Why your window, wall, or portable is tripping (5 reasons+fixes)

Are you frustrated that your air conditioner is not cooling your apartment or RV during the hot summer?

Is your air conditioner repeatedly tripping, sometimes randomly for a yet unclear reason?

In this post, I will explore the 5 common reasons why your air conditioner may trip and suggest possible fixes to the problem.

Note: They are arranged in order of the most common to (hopefully) help you narrow down the likely cause of the tripping faster.

# 1. Your AC’s electrical circuit may be undersized

Confirm that the AC is connected to a suitable circuit breaker rating

If your AC’s breaker is tripping, confirm that it is connected to the recommended circuit breaker size according to the manufacturer’s technical specifications.

If it is lower than the recommended circuit breaker rating, then your AC may trip repeatedly as the cooling load increases for example, during hot weather.

Your AC should be connected to a suitably sized electrical circuit

Also, check that the AC is connected to an electrical circuit whose wiring size matches the manufacturer’s recommendation. Check out our guide on circuit breaker and wire sizes for air conditioners.

Your circuit breaker may trip if the AC is connected to a higher wire gauge (bigger AWG ) increasing the likelihood of a fire.

Dedicated vs shared electrical circuit

Is your AC connected to a dedicated electrical circuit or is it connected to a circuit with other appliances?


If the AC is connected to an electric circuit shared with other appliances, make sure that the combined appliance load does not exceed wire and circuit breaker size.


If it is a shared circuit with other appliances such as a heater or kettle connected, it is possible to overload the electrical circuit and trips the circuit breaker.

Consider connecting your AC to a dedicated, well-sized electrical circuit.

# 2. Bad electrical wiring connecting your AC

Loose wire connections

Tripping of the circuit breaker can also be caused by loose wire connections at the electrical panel.

These can cause sparking, overheating of the wires tripping the circuit breaker.

Damaged insulation and short-circuits

Weak or damaged insulation caused by moisture, excessive heat, or physical impact can result in short circuits that trip the circuit breaker.

You may be able to tell that it is a case of bad wiring when you smell burning insulation before or after the tripping of the circuit breaker.


Another sign of possibly damaged wiring is when the circuit breaker for the AC trips immediately after a reset.

Fixing the faulty wiring (get a certified electrician) may require any of the following:

  • tightening the wire connections in the electrical panel to eliminate sparking
  • replacing the damaged wire, to stop the electrical short-circuit.

Faulty circuit breaker

Sometimes breakers can fail due to overuse or poor quality.

Are you able to monitor the amount of current drawn by the AC’s using a clamp meter as soon as it is switched on or right before it trips the breaker?

If the current draw is well below the breaker rating when the breaker trips, consider replacing the breaker.

# 3. Sometimes the AC’s compressor trips the breaker on restart after power outage

You may experience tripping of the AC”s circuit breaker immediately started after a power outage.

This is usually caused when the AC’s compressor attempts to overcome the high head pressure but fails because of the low initial starting torque of the compressor – drawing high currents in the process.


To prevent this, you may:

  • allow for 5 mins or so for the compressor pressure to balance out before starting the AC after experiencing a power outage
  • install an on-start delay when the AC is switched on to allow any head pressures to balance out reducing the chances of the breaker tripping on restart.

# 4. You have a faulty AC

Your circuit breaker may also trip because of a faulty compressor or electrical fault within the AC.

When this happens your AC may not turn on completely or may turn on briefly before tripping the breaker.

Either way, you need your AC to be checked out by certified electrical personnel.

# 5. Your AC needs servicing

Blocked heat exchanger coils in the AC because of lack of servicing can put an extra load on the AC and cause it to trip.

Is your AC not cooling well? Is your AC starting but after a few minutes (~5min) tripping the circuit breaker?

This may be a case of lack of service. Check when your AC was last serviced.

If not recently, you may need to arrange for your AC to be serviced.

All in all, if your AC is tripping the circuit breaker, this may be caused by undersized or faulty wiring. Check that its wiring is properly sized and that it is not faulty. You may also need to have an on-delay timer installed in some cases for ACs that trip the breaker on restart after a power outage.

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