Bathroom GFCI wiring
July 3, 2010 9:59 AM   Subscribe

Our bathroom has a GFCI combo switch/socket where the switch is hooked up to the bathroom fan/light. It's wired downstream of another switch controlling the vanity fixture, and set up so that the socket is only hot when the switch is on. This makes it suboptimal for, say, charging an electric razor or toothbrush overnight, because that means leaving the fan on. What's the best way to change this?

From what I can tell, rewiring the socket so that it's not controlled by the switch means giving up the GFCI protection. If that's the case, is it smarter to hook up the fan to a standard switch, and add a new box upstream with a GFCI two-outlet socket? For extra credit, is there a better way still -- yes, YANMElectrician -- to consolidate the three electrical elements (bathroom light, bathroom fan, outlets) so that they all work independently and safely?
posted by holgate to Home & Garden (7 answers total)
Can you clarify your wiring situation? The only way I can parse your description is that you have a switch controlling your vanity fixture, which also controls your combo switch/outlet, which in turn controls your bathroom fan/light and is wired such that the outlet is controlled by the combo switch (i.e. in order for there to be power at the outlet, both your vanity fixture and your light/fan need to be on. However, that seems like a weird setup and doesn't really gybe with your second paragraph.

Can new wire be fished between these two boxes? Are you willing to open up the wall to add wiring?
posted by ssg at 10:58 AM on July 3, 2010

You could replace the breaker that feeds the bathroom circuit with a GFCI breaker. These breakers are quite expensive, depending on your panel a single pole 15A could be upwards of $100, a two pole (needed if you have a three wire circuit) can be a couple hundred dollars. This would give your entire bathroom circuit GFCI protection independent of the socket.

You'd have to run new switch wire to get everything to function independently. Shouldn't take more than a few hours but you'd need to repair your walls afterwards unless you get lucky and everything can be fished without cutting holes.

You could also add a second outlet to your bathroom tapped off a different circuit. For example if the rooms your bathroom shares a wall with have an outlet on the walls they share it is a fairly simple matter to tap into that outlet box from the bathroom side of the wall. I've done this once where the tapped outlet was behind the toilet (which is an awkward place for the new bathroom outlet) so in addition to the above toilet outlet we added another outlet two stud bays over which put the second outlet over the counter. When you are adding these boxes you only need to cut a box size hole in your wall. A special reno or old work box can then slide in to provide housing for your outlet and cover the hole in the wall.
posted by Mitheral at 11:13 AM on July 3, 2010

Sure. The vanity switch is physically located directly above the combo: the power wiring runs into and out of its box, along with the wiring for the vanity fixture. The power runs down to the combo box through a single short length of NM-B cable. The two switches work independently, so you can have the vanity off but the fan on and vice versa. The wiring for the fan comes out of the combo box and back up towards the attic.

Access to the boxes isn't a problem (they're near a recess cut for a medicine cabinet) nor is opening up the wall further.
posted by holgate at 11:24 AM on July 3, 2010

I think I understand what you have and what you want, but no promises. OK, so why not put a normal dual outlet with GFCI in the bottom box, and run a wire from that to a dual switch in the top box for the fan and the light?

This gives you two GFCI protected outlets along with a switch for both your fan and light that don't turn anything else off.
posted by Kid Charlemagne at 12:16 PM on July 3, 2010

If you have easy access, then you can do as Kid Charlemagne suggests. You'll need to move the fan cable to the upper box and add another short cable between the two boxes if you want both the vanity and the fan to be GFCI protected (as I understand it, your fan is currently GFCI protected, while your vanity is not).
posted by ssg at 2:01 PM on July 3, 2010

That's right, ssg. Would it make sense to re-route the hot wiring into the lower box and a GFCI dual-outlet, then connect the vanity and fan downstream from it on the load side? Or perhaps add a new box for the outlet, move the light switch to the lower box and use the upper box to extend the live wiring with wirenuts and tape?

Scanning through other online discussions suggests that the light and fan switches don't need to be GFCI-protected -- the fan isn't directly above the shower, which is apparently the determinator for code and safety. Is it worth it?
posted by holgate at 6:35 PM on July 3, 2010

Would it make sense to re-route the hot wiring into the lower box and a GFCI dual-outlet, then connect the vanity and fan downstream from it on the load side?

Yes, that would be it. Of course, it would be easier to put the outlet in the upper box, but that doesn't make any sense because you'll have cords dangling over the switch.

If you decide that your fan doesn't need to be GFCI protected, then your task is much easier: just re-wire the connections to the combo unit. You want diagram A in the instructions.
posted by ssg at 3:11 AM on July 4, 2010

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