I'm learning to wire and have done okay lately, but now I want to tackle adding a Ground Fault Breaker to my panel to power some outdoor receptacles and landscape lighting. I've already run 12/3 (in the grey sched 80 conduit) in an exposed ditch that was used to run power and gas to a new backup generator. It has been filled in. For now I am setting up two or three outdoor receptacles on the black run to our fence which will be used for a variety of events... social/xmas lighting/vacuum for vehicles/power tools/etc. The second hot (red) will be run to the front of the house in a couple of months to power two or three receptacles on our sizable wrap around front porch for the same type of events.

Problem I think I am running into is at the panel. I just realized that I am down to two open slots that are both side by side on the very bottom of the panel. From what I am reading I will want to use a 20amp GFCI breaker but I'm thinking I need a double pole breaker(?). If that is the case, am I out of luck if I only have two single side by side slots at the bottom of my panel? Are there 20amp breakers made that would accept 12/3 wiring AND fit into a single slot?

If "NO", can a 12/3 wiring setup be used across two separate single side by side 20amp breakers? I see the issue of sharing the common/neutral wire as being a major problem if I tried this approach.

I'm open to suggestions short of re-running two runs of 14/2. The hole (through our 20-inch concrete foundation) I will use to run the 12/3 only has just enough room left to get through. I fear pulling two 14/2 lines will be way too tight.

I do have the option of removing a breaker on one side of the panel because it's use is questionable. Once removed I would have to then move all the breakers below up a notch to make the bottom right have two open slots. Is that a lot of work to move them up? I've not done work in the panel before so don't know if doing this requires any rewiring or if it is just a matter of popping the breaker out and moving it one higher and popping it back in.

Again, I'm open to any suggestions and look forward to some constructive feedback!

*****UPDATE 4/20/2014*****

After looking closer at my wiring panel I see that the issue of limited breaker space may not be an issue after all. We recently had a natural gas backup generator installed. When installed, a transfer switch was also set up right next to the wire panel. In the process of rewiring, it appears the majority of breakers were redirected to the new transfer switch. It appears that I now have about 10 or 12 breakers available (they no longer have a hot wire going to them)... to include 2 unused 20amp double pole breakers. I'm thinking now I can simply replace one of the 20amp double pole breakers with a 20amp GFCI double pole breaker and be done with it. I did note the neutral bar still uses the original neutral wiring but see that there are at least 4 open neutral slots. I will consult with the electrical contractor who did our back up generator install.

Does this make sense that the transfer switch would be the primary source of control for the circuits on back up? Does it also make sense that the breakers in the original wiring panel are available for other uses?

*****UPDATE 4/21/2014*****

Just heard back from the electrical contractor re: availability of those breakers. All of the breakers that have no wires are now available for other uses. I can now replace one of the existing 20amp double pole breakers with a 20amp GFCI double pole breaker! Makes my day!

1 Answer 1


You will need a double pole breaker, or two breakers connected by handle ties for a multi-wire branch circuit. If you're wiring outdoor receptacles, you'll likely want GFCI breakers, instead of AFCI.

You should be able to shuffle breakers around in the panel, to accommodate the double pole breaker.

All that said. It sounds like you are quite inexperienced, and you may want to either do more research, or find somebody who has electrical experience to help you.

  • Wow... looking back at my comments I can see my rookie experience shines through LOUD. Appreciate the feedback. I did intend to suggest I would need a GFCI... but had just finished watching a video on installing an AFCI (didn't realize there was a difference). For what it is worth, I ALWAYS have an experienced electrician check my work and would certainly have one watching my back here. Appreciate the concern. Will edit original to see if it clarifies anything.
    – user21096
    Apr 20, 2014 at 15:37
  • AFCI breakers offer both arc-fault and ground-fault protection of equipment, but for outdoors in residential you'll need ground-fault protection for personnel.
    – Tester101
    Apr 20, 2014 at 16:56

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