Why Air Conditioners Trip Circuit Breakers

By Dave Rongey - Summary:

Air Conditioner Units and Tripping Circuit Breakers: The circuit that an air conditioner is connected to may be shared with other outlets so the circuit is becoming overloaded, here is how to solve this problem.

Air Conditioner Electric Circuit

Electrical Question: I live in an NYC apartment with two roommates and this apartment, though spacious, is really inconvenient. We have a window Air Conditioner (AC) set up in the living room but it only cools down that room and the kitchen, not the little hallway leading into our bedrooms.

  • We all have portable AC units in our room for that, but whenever I try to turn on my portable AC, the window AC also goes off after a minute or so, we noticed that the circuit breaker keeps popping/tripping so we go back and reset it. However, only the window AC automatically turns back on, while my portable AC does not. If I try to turn it back on, it runs for a minute again and then shuts off, popping the circuit breaker switch again. My roommate’s portable AC is able to run at the same time as the window AC, and the other roommate’s portable AC is on a different circuit (fairly certain since she never seems to have problems with it shutting off), so right now I’m the only one without AC and it is sweltering in this NYC heat.
  • The switch that keeps popping says it has 15 amps on it. The window AC is 11,000 BTU and my portable AC is 10,000. There’s a bunch of other 15 amps switches and 2 other longer/bigger looking switches that say 40 amps on them. Is it overloading on that one 15 amp circuit? Yesterday, I tried turning off the window AC to turn mine on, but it still tripped the circuit.
  • However, tonight I turned my portable AC on with the window AC running and it is working. My roommate’s portable AC is off though so I think maybe that all three AC units can’t run at the same time?
  • I contacted my landlord who said he would send his repairman over to look at it soon but he’s slow with these things so I don’t know how soon that will be. What exactly can be done in this situation… is it possible to somehow rewire the circuit so that one of our AC units can go onto a different circuit and everyone can have their AC units on?

This electrical question came from: Stacy, from New York, New York.

Dave’s Reply:
Thanks for your electrical wiring question Stacy.

Air Conditioner Tripping the Electrical Circuit

Portable Air Conditioner Units and Electrical Circuit Requirements

  • As described in this question, the circuits that the air conditioners are connected to are shared circuits that are becoming overloaded which is causing them to trip off.
  • This typically happens when a portable or window air conditioner is plugged into an outlet circuit that may be shared with other outlets, so the circuit can become overloaded and cause the circuit to trip off.
  • A dedicated circuit should be installed for each window air conditioner which will prevent the room outlets from becoming overloaded.

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4 Responses to “Why Air Conditioners Trip Circuit Breakers”
  1. Dave Rongey says:

    Hi Kath,
    Sorry to heard about your air conditioner problem. I would suggest letting the unit sit for a while after resetting it, then turn it back onto a lower setting. The hot days that we have been having are placing quite a strain on many AC units, so they may have a hard time keeping up with the heat if they are set to full cooling. If the unit continues to trip off then go over the list in the article above which may help you diagnose the problem.

  2. kath whitaker says:

    I have an air conditioner unit that vents with a hose to the window. It worked great, but has now shut off. I reset the unit but it does not go on. Whats up with this?

  3. Dave Rongey says:

    Hi Waverly,
    When a circuit does not have power I begin by checking by checking for a tripped circuit breaker. If that is not the problem then I identify the circuit at the panel and shut it off and begin checking in the junction boxes of the outlets to look for a bad connection. See the information in the Troubleshooting Section for more information.

  4. waverly says:

    I have a living room and a bedroom that have no power, where do I start to fine the problem?


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