Do not keep resetting it
A breaker trips to protect wiring and equipment from too much current or from a fault. If it trips again soon after you reset it, something is wrong. Repeatedly resetting it can overheat wires or damage equipment, and in the worst case can create a fire hazard. If a breaker trips more than once, leave it off and get the problem diagnosed. If the system is newly installed, contact the installer first, as the work may be covered by a warranty or workmanship guarantee.
Why a new heat pump trips a breaker
A newly installed system has a few extra possibilities beyond the usual wear-and-tear problems.
Wrong breaker size or type
Heat pumps are designed for a specific circuit rating. The unit’s nameplate typically lists the minimum circuit ampacity and the maximum overcurrent protection allowed. If the breaker is too small, it can trip under normal load, especially at startup. If it is too large, it may not protect the wiring and equipment. Never swap in a larger breaker to stop the tripping. Have a qualified electrician or the installer verify the correct size and type against the nameplate and local code.
Wiring problems
Loose connections, undersized wire, or a wiring error can cause heating at terminals and nuisance trips. Poor connections are a real hazard because they can overheat. A qualified electrician should inspect the connections at the panel, disconnect and unit.
Short to ground or damaged wire
A nick in insulation during installation, a pinched wire, or water getting into a connection can cause a ground fault or short circuit, which trips the breaker quickly, sometimes immediately. Do not inspect wiring inside panels yourself.
Shared circuit or wrong circuit
A heat pump usually needs its own dedicated circuit. If other loads share it, or if the wrong circuit was used for the indoor unit or backup heat, the combined load can trip the breaker. Many systems also have separate breakers for the outdoor unit and the indoor air handler with electric heat strips, so make sure you know which one is tripping.
Equipment fault: capacitor, compressor, fan motor
New equipment can still have faulty parts. A failing capacitor, a compressor drawing too much current, or a seized fan motor can all trip the breaker. These are high-voltage components and need professional diagnosis.
Airflow or overheating
Heavy airflow restrictions, such as a clogged filter or blocked outdoor coil, make the system work harder. This is less common right after a new install but possible, especially if the ductwork or filter is the problem. Our guide on a heat pump that won’t cool lists airflow checks. A system that is short cycling can also stress the electrical system, see short cycling.
Safe things to check
- Note which breaker trips (outdoor unit, indoor unit, or backup heat) and when: right away, after the compressor starts, or after running for a while.
- Replace a dirty air filter and make sure vents are open.
- Make sure the area around the outdoor unit is clear.
- Check whether the thermostat is working properly. See thermostat troubleshooting.
- Write down what you observe to share with the installer.
What not to do
- Do not replace the breaker with a higher-rated one.
- Do not tape the breaker or otherwise hold it on.
- Do not open the electrical panel or the unit’s control box unless you are qualified.
- Do not keep running the system if you smell burning, see scorch marks, or hear popping or buzzing.
What an installer or electrician will check
They may confirm breaker rating against the nameplate, wire gauge, terminal tightness, disconnect, grounding, insulation condition, and compressor and motor current draw. They can also test components like the capacitor and contactor.
When to call
Call the installer or a licensed electrician or HVAC technician if the breaker trips more than once, trips immediately, feels hot, smells of burning, or if you can’t tell why. If you see smoke or fire, leave the area and call emergency services.
FAQ
Why does my breaker keep tripping on my heat pump? Common causes are the wrong breaker size, wiring faults, a failing component, or overheating from airflow problems.
Is it bad to keep resetting a breaker that keeps tripping? Yes. It means there is a fault, and repeated resets can be unsafe.
Why would a 20-amp breaker keep tripping with nothing plugged in? A fault in the wiring, a faulty breaker or a ground fault could be responsible. Have an electrician investigate.