Aircon Keeps Tripping? Why It Happens and What to Do
If your aircon keeps tripping the power, the electrical system is doing its job: something is wrong and it's cutting the supply to protect the wiring, the unit and you. Here's how to read the signs safely and who to call.
A trip isn't the fault itself. It's a safety device reacting to a fault. When an aircon keeps tripping, resetting it over and over without finding the cause can turn a small repair into a burnt component, or create a genuine safety risk. The first step is working out which device is tripping, because that narrows down the cause.
Earth leakage or circuit breaker: which one tripped?
Open your distribution board (DB) and look for the switch in the "off" or middle position. In most South African homes you'll find two kinds of protection, and they react to different problems.
| Point | Earth leakage unit | Circuit breaker |
|---|---|---|
| What it looks like | Usually a wider switch with a "test" button, often protecting several circuits | A narrower switch labelled with a current rating, one per circuit |
| What it watches for | Current leaking to earth, for example through damp insulation, a damaged component or a person | Too much current flowing in the circuit, from an overload or a short circuit |
| How sensitive | Very. Units protecting household socket circuits are typically set to trip at about 30 milliamps | Trips when current exceeds its rating for long enough, or instantly on a short |
| Common aircon causes | Water in the electrics, damaged cables, a compressor or fan motor leaking to earth | Compressor or fan struggling to start, a failed capacitor, an undersized or shared circuit |
Make a note of when it happens, too. Tripping the instant the unit starts, after twenty minutes of running, only on the hottest afternoons or only after rain all point in different directions, and a technician will want to know.
Common reasons an aircon keeps tripping
Water where it shouldn't be
Rain driven into an outdoor unit, or condensate overflowing from a blocked drain inside the indoor unit, can reach electrical parts and cause earth leakage trips. This often shows up after a storm or on humid days. If you've also noticed drips indoors, our guide on why an aircon leaks water explains the drain side of the problem.
Compressor faults
The compressor is the heart of the system and its largest electrical load. Damaged motor windings can leak current to earth, while a compressor that is seizing or struggling to start draws far more current than normal and trips the breaker. Compressor problems need proper diagnosis before anyone decides between repair and replacement.
Fan motor problems
Both the indoor and outdoor units have fan motors. A motor with worn bearings or failing windings can overheat, draw excess current or leak to earth.
A failed capacitor
On many units, capacitors give the compressor and fan motors the kick they need to start. When one weakens or fails, the motor strains to get going, draws high current and the breaker trips, often right at start-up. Capacitors hold a charge even when power is off, so this is strictly a technician's job.
An undersized or shared circuit
If the aircon trips its breaker mainly when the kettle, heater or microwave is also on, the circuit may be shared or too small for the load. An aircon should normally have a circuit of its own, sized to the unit's requirements. Our article on aircon electrical requirements explains what that involves.
Loose or burnt connections
Terminals can work loose over time, especially with vibration from the outdoor unit. A loose connection heats up, can start to burn and may eventually cause a short. Discoloured terminals or a burning smell are signs to switch off and call for help straight away.
Surge damage
Lightning and power returning after an outage can damage control boards and other electronics. A board that has been damaged by a surge may cause trips, error codes or a unit that won't start at all.
An overworked system
Dirty outdoor coils, a blocked airflow path or a refrigerant problem make the system run at higher pressures and draw more current, which can trip the breaker on the hottest days. Regular servicing keeps this in check.
What to do when it trips
- Switch the aircon off with the remote. Then turn it off at the isolator outside, if it has one.
- Look, don't open. Check for water around the units, scorch marks, melted plastic or a burning smell. If you find any of these, leave everything off and call a technician.
- Reset once with the aircon isolated. With the aircon's isolator off, reset the tripped switch in the DB. If it trips again straight away, the problem is probably elsewhere in the house, and that's a job for an electrician.
- Try the aircon once. If the DB holds, switch the aircon's isolator back on and start the unit. If it trips again, stop there.
- Write down what happened. Which switch tripped, how long the unit ran, any error code on the display and the weather at the time.
Aircon technician or electrician?
The answer depends on where the fault is, and sometimes you need both.
- Call an aircon technician when the DB only trips when the aircon runs, the unit shows an error code, there's water in the unit, or it trips at start-up or on hot afternoons. These usually point to a fault in the aircon itself.
- Call a registered electrician when the switch trips even with the aircon isolated, the circuit is shared with other appliances, the isolator or DB shows burn marks, or the circuit needs upgrading. Wiring and DB work, and the Certificate of Compliance that goes with it, are an electrician's responsibility.
If your aircon keeps tripping and the signs point to the unit, ARS can test it on site, find the cause and handle the aircon repair. If the unit is still under warranty, check the terms first, as in-warranty repairs may need to go through the manufacturer's appointed service agent. For anything else, book a repair visit or call 0861 995 092. When it can't wait, our emergency aircon repairs are available 24/7, including weekends and public holidays.
Tripping questions
Rain getting into the outdoor unit, its isolator or a damaged cable joint can create a path to earth and trip the earth leakage unit. Leave the aircon off until it dries out and have a technician or electrician find where the water is getting in, because the problem usually returns with the next storm.
An instant trip at start-up often points to a failed capacitor, a struggling or seized compressor, a shorted component or a circuit that is too small for the unit. All of these need testing by a technician with the right meters, so avoid repeated restarts in the meantime.
No. Occasional tripping is still a sign of a fault, and faults like loose connections or insulation breakdown usually get worse over time. Have the unit checked before the problem becomes a burnt component or a safety hazard.
Find the fault, not just the switch
ARS diagnoses and repairs tripping aircons on site across Gauteng.