Cause 1: Earth leakage (the most common)
If the main earth leakage unit trips (the larger trip switch labelled 'Earth Leakage'), current is leaking to earth somewhere. Common culprits: a kettle or washing machine with internal insulation breakdown, an outdoor circuit with water ingress, or a deteriorating earth leakage unit itself. An electrician isolates each circuit at the DB and uses an insulation tester to find the leaky one in 10–20 minutes.
Cause 2: Circuit overload
An individual breaker trips when its rated current is exceeded. Common on kitchen circuits with multiple appliances, geyser circuits with a failing element drawing high current, and air-conditioning circuits in summer. Solution: split the load across more circuits, or address the failing appliance.
Cause 3: Short circuit
Instant trip on a new circuit usually means a short — a damaged cable, a wrong wire connection, or water in a plug. These need diagnosis with insulation testing before re-energising.
Cause 4: Failing earth leakage unit
Earth leakage units wear out. After 8–10 years they can develop false trips or fail to trip at all. We test trip-time and trip-current with a calibrated tester to determine.
What you can safely do yourself
Switch off everything you've recently plugged in and reset the trip. If it holds, plug devices in one at a time to find the faulty one. If the trip won't reset at all, leave it off and call an electrician — the cause needs diagnosis with proper instruments.
FAQs
Need a Plumber or Electrician Today?
Owner-managed by Garth Blair. We pick up the phone and book you in personally.