Bathroom electrical


Old 05-21-15, 10:57 AM
Thread Starter
Join Date: May 2006
Location: Portland OR
Posts: 11
Bathroom electrical

I'm completely remodeling a bathroom. New electrical to replace old knob and tube. There will be:

2 switched lights - one ceiling and one vanity
2 receptacles - one at the vanity and one on an opposite wall
Ceiling fan - located above the tub/shower
Radiant heat floor mat

Given the fan must be wired to a GFI breaker and is rated for 0.18 amps, can I wire the receptacles and fan to the same 20A breaker?

Can I wire the lights and radiant floor mat (depending on size, about 4 amps) together on another 20A breaker?
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Old 05-21-15, 11:16 AM
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Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,502
The floor mat will also need GFCI protection. I would do the receptacles on a 20A GFCI circuit; and the other stuff on another 15A or 20A circuit. The other circuit could also power lights outside the bathroom if necessary. GFCI receptacles or blank faces can be used as a much cheaper alternative than GFCI breakers.
Old 05-21-15, 02:51 PM
Thread Starter
Join Date: May 2006
Location: Portland OR
Posts: 11
Thanks, but not sure I follow. You're saying put GF receptacles on their own 20A circuit and everything else on one circuit, then I still need GF breaker for the fan - so why not also connect regular receptacles to that breaker?
If the floor mat is GF protected at the thermostat, then regular 15A or 20A breaker for everything else, right?
Old 05-22-15, 02:32 PM
Join Date: Aug 2012
Posts: 7
You have two routes you can take for bathroom circuits.

A) You can use a single circuit to feed receptacles, exhaust fan, lights, and other loads in a single bathroom. This circuit may not serve other bathrooms or other locations.


B) You can use a single circuit to feed receptacles ONLY in more than one bathroom. Lights, exhaust fans, and other things in the bathrooms must be served by some other general purpose circuit (for example the circuit serving the bedroom lights, etc). The circuit feeding the lights etc need not be GFCI protected, subject to the following caveat:

Exhaust fan manufacturers typically require that exhaust fans be GFCI protected when directly over the tub/shower footprint. They do not need GFCI protection elsewhere in the bathroom, so most people choose to install the fan near, but not over, the tub/shower. Since steam rises and will follow the ceiling, it will be just as effective near the tub/shower as it will be directly over it.

As for design philosophy, you're right at the limit for a 20A circuit if you run the bathroom receptacles, lights, exhaust fan, and heating mat all on the same circuit (a blow dryer is usually 15A), so this would be an argument for putting the heat mat on some other circuit besides the one serving the bathroom receptacles (I'm assuming the mat has its own GFCI protection). Be aware that the heat mat, if placed on some other general purpose circuit in the house, must not draw more than 50% of the capacity of that circuit.

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