Bath Fan Wiring

[depawl]

Hello all.
When wiring a bath exhaust fan with light, and wanting to have the fan and light on separate switches, can one run a common neutral wire (e.g. 12/3)? This is an LED light that will be on a dimmer, and it's a GFCI circuit.
Thanks.

 

[ImOld]

Normally you cannot share a neutral from a GFCI receptacle. Some GFCI breakers you can and they state this.

Be careful with the LED and dimmer. The must be compatible and some LED luminaires will require a 3rd control wire.

Or... if it's all in an easy access area, throw it together and see if works. Shouldn't be any 'magic smoke'.

 

[Sponsor]

 

[Stuff]

As long as it is the same circuit you should be fine as it is done all the time this way.

Both hot and neutral need to come from the "line" side of the gfci receptacle.

 

[depawl]

Thanks.
How would one determine if
"Both hot and neutral come from the "line" side of the gfci receptacle"?

 

[Stuff]

Assume you have a single circuit.
If you have a GFCI breaker then everything is on the load side and things work fine.
With a GFCI receptacle the line side (hot and neutral) comes from the electrical panel. The bottom screws on the receptacle are marked "load" - usually with tape over them when new. Either trace wires or push the test button to trip. If your wires are still hot then they are on the line side, if they turned off then they are on the load side. Assume this worked before so both hot and neutral are both going to one side or the other.


Using the line side means that if the GFCI receptacle trips you don't lose your lighting. However if the fan/light is over the tub or shower it needs the GFCI protection so would be on the "load" side.

 

[depawl]

This circuit is on a GFCI breaker, so according to what you said everything is on the load side and should be OK, correct?

 

[Stuff]

Yes, with GFCI breaker all of the wiring is on the load side so should be fine. Only issues people have is if they tie in a neutral from another circuit which happened in old houses.