In my bathroom near the sink is a GFCI outlet. I installed a new medicine cabinet and I want to add lights that currently do not exist. I will connect these fixtures with Romex wiring that I will install. But what I want to know is, can I pigtail my new lights from the power that currently connects the GFCI on the same wall? I just read that a GFCI has to be powered by a separate circuit on another forum. But I'm not sure if this is correct. If this is the case and I CANNOT pigtail from the GFCI can I run a Romex from an outlet from the bedroom next door and run it to the same junction box. To keep things looking neat and tidy I want to replace the existing GFCI with a two gang junction box that will allow me to have a GFCI and a light switch all under one switch plate.

If I can do any of the above would you be willing to provide me with detailed instructions?

Thank you.

By the way, this is the light switch I want to add in the long run:

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Photo of blue junction box below added 03/19/18 at 2:35PM PST

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Drawing of my junction box to explain what's what:

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Should I just follow this diagram? I need visuals and I can duplicate this since I can see it. But this doesn't look anything like what Jim Stewart was telling me to do in terms of wiring: enter image description here

This wiring diagram belongs to do-it-yourself-help.com. The original can be found here: https://www.do-it-yourself-help.com/gfci_wiring_diagrams.html

  • What else is on the circuit that feeds that bathroom GFCI? Mar 18, 2018 at 12:55
  • 1
    Turn off the one breaker that powers that bathroom receptacle. All other breakers must be on. Did any receptacles in other bathrooms also lose power? This question is the key to the answer. Mar 18, 2018 at 18:52
  • No other bathroom GFCI's went out. I went through the house to check. But what I did discover was that the same circuit controls the lights and fan for the bathroom in addition to turning off the GFCI on the other side of the wall. So, was this all done incorrectly to begin with?
    – Adrien
    Mar 18, 2018 at 21:04
  • What room is that GFCI on the other side of the wall in? Mar 19, 2018 at 22:18
  • The GFCI is in the bathroom and there is a bedroom on the opposite side of the wall where the junction box is located.
    – Adrien
    Mar 19, 2018 at 22:27

2 Answers 2


The NEC reference is Article 210.11 (C)(3) - It basically states that you must provide one 20A circuit to supply bathroom(s) receptacles(s) with one exception. "Where the 20 amp circuit supplies only one bathroom, outlets for other equipment within the same bathroom shall be permitted to be supplied ...".

All that being said, if your dwelling was built prior to this becomming code, you will fall under the grandfather clause which is pretty much explained by @Jim Stewart.

So if you want to upgrade you can or you can leave as is.

Hope this helps.

  • 1
    So modern NEC does allow a single 20-A circuit to power all the "outlets" (at least one receptacle (or more?), all the lights, and exhaust fan, if any), in one bathroom, right? The current poster just wants to add lights on the same 20-A circuit as the receptacle and so his upgrade will fully conform to the NEC, right? Mar 19, 2018 at 18:58
  • 1
    @JimStewart - From a code stand point, yeses, but only if that circuit is only serving one bathroom. Mar 20, 2018 at 8:51

Electrically there is no problem with powering the light with the hot and neutral feed to the GFCI receptacle. You could use pigtails to the receptacle line (and not use the load connection) and to the light switch so the lights would't go out if the GFCI receptacle tripped. Or you could use the load connections on the GFCI receptacle if for some reason you want GFCI protection at the lights. The lights would then go out if the GFCI receptacle is tripped. If the circuit is 20-A with 12 AWG copper or 10 AWG aluminum, be sure to use this same size wire for the light cable.

But I think modern code may require the receptacle to be on a separate circuit from the bathroom lights, although for the life of me I cannot see why. Our 1971 tract 2-bathroom house which we have occupied for 40 years has ONE 15-A circuit (12 AWG AL) for both bathrooms--lights, exhaust fan, heat lamp and a receptacle in each. This does not meet modern code, but I think is grandfathered in. It works for us, but wouldn't for everyone. The breaker has never tripped, but probably would if we had two hair dryers going at the same time.

Years ago I installed a 15-A GFCI receptacle in the upstream bathroom, and this worked fine to protect both bathrooms. Later (for some reason) I took out the GFCI receptacle and put in a 15-A GFCI breaker. This works fine for us.

  • Thanks for responding. So when you say not to use the load connection are you saying that I would attach the lights directly to the Romex that is running from the circuit? And then I can pigtail from the lights to the GFCI? There is Romex in there now and I'm pretty sure it's 12g.
    – Adrien
    Mar 18, 2018 at 21:05
  • To have the lights stay on if the GFCI receptacle trips, connect two pigtails (6" long pieces of #12) to the line hot (so three wires in one wire nut). For the hot black one pigtail goes to the line hot on the GFCI receptacle and the other goes to the switch. (The black of the cable to the light is attached to the other side of the switch.) For the neutral white, one pigtail goes to the line neutral on the receptacle and the other to the neutral in the cable to the light. Same for the ground. Mar 19, 2018 at 2:49
  • @ Jim Stewart. I understand now. Thanks. For the time being I am going to use a standard switch with the brass and silver colored connections. I will follow your instructions but when I get my push button switch with dimmer it will come with 4" hot/neutral and ground wires. Can I use those to replace one of the pigtails when I install it later? It is not copper inside the rubber coating, but more like thin silver colored strands that are braided or twisted together. By the way, I provided an image of the push button switch in my original post. See above.
    – Adrien
    Mar 19, 2018 at 19:59
  • @ Jim or anyone who is willing to help. I tried to rewire the junction box and it is not working out. The circuit at the breaker box keeps flipping back to off when I try to turn the power back on. So I know I did something very wrong. I tried making two pigtails to connect the Romex power source to both the outlet and the switch. But something doesn't seem. Can you guys look at my drawing and photo that took today of my new blue junction box? In my drawing the "O" stands for outlet and the "S" stands for switch. That's the order I want things to be in.
    – Adrien
    Mar 19, 2018 at 21:32
  • @JimStewart, I think the logic is that if lights and outlets are on the same breaker, tripping the breaker by some load on an outlet would leave the room with no light, which could be a safety issue. It looks like they make an exception for wiring a single bathroom.
    – fixer1234
    Mar 19, 2018 at 22:51

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