I'm the recent owner of a 27yr old house. I'm looking to find more power for the basement that I'm finishing. There's a 50A circuit going to one of the outdoor AC units - but the info sticker on that unit says it should be connected to a 15A breaker only (if I'm reading it right).

The 50A breaker is in the 2nd image - top left.

The question is - can I just replace the 50A breaker w/ a 15A (double one) and leave the heavy gauge wire in place? If so, is this a simple swap?

Alternatively, I'd prefer to actually run that 50A to a subpanel & use that to split the basement into 3 zones, but if I did that I don't know how I'd power the A/C, since it requires 2 slots (and the entire panel is full). Breaker Panel Outdoor A/C Unit

  • 2
    Most ACs require a disconnect within line of site of them, and many disconnects have fuses inside. If that's the case, and the fuses are 15A, the setup is probably fine as-is.
    – Nate S.
    Nov 1, 2019 at 20:57
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    Looks like the stove is on the 50 amp breaker and the AC is on a 40 Amp breaker...
    – JACK
    Nov 1, 2019 at 21:16
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    If the AC is on the breaker marked "Stove", then what's on the breaker marked "Air Cond"? The stove? Another air conditioner? Nothing? Something else? Also, can you post photos of the air conditioner's service disconnect, including the labeling? Nov 1, 2019 at 22:48
  • 5
    What I see is a 50 amp breaker that has been overheated in the past. I would be pulling the dead face and inspecting the wiring. I would also be verifying what breakers supply the devices as even my phone display shows the stove on the 50 and the AC on the 40 and the op is correct the max breaker for the outside unit is 15 amps that’s tiny for an r22 system
    – Ed Beal
    Nov 2, 2019 at 2:58
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    @EdBeal -- good eye! That 50A breaker does look to have sustained a bit of heat damage at some point, yes... Nov 2, 2019 at 5:08

1 Answer 1


why not use the 50 amp for sub panel then come off the sub panel and feed the AC with 15 amp. You would then have 35 amps for basement circuits.

  • 2
    You use actual loads (or sometimes nominal loads) when computing feeder loading, not breaker sizes... Nov 2, 2019 at 4:12

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