Why Does My Aircon Keep Tripping The Breaker?
Breaker trips with a burning smell point to a short circuit, sustained overcurrent, or heat damage at a wiring point. The trip timing, instantly versus after a brief hum, separates the cases.
1. Current Leak Or Short Event
How This Works
A current leak happens when electricity takes an unintended path to ground: through degraded wiring insulation, moisture-contaminated terminals, or a compressor winding tracking current to the motor casing. The breaker senses this earth fault and trips within milliseconds, often before the unit completes a single startup cycle. With an RCD, even a few milliamps triggers it.
How To Tell
The breaker trips almost immediately, often within seconds of startup. Unlike startup overcurrent, the unit does not hum first; the trip cuts in before the motor draws inrush. If the timing is the same on every attempt and the unit never settles into a run, insulation testing should come before any restart.
- Breaker trips immediately or soon after startup.
- Trip pattern repeats across restart attempts.
- Unit cannot sustain a normal run cycle.
- Trips correlate with rain or worsen after wet weather.
How We'd Confirm It
We shut power, measure insulation resistance on the compressor and wiring to find the leak path, replace damaged parts, and confirm a safe restart.
Stop resetting the breaker. Each reset drives current through a degraded insulation path and increases the risk of a hard short or arc event.
2. Startup Overcurrent Under Load
How This Works
Every motor draws more current at startup than during steady operation. The breaker tolerates this brief inrush. When the run capacitor weakens, the compressor no longer gets the phase-shifted boost it needs for a clean start. It draws sustained high current in a locked-rotor condition, attempting to spin against full refrigerant pressure without the assistance it requires.
How To Tell
The breaker trips after the unit hums briefly. There is a short window where the motor draws inrush current before protection activates. Unlike a current leak, which trips almost instantly, the unit was reaching the startup phase before the breaker cut in. On hotter days or after warm restarts, the trip may be more consistent.
- Trip happens during startup surge.
- Unit hums briefly before breaker trips.
- Runtime stays brief and unstable.
How We'd Confirm It
We shut power, clamp-meter the startup current draw, and check the capacitor and motor windings to identify the overloaded component.
Do not force repeated restarts to test whether the trip recurs. Each failed startup under a stressed compressor or weak capacitor accelerates winding damage and can convert a recoverable fault into a compressor replacement.
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