First let me preface this by saying that I am very comfortable doing basic electrical work. With this project my electrician is on vacation and won't be back for a few weeks but I wanted to see if I could tackle this myself. I have a drawing that I could attach but it is terrible so here goes.

  • 3 wire yellow romex to bathroom with red and black hot and white is neutral.

  • 3 wire yellow is going to a box with a GFCI and light switch.

  • Red is set to go to GFCI and to switch controlling two sconce lights.

  • Black is set to go through box and on to two can lights and the ceiling fan with switches on opposite side of the wall.

He told me where everything was going when he left but I am not one to guess when it comes to electrical and thought I'd ask. Here are my thoughts...

  1. black bypasses everything in the box and continues on to the fan and can lights.

  2. red goes to the LINE of the GFCI, then from load to switch next to it and on to the sconce lights.

  3. white pigtails to GFCI and on to can lights and fan.

I believe red is 20 amp and black is 15.

Does this sound right?

1 Answer 1


The yellow romex means that it contains 12 AWG wires which is suitable for any circuit 20 amps or less, this is appropriate.

The GFCI outlet seems to provide fault protection for the can lights that are operated by a switch.

Some things to check:

  1. The NEC requires that a bathroom fan is on its own circuit. You can verify this by making sure there is a 20 amp circuit breaker at the box that is feeding the red wire.

  2. The wire has different circuits on a shared neutral. This is acceptable only if the breakers for the two circuit are on a single throw switch. If one breaker trips then they must both trip.

  3. You didn't mention a bare equipment ground. Ensure that everything is appropriately grounded.

  4. Ensure that the manufacturer specifications on the fan call for a 20 amp circuit.

  5. Is there also a switch for the fan? You didn't mention it but unless you want it to run constantly then it will need a switch.

  6. You mention that you believe black is 15 amp and red is 20 amp. I can't believe the lights would require 20 amps and the fan 15. Double check which color leads to what circuit breaker before you continue.

  • 1
    Can you provide a code reference for #1?
    – Tester101
    Jul 29, 2013 at 11:24
  • Yeah. I don't see why a Bathroom fan needs to be on it's own circuit. It's neither high current nor mission critical. Jul 29, 2013 at 18:34
  • 1
    Thanks everyone and agree on the ceiling fan that it shouldn't matter. Now if it had a built in heater that would most likely be a whole different story.
    – mike mike
    Aug 1, 2013 at 4:27

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