I have a GE PowerMark Gold Load Center breaker panel that is currently maxed out (no slots left), 38 of 40 poles used (4 of the slots are used by 60 amp double-pole circuit breaker, leaving 2 poles unused, but not slots left). Most of the other breakers are "slim" breakers (only take up 1/2 inch).

I am upgrading my pool pump from a 115V pump to a 230V pump, and need to upgrade the 20 amp single pole circuit breaker to a 20 amp double-pole breaker. This will require I use up at least another slot.

My current plan is to join two adjacent lighting-only circuits (all LED bulbs, no Shared Neutral Circuits) in order to free up a slot.

This will technically work fine, but I won't have GFCI protection on pool pump. The only GE listed 20 amp GFCI double-pole breaker takes up 4 slots (THQL2120GFTP), and I don't have additional circuits I can easily combine, and GE doesn't make or list tandem circuits.

So I'm a bit stuck on how to get this working.

My current idea is to install a small outdoor breaker panel inline with the pool pump (so on the new non-GFCI 240V 20 amp circuit -- with the existing 12 gauge wiring), and put the appropriate GFCI breaker there; so the "Mains Line" would be the original wire that goes to the pool pump.

(Nothing in my pool configuration is bonded, so this set up doesn't making my bonding situation any worse - I don't think.)

The part I think may be a problem here is that there is no connection between the main panel neutral bus and the new outdoor panel's neutral... so the GFCI won't work.

Am I correct that my outdoor-panel-using-existing-wiring GFCI idea won't work? What other DIY options might I have?


1 Answer 1


The usual setup is:

  • Large breaker (e.g., 50A) in main panel.

  • Hot/hot/neutral/ground cable (or wires in conduit) from breaker to subpanel, sized based on the breaker.

  • Subpanel near the pool (but at least several feet away). This panel includes multiple circuits:

    • Pump
    • Heater (if applicable)
    • Lights (e.g., outdoor lights)
    • Pool lights (e.g., in the pool, if applicable - typically low voltage for safety)
    • Convenience receptacle (for phone charging, pool cleaning equipment, etc.)

And then there are 3 possible ways to provide GFCI protection:

  • Breaker in the main panel. Not an option for you, based on the problem you have reported, but often works well because it is protected from the weather/pool water/etc.
  • Main (likely "backfed") breaker in the subpanel. This also functions as a shutoff for the panel. This can be any size >= the feed breaker.
  • Individual breakers.
  • Receptacle. Note that this does not work for 240V loads (like your new pump) as GFCI/receptacle is currently generally available (may yet change in the future due to increasing GFCI requirements) only for 120V receptacles.

The first two (feed breaker or subpanel main breaker) protect everything in the subpanel. The last two are piecemeal - i.e., each circuit in the subpanel needs to be protected one way or the other.

You have a big problem with your panel. It sounds like it is really a "20 space/40 circuit" panel, and you have almost everything using 1/2-size breakers. There are some breakers that require 4 spaces (traditional spaces), but that is very rare these days. What you describe as 4 spaces is really 2 spaces by the traditional way of counting them.

You have a few options:

  • Combine enough circuits to end up with two full spaces and put in the 240V double-breaker/GFCI. That is probably going to be easiest. But beware: Certain circuits can not be combined - e.g., you are required (and grandfathered is OK, but you can't make things worse) to have 2 kitchen countertop receptacle circuits, 1 laundry circuit (not counting the dryer), 1 circuit for each bathroom (can be for all bathrooms if done right), etc. This will only solve your immediate problem.
  • Add a subpanel next to your existing main panel. If it is the same brand/type (not the exact same model, but using the same breaker types) then you can transfer a few circuits now and make more changes later. One possibility is to put in a much larger panel, make it a subpanel for now and eventually make it the main panel. This will solve some of your larger problems.
  • Combine enough circuits to end up with two full spaces and put in a larger 240V double-breaker/GFCI. Then run new cable or conduit/wires to the pool and install a subpanel. This will solve some of your larger problems. Note that doing this will bring up a bunch of additional issues. Essentially, you will have to bring the pool area up to current code with respect to things like: convenience receptacle, lighting, GFCI protection for everything else (i.e., besides the pump which you are already dealing with). But water and electricity can be a dangerous combination, so it is worth considering. One big catch: space. You need 30" x 36" open space in front of a subpanel. You also need to have the subpanel at least a certain distance away from the pool. Depending on where the pool is in relation to your house, that could get a bit tricky.
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    As far as I know, none of the major breaker manufacturers have made GFCI or AFCI breakers in "half size" yet. But, as I explained, for GFCI there are plenty of options. Interestingly, AFCI does not have as many options, but AFCI is more fire safety than life safety and so it is not required in as many places (yet...) Aug 21, 2023 at 0:52
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    Siemens has a tandem afci now. Aug 21, 2023 at 0:59
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    The catch is these things change very slowly. And there is more incentive to make the AFCI smaller than the GFCI (though I am sure they will get there eventually) because AFCI has to, practically speaking, be at or near the panel, while GFCI can be at the panel, at point of use, or anywhere in between. Aug 21, 2023 at 1:01
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    I know square d makes 1-slot 2-pole gfcis. If I could use a 1 slot GFCI here it'd make things much easier! Aug 21, 2023 at 1:09
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    Just pigtailed 3 pairs of breakers to free up 3 slots. I'll run some more-than-typical loads over the new combined circuits over the next few days before pulling the trigger on the pool pump GFCI switch over. Thanks for the insights! Aug 22, 2023 at 20:54

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