Martin, the bathroom receptacle(s) is required to have one dedicated 20 amp
circuit (#12 wire) feeding it as per the current National Electrical Code.
It won't pass inspection with a 15 amp feed.

You cannot use a three wire to feed two separate circuits and have one
protected by a GFCI circuit breaker. Because of the design of the GFCI and
how it operates it will trip each time there is current on both legs
concurrently. It just doesn't work with a shared neutral. You need to use a
two wire cable for the GFCI breaker protected circuit. You might get it to
work by using a GFCI device at the load end connecting one hot and the
neutral of the three conductor cable, but I suggest that you change to a two
wire to keep nuisance tripping to a minimum.

You should check the manufacturer's requirements for the floor heating and
save the instructions for the electrical inspector for verification.


John Grabowski
http://www.mrelectrician.tv



"martin" wrote in message
...
current setup

Bathroom distribution:

2 breakers : 1-15A GFI, 1-15A, 1 pole duplex .
2 wires from breakers, 1-2wire, 1-3wire

2 wire cable
- connected to A of 15A duplex breaker
- running to GFI receptacle

3 wire cable
- 1 hot connected to B of 15A duplex breaker
- runnig to lights, fan
- 1 hot connected to GFI breaker
- running to floor heating cables

- neutral connected to GFI breaker

is this setup OK? Does the GFI breaker neutal works ok if shared between
2
breakers?
Originally this setup was planned beacuse the receptacle is on the other
side of bathroom.
3 wire cable runs to wall with switches for lights, afan, and floor
heating
thermostat. Will the circuit work, or is there a chance of GFI breaker
tripping?
If needed, I can rerun the cables, but beforte I get into it, I want to be
sure that it is required.

Thanks.

martin