Power out on 1 circuit only: the 5 causes

1. A tripped safety switch or circuit breaker

Open the switchboard. Modern boards have circuit breakers (small switches with a number on them) and safety switches (RCDs, usually with a test button). A tripped one sits in the middle or off position. Push it fully off, then back on. If it holds, that's the fix, but note what was running when it tripped, because it tripped for a reason.

2. An overloaded circuit

A heater, a kettle and a toaster on the same kitchen circuit can pull more than the breaker allows, and the breaker does its job. If the trip happened while several big appliances were on together, spread them across other outlets and reset. If it's a regular event, the circuit needs to be split or the board needs more ways. That's a switchboard job, not an emergency.

3. A faulty appliance

The most common cause of a safety switch that keeps tripping. Unplug everything on the dead circuit, reset the switch, then plug things back in one at a time. The one that trips it is the one that's faulty, and it usually has a damaged lead or moisture inside. Fridges, old heaters, irons and anything that's been rained on are the usual suspects.

4. Water in an outdoor fitting

If the trip happened during or after rain, suspect an outdoor light, an external power point or a garden pump. Water gets into a fitting, bridges live to earth, and the safety switch trips, sometimes hours later as it dries and re-wets. You can't fix this one from the switchboard. It needs the fitting opened, dried and tested, or replaced with one that's properly rated for the weather.

5. A failed connection on the run

Wiring doesn't wear out, but connections do. A loose neutral in a junction box, a power point that's been overheating, a cable damaged by a rodent in the roof or a screw through it during renovation: any of these can kill part of a circuit. The tell is that the breaker won't reset even with nothing plugged in, or that some outlets on the circuit work and others don't. This is fault finding work: a tester, a method, and an electrician who's done it a thousand times.

What to do right now

1. Switchboard. Reset anything tripped.
2. If it trips again, unplug everything on that circuit and reset once more.
3. If it holds, plug things back one at a time to find the appliance.
4. If it trips with nothing plugged in, or won't reset, leave it off and call.
5. If there's any burning smell, buzzing or a warm switchboard, leave it off and call now.

We do urgent fault calls across Adelaide from 6am, Monday to Friday. When you call, tell us what's dead, what tripped and what you've already tried. It usually gets the fault found in the first hour.