I have a single light fixture in my bathroom on onw switch. The room has no fan and no outlets. I want to add one fan, and add one gfci outlet.

I have two ideas. Looking for pro / con / feasibility + wiring diagrams.

Simple Solution

Combine fan and light on single switch. Replace single switch with switch / outlet combo like below.

Single Switch / Outlet Combo

I assume I can run power from the light to the fan. And then rewire the switch. Is it that simple?

Right Solution

Replace the single switch with 2 switches: 1 each for light and fan. Then have a gfci outlet placed by the vanity. PROS: 1. I can leave the fan off when not showering. 2. The outlet is by the vanity, and not on an awkward wall with a switch.

New Switches

Sample Outlet location


I found this with the preferred answer being close. Wrong switch type, and it assumes power is run to the outlet then to the light. My existing source is to the switch. I figure the only way to have the outlet after the switch, is to have it be activated by the light (not fan) switch. That's less than ideal, but I'm open to it, since I'd never need the outlet to work with the light off.

Also, old house, so there are likely no grounds.

New Info!

Bathroom Circuit Diagram I went into the attic and traced all the wiring to / from the bathroom light. There's more! I drew a basic diagram. I'm sorry it's not an official drawing, but hopefully clear enough. Also, it's on a 15 amp fuse. And this is all new wiring, and surprisingly, includes grounds.

New Plan I'm thinking I scratch the outlet idea. I'll only add a fan. I'll add a switch next to the light switch, and tie the fan power into the light. Thoughts?

Happy Ending Installed just the fan, no outlet. I added a second switch using an old work box, right next to the existing switch. I wired it to the light as expected, and it's worked perfectly. Thanks guys!

  • What are your walls made of and are there studs between the switch and the vanity? The complexity of running cable depends on how much wall patching you want to do and if you need to drill through studs. – Hari Ganti Feb 28 '18 at 19:24
  • I believe the switch is on sheetrock, and the outlet will be on a lath and plaster wall. All the wiring is run through the attic, so I'll pobably do the same. There are in fact studs, and a door between the switch and vanity. – Dylan Cross Feb 28 '18 at 19:32
  • Big question: is there anything else on this circuit besides this bathroom, and is it a 15A or a 20A circuit? – ThreePhaseEel Feb 28 '18 at 23:24
  • Answers: The circuit has a 15 amp fuse (I'm assuming 14 gauge wire, but not sure). There is MORE on the circuit. Details to follow. – Dylan Cross Mar 2 '18 at 2:19

If we are talking recent code, NEC requires a 20A circuit dedicated to bathroom receptacles. This circuit cannot service lighting in other rooms but there is an exception for what you contemplate: to service a 10A or less load for fan and lights in the one bathroom. The point of this requirement is so that your blow dryer doesn't pop the circuit.

When you modify this circuit you need to bring it up to code and that may prove difficult if the branch servicing that light switch is only 15A and/or services other light switches (as I suspect it does). Getting this up to code would then require you to run a new 20A branch circuit from the service panel.

Having said that, either of your proposed configurations works fine. There is no problem pigtailing off the line in the switch box to install an unswitched outlet box elsewhere. Just do this on the line side of the switch.

[210.11(C)(3)] One 20A, 120V branch circuit must be provided for the receptacle outlets required by 210.52(D) for all dwelling unit bathrooms. This 20A bathroom receptacle circuit must not serve any other outlet, such as bathroom lighting outlets or receptacle outlets in other rooms (Fig. 1). A 15A, 125V receptacle is rated for 20A feed-through, so it can be used for this purpose [210.21(B)(3)].

[210.11(C)(3), Exception] A single 20A, 120V branch circuit is permitted to supply all of the outlets (including outlets for lighting and equipment) in a single bathroom, as long as no single load fastened in place is rated more than 10A [210.23(A)] (Fig. 2).


You'll need to run a new homerun to put a receptacle in

You'll need to take some 12/2 and pull it back to the panel, punching it down to a new 20A breaker in it, to put a receptacle in that bathroom.

However, the fan's fine

The exhaust fan, though, can be put on the lighting circuit. It's probably best if you put in a larger box instead of using a double switch though, to keep any potential for box fill trouble to a minimum.

  • I now figured the outlet would be a second project b/c it requires running a new line. I will do a double box , and add a second switch. – Dylan Cross Mar 2 '18 at 14:14

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