Why Your Safety Switch Keeps Tripping

A light goes off in half the house, you walk out to the meter box, and one switch is sitting down in the off position. You push it back up and it holds for a day, then it drops again. That is not a temperamental switch. It is a protective device doing its job.

Safety switch or circuit breaker

Open the meter box door and look, without touching anything else in there. You are looking for which sort of device moved.

A safety switch, also called an RCD, has a test button on the front and "30mA" printed on it, according to Energy Safe Victoria's household wiring guide. A circuit breaker has neither.

Energy Safe Victoria describes a safety switch as monitoring the flow of electricity through a circuit and detecting problems that may pose a risk to personal safety, then cutting the power within milliseconds. Its household wiring guide puts that at 0.03 of a second. It is watching for current escaping the circuit, which in the worst case means current travelling through a person.

A circuit breaker is not doing that job. Energy Safe Victoria is clear that it provides short circuit and over current protection, such as when a powerpoint is overloaded, and that breakers and surge diverters do not protect a person against electric shock.

So a breaker that trips is usually telling you the circuit is carrying too much. A safety switch that trips is telling you current is going somewhere it should not. Note which one is down and which part of the house went dark, because it is the first thing an electrician will ask you.

The common reasons one keeps tripping

Most repeat trips fall into a few groups:

• A faulty appliance leaking current to earth. Ageing heaters, kettles, fridges, and washing machines are frequent offenders.
• Water where it should not be. Late winter rain finds its way into outdoor powerpoints, garden lights, shed circuits, and pool equipment.
• A damaged lead or plug. Energy Safe Victoria warns never to use an appliance with a frayed cord or a cracked or broken plug, and says damaged cords should be replaced or the appliance disposed of.
• A fault in the fixed wiring, which is not something you can see from the meter box.

A pattern is a clue. If it only goes when it rains, or only when the dryer runs, write that down.

How to narrow it down to an appliance

There is a safe version you can do yourself. Energy Safe Victoria sets out the same order for restoring power after an outage: unplug appliances first, then turn on each breaker one at a time.

• Unplug everything on the affected circuit. Not just switched off at the wall, unplugged.
• Reset the tripped switch at the board.
• Plug appliances back in one at a time, giving each a few minutes and running it if you can.
• When the switch trips again, the last thing you plugged in is your likely culprit.

Stop there. Do not open the appliance and do not try to repair it. Energy Safe Victoria states that only a qualified repair technician or a licensed electrician can repair appliances, and that doing electrical repairs yourself is unsafe and illegal.

When to stop and call a licensed electrician

Some situations are not fault finding exercises:

• The switch will not reset, or trips again the instant you reset it.
• There is a burning smell, a scorch mark, or a buzzing or crackling sound at the board or a powerpoint.
• Anyone has felt a tingle or a shock from an appliance or from a tap. Energy Safe Victoria says to call your electricity company immediately if that happens.
• The safety switch does not trip when you press its test button. Energy Safe Victoria's advice there is to call a licensed electrician immediately to investigate.

Energy Safe Victoria's Test. Reset. Protect. campaign asks you to check your safety switches every three months by pressing the test button on each one. If the power does not go off, the device is not protecting anything.

Older boards make this harder

Plenty of older homes around the Peninsula and the bayside suburbs still run a board where one safety switch covers a couple of circuits and ceramic rewirable fuses cover the rest. Half the house has personal protection and half has none. It also makes fault finding slower, because one device covering that much of the house tells you little about where the problem is.

Energy Safe Victoria notes that fire brigades respond to more than 300 domestic electrical fires each year, and that many are caused by old wiring that has degraded or is unable to cope with the demands of modern electrical equipment. It advises that if your house was built more than 30 years ago, the wiring should be checked.

What to do next

Work out which device tripped, look for the pattern, and run the unplug and reset test if it is safe to do so. If the switch will not hold, if nothing is plugged in and it still trips, or if you can smell or hear something wrong at the board, call a licensed electrician. Repeat tripping is information, and it is worth chasing down rather than living around.