enter image description hereenter image description hereenter image description hereCan I add a sub panel feed off my 200A service box? If so what are the requirements?

Or would I need to run it from the main house breaker inside the house and wire from there? I currently have a 125amp? subpanel right next to my service box on the side of my house. But it is wired not into the lugs, but into a 50 amp breaker that says "backfeed do not touch" for that breaker..

This subpanel is for an inground pool and I was going to add a heat pump to it.

Want it to be safe, but not spend a fortune or alot of work.

  • 3
    Can you post photos of all panels involved? May 19, 2019 at 1:16
  • See photos i forgot to mention I am trying to add a 70 amp 240v heat pump to this setup May 23, 2019 at 15:42
  • Can you figure out what gauge the tap wires running to the outside subpanel are? May 23, 2019 at 22:23
  • A picture of your indoor panel would be useful too -- since the feed to your outdoor panel is tapped off of the same feeder, how much is being used by the other panel is an important consideration. Plus, adding a 70A 240V load to a 200A service is a lot, so it's also a good idea to check that we won't be overloading your main breaker.
    – Nate S.
    Feb 12, 2021 at 16:35

2 Answers 2


I don't think that's a 125 amp wire. My bet is that's an 8 gauge wire feeding that whole panel, so 50 amps per leg. I wouldn't bank on it being more than that.

Whether or not you can add more is another question. You've got a 20 amp 240v breaker and a 20 amp 120v breaker. You could add another 20A to the one leg with only 20A (the unused slot below the single 20A) and be OK. You just can't exceed 50A on any given leg.

  • Depends on the actual loads, perfectly normal to have "sum of branch breakers" larger than "main breaker" on most panels, so while 50A draw cannot be exceeded (without changing wire and input breaker, though I do have to question if that tap setup is legit anyway, as it stands, since it appears to put 200A onto the probably 8 gauge wires leading to the 50A backfeed/main), you might (depending on actual loads) be just fine adding another 20A 240V breaker.
    – Ecnerwal
    May 23, 2019 at 14:25
  • Yeah, that saddle joint doesn't look kosher to me either.
    – Machavity
    May 23, 2019 at 14:45
  • Would you suggest that I run higher gauge wire back from the main circuit breaker panel in the garage back outside to this subpanel to fix this and handle the additional 60amp load? May 23, 2019 at 15:32
  • I am trying to add a 240v 70amp max heat pump to this setup somehow. May 23, 2019 at 15:40
  • 1
    Yeah, it's generally not a good idea to have a breaker higher rated than the incoming breaker. So it would be a good idea to upsize to 100 amp and 2 gauge THHN (will require a conduit upsize). I would also feed it off your main panel and not try to reuse that weird (and possibly not code) saddle attached to the main
    – Machavity
    May 23, 2019 at 15:50

The current wiring does not appear to violate any codes as the 10 Foot Tap Rule allows such an installation. With that said I would advise going away from using any further taps as it can be a headache in the future. The best solution would be to replace the Meter/Main Panel with a Panel having space for more than just the main breaker. This will give you almost unlimited options for future exterior power requirements (Future Car Charger??). However that would be costly, require the involvement of your utility company and require a shutdown of all power. If you are not willing to go to that expense/trouble then I would suggest connecting to your interior breaker panel or your outdoor sub panel so long as your new load doesn't exceed about 30 Amps.

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