Why does my air conditioner keep tripping the breaker?

An air conditioner that keeps tripping the circuit breaker or safety switch has an overload or an electrical fault, such as a failing compressor, damaged wiring, water getting in, or a worn breaker. Repeated tripping is a warning. Stop using the unit and have a licensed electrician or air-conditioning technician find the cause.

What is the difference between a breaker and a safety switch?

A circuit breaker protects wiring from overheating by cutting power when too much current flows. A safety switch (also called an RCD, or residual current device) protects people by cutting power quickly if electricity is leaking to earth, for example through a person or through water. When a safety switch trips, it means something is leaking current, and that is taken seriously. Our guides on a tripping breaker and a tripping safety switch explain these in more detail.

Why would an air conditioner trip them?

• An overloaded circuit. The air conditioner shares a circuit with other loads, or draws more than the circuit can supply.
• A compressor or motor fault. Worn windings can draw high current or leak current to earth.
• Damaged wiring or loose connections. These can overheat or arc.
• Water getting into electrical parts. Leaks, storms or damaged seals can cause earth leakage.
• An ageing breaker or safety switch. These devices can wear and trip below their rating.

Some units draw a surge of power when they start, which is another reason the supply and the circuit need to suit the unit. Only a licensed professional can judge this.

Why is repeatedly restoring power a bad idea?

The device is doing its job. Repeatedly forcing power back on can overheat wiring, damage the unit or put people at risk of shock. Do not try to reset, bypass or replace the breaker, safety switch or isolator yourself.

Who does what?

The electrical connection and the circuit are the job of a licensed electrician, and Electrical Safety Office Queensland regulates electrical work in the state. Refrigerant and the internal workings of the unit are the job of an ARC-licensed technician. Some faults involve both, which is why it helps to describe exactly what happened. You can check any electrician’s licence online before you book.

Could it be the switchboard rather than the air conditioner?

Yes. An old or overloaded switchboard, or a breaker or safety switch that is wearing out, can cause nuisance tripping even when the unit is fine. An electrician can tell the difference.

What happens on the visit?

The electrician will inspect the circuit, the protective devices and the connection, and test them with proper equipment. They will liaise with an air-conditioning technician if the unit itself is at fault.

What if it only happens occasionally?

An occasional trip is still worth reporting. Intermittent faults, such as a slowly failing part or moisture getting in during wet weather, tend to get worse over time. Write down the date and conditions each time it happens so the electrician has a pattern to work from.