The portable ac in one room trips the 15 amp circuit breaker after about 45 minutes, can the breaker safely be changed to a 20 amp breaker?

  • 1
    Does it trip the breaker instantly, or after some time has passed? What other loads are on the circuit? Sep 8, 2019 at 23:00
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    "after about 45 minutes" == after some time has passed Sep 8, 2019 at 23:03
  • I really hope there isn't a temperature controlled heater on the same circuit... The power drain on an AC should be higher when it is first turned on, so it's kind of odd it trips only after 45 minutes.
    – Nelson
    Sep 9, 2019 at 2:03
  • Hello, and welcome to Home Improvement. Interesting question; keep 'em coming. And, you should probably take our tour so you'll know how best to participate here. Sep 9, 2019 at 12:42

3 Answers 3



The breaker size is dependent on the wire size. If the wire was 12 AWG then it would most likely already have a 20 Amp breaker. Since it has a 15 Amp breaker, most likely at least some of the wire in the circuit is only 14 AWG.


Never. Of course not. If the building had been built with 20A wiring, they would've just used a 20A breaker in the first place. They cost exactly the same as 15A breakers.

Anyway, if the appliance was supplied with a standard 15A plug (parallel prongs, you know the one), then it definitely works on a 15A circuit. UL would not have given it a listing otherwise. In fact, air conditioners typically draw around 4-8 amps, and you've got 15.

The real problem is something else on the circuit.

Or, the "something else" being run at the same time as the air conditioner, and together they are exceeding 15A. You will know where to look for the "something else", because it too loses power when the air conditioner goes.


You cannot go from a 15 amp breaker to a 20 amp breaker unless you confirm the wire feeding the circuit is #12 AWG. The wire installed is probably #14 AWG and it's maximum rated amperage is 15. If you have a ability to replace the wire to #12 AWG, you can replace the breaker to a 20 amp. You would want to then replace the outlet to a 20 amp outlet. What does the name plate for the ac say about amperage for the unit?

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