I purchased a mini split A/C unit with 20-amp double pole breaker. I ran 20 feet of 12-gauge wire outside to my Siemens Fuseless quick disconnect box, which came with flex conduit and 10-gauge wire.

Is it OK to run the 10-gauge wire to my condenser, which is two feet from my disconnect?

The label on my mini-split has this information on it:

outdoor fan motor load 0.3a compressor load 8.7amps. max fuse breaker (HACR) 20 A power source 208-230v-60Hz, 1PH

  • It is okay, but does not sound right. 10g is used for 30 amp service/circuits. Why give you 10g if on only 20 amp breaker? A/C unit should have a small plate listing it's amperage needs. Should check that first.
    – crip659
    Jul 20, 2021 at 22:39
  • Probably a single kit shipped for all units up to 30A, not worth their effort to stock kits that the only difference is short pieces of wire. Be sure your breaker does not exceed "Maximum Overcurrent Protection" on the unit label. Jul 21, 2021 at 0:46
  • 1
    Can you post photos of the nameplate on the outdoor unit for your minisplit? Jul 21, 2021 at 1:04
  • won't let me photo to large label states outdoor fan motor load 0.3a compressor load 8.7amps. max fuse breaker (HACR) 20 A power source 208-230v-60Hz, 1PH
    – Ron Kesti
    Jul 22, 2021 at 21:47

2 Answers 2


It's fine to run the 10 ga wire. Not needed and harder to work with than 12 ga, but it's OK.

But the other issue I see here is a "fuseless disconnect". Everytime I've hooked up a minisplit or heat pump, they require actual fused (not circuit breaker) disconnects. You should check with the manufacturer to see if that's a requirement for your unit.

EDIT based on crip659 comment: Also, be sure what the electrical requirements are for the unit. The installation instructions or nameplates should give you that. He's right in that a 10 ga whip suggests a 30 amp circuit. If its 20 amp, you're ok, if not, you have another cable to run.

  • The OP says the disconnect came with flex conduit and 10 gauge so if it's a 30 Amp disconnect, 10 gauge would be what to include. +1
    – JACK
    Jul 20, 2021 at 23:21
  • 2
    BTW: if the nameplate says "Max Fuse" then fuses are required, if it says "Max Overcurrent Protection" or "Max OCPD" or just "MOP" then you can use a fuse or a breaker Jul 21, 2021 at 1:05
  • My mini-splits don't call for a fuse.
    – Ecnerwal
    Jul 21, 2021 at 2:37
  • @Ecnerwal Just FYI, in my son's new house build, the installer wanted the mini-split outdoor to be protected by actual fuses. Jul 21, 2021 at 13:10
  • My Mitsu minisplit is on breakers inside; haven't checked what's in the outside switch.
    – keshlam
    Jan 8, 2023 at 8:44

Yes its ok to run the last section on 10AWG. You can oversize the wire, you just can't undersize it and cause it to overheat and start a fire.

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  • This doesn't add any information that isn't already included in other answers.
    – JACK
    Jan 8, 2023 at 19:31

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