I am in the process of adding a pool heater. 240V (60A breaker/40A max load/3 wire)

I also want to put this in a GFI. I have a SquareD/homeline box, which does not offer 60A GFCI breakers. So, I purchased a spa disconnect to place outside (in addition to the standard 60A breaker in the panel)

However, the run out there is pretty long - about 215'. So, I don't want to pull an extra neutral wire just for the hell of it. (I'm running 4ga wire to the heater due to the length of the run). From what I understand, 6GA wire would have been sufficient for the 40A max load and that length)

The GFCI that I got looks like it requires a connection to neutral. So, I can do things one of two ways.

  1. Spa disconnect in basement at panel, and wire up the heater direct. I'd rather not do this - I'd rather have the disconnect outside if possible. However, I know that I can fall back on this. This would (at least) shorten the length of the wire needed between the panel and the GFCI.

  2. Spa disconnect outside. I do have some spare neutrals out there already (for accessory power, pump power, and chicken coop power... 2x20A AFCI/GFCI breakers running over 8ga wire..

Question A Can I tie the neutral on the spa panel GFI to the neutral on one of the 20A return legs? Would this cause issue with the GFCI/AFCI function of on the main panel? I assume that the neutral wire is ONLY used as a reference - so I shouldn't be adding any real current to the return

Question B Can I tie the neutral on the spa panel GFI to the return ground? Technically, both are tied to the same bus bar in the main panel. (my question remains the same with the neutral in the GFI outside being more of a reference, and not really responsible for any "real" current needs)

  • I'm leaning to just install the disconnect outside, and try QA out. If it fails, then I replace the GFCI breaker with a standard breaker. The 2 outlets that are on a dedicated 20A circuit are both GFCI outlets.
    – Akshue
    Mar 16, 2021 at 18:49
  • 1
    Depending on where you live, I think the Spa Disconnect box needs to be within a certain distance (and line-of-sight) of the spa itself. You also need a 120V outlet within 20 feet.
    – Ron Beyer
    Mar 16, 2021 at 18:51
  • Well, it's technically not a spa. It is a pool heater, I'm just using it as a GFCI instead of running breaker-only. The pump and accessory outlets are (2) 20A/120V circuits, with GFCI/AFCI combo breakers.
    – Akshue
    Mar 16, 2021 at 19:13
  • Akshue there is an entire section in the code book covering pools but well before you get to these code has made it quite clear your case any location around a residence is going to require both a neutral and ground if you have both 120 & 240 , having separate feeds to the same location probably violates other code sections. The best thing to do would be to get a spa panel that could handle a couple additional GFCI breakers and feed the other devices from that panel. Using a 4 wire feeder.
    – Ed Beal
    Mar 16, 2021 at 19:25

2 Answers 2


If you need a 60A GFCI on a HOMeline panel, just get anybody else's panel as a subpanel, and install it right next to your main panel (or wherever you please). It can be any size of panel you want, from a 70A 2-space clear up to a 200A 42-space if that would be convenient for other things. The run from main to subpanel must be 4-wire. The breaker must be appropriate for the wire and <= the subpanel's ampacity.


The answer to both A & B is NO. The only place the ground and neutral can be tied together is in the main panel if under the NEC.

There is a 3rd way pull 4 wires.

Not wanting to pull a 4th wire would be a very shaky legal defense if someone bootlegs a ground and there is an injury.

If you only power a 240v load a neutral is not needed and that 3rd wire can be your ground but no tying neutral and ground together.

  • Thanks for the info. I’ll plan on adding the GFCI in the basement as basically a sub panel. (Feel kind of silly - with a heat pump, it’s not required via NEC)... out of curiosity - why can I not use the neutral from one of the other circuits nearby? The 240 has no neutral - the only reason to add a neutral is to power the monitoring stuff of the GFI.
    – Akshue
    Mar 16, 2021 at 22:45
  • @Akshue -- are these wiring runs in cable or conduit? Mar 16, 2021 at 23:34
  • The wire has to be in the same cable or conduit, the 17 code allows adding a separate ground but using a neutral from another circuit would violate several code articles other than the same cable. A pool heater is different than a heat pump and as of the 2020 code even heat pumps per 210.8.A all 125v through 250v receptacles require GFCI so now even a welding outlet or oven in the kitchen even require GFCI. pool equipment in article 680 even hardwired motors when replaced require GFCI protection electric heaters and 120v receptacles have required GFCI within 20’
    – Ed Beal
    Mar 16, 2021 at 23:40
  • Yes, conduit... this would be 1”, 24” down. Makes sense that they have to be in the same conduit, I guess. Will simply mount the disconnect inside the house and run the 3 wires for 240+gnd to the heater.
    – Akshue
    Mar 17, 2021 at 0:08
  • @akshue they have to be in the same circuit. You can treat safety ground like a generic common return busplane that everything goes back to. Can't do that with neutral because it carries normal service current. note that neutrals do NOT have breakers. Mar 18, 2021 at 8:17

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