floor plan, it makes no sense to power it through the outlet box which will have a GFI outlet?

Thanks
DS


OK sorry. Nevermind. I found an old thread on this very topic that made it clear that the shared neutral is not a good idea. I am planning to run a single 12/4 cable and splitting off the 2 separate circuit at the bathroom.

tkrussell

Shared neutrals are allowed, but in the event the neutral breaks due to a loose connection, the two 120 volt circuits can have 240 volts applied across them and burn out the items connected to those circuits.

Separate neutrals for each circuit is best.

Why not utilize the GFI outlet to protect the fan/light? If you chose not to, you can use a blank, or deadfront GFI device ahead of the fanlight. This can be located anywhere, but must be accessible and mounted in an outlet box. looks like a GFI outlet with out the plug openings.

I would use the GFI outlet in the bathroom to feed the fan/light switch and then to the fan light.