If your circuit breaker keeps tripping or your safety switch keeps cutting out, something is wrong and you need to find it. Most people try resetting it a few times and hoping. Here is what actually causes repeated tripping and how a sparky tracks it down.
What is the difference between a tripping breaker and a tripping safety switch
A circuit breaker trips because the circuit is drawing too much current. This is usually because too many appliances are on, or one appliance is faulty and drawing more than it should.
A safety switch (RCD) trips because there is current leaking somewhere. This is usually a problem with insulation in a cable, a faulty appliance, or moisture getting into something it should not.
Step 1: figure out what circuit
If it always trips when you use the same appliance, that appliance is probably the cause. Test by unplugging it and seeing if the trip stops.
If it trips at random times, it is more likely a circuit-wide issue.
Step 2: isolate and test
Turn everything off on that circuit. Unplug all appliances. Turn all the lights off. Reset the breaker.
Then turn things back on one at a time. The thing you turn on right before it trips is your culprit. This is the same approach an electrician uses but they have meters that can do it faster.
Common causes of repeated tripping
Old appliances (kettles, toasters, fridges) with degraded heating elements that leak current.
Hairdryers and electric razors used in bathrooms where moisture is everywhere. Bathroom RCDs are sensitive.
Outdoor lights or power points that have had water get into them.
Pool pumps, especially old ones.
Damaged extension cords or power boards.
In rare cases, damaged cables inside walls (from past renovations, nail strikes, or general age).
What an electrician does
Insulation resistance test (megger test) on the affected circuit. Measures whether the cable insulation is intact or degraded.
Earth fault loop impedance test to confirm the safety switch will trip when it needs to.
RCD trip test to confirm the actual trip current and trip time meet spec.
Visual inspection of the switchboard, any accessible junction boxes, and the appliances on the circuit.
What it costs
Standard fault-finding callout: $180 to $350. Includes the testing above and a clear diagnosis.
Repair costs depend on what is found. Replacing a faulty RCD: $150 to $250. Repairing a damaged cable in a wall: $400 to $1,500 depending on access. Replacing a faulty appliance: just the cost of the appliance.
When it is urgent
If your power is tripping at random and you cannot identify the cause, call an electrician sooner rather than later. Most repeated tripping is harmless but a small percentage is the early warning of something more serious. Worth the cost of a callout to be sure.