Which appliance is tripping the power in my home?

Which appliance is tripping the power: how to find out

When the power goes off suddenly, there is almost always an appliance behind it. Before unplugging anything, look at which switch has dropped in the fuse box (consumer unit), because each one points to a different problem.

First, check what has tripped

• The RCD (diferencial, the switch with a TEST button): current is leaking to earth. Usually an appliance with damp or damaged insulation.
• An MCB (magnetotérmico, the small breaker for each circuit): overload or short circuit on that circuit. A faulty appliance, or too many powerful ones at once.
• The power control switch (ICP): you have gone over your contracted power (potencia contratada). It is not a fault, just the sum of what is running.

The one by one test

1. Unplug every appliance you can.
2. Reset the switch that had tripped.
3. Plug the appliances back in one at a time, leaving a couple of minutes each and, if possible, running them: the water heater (termo) heating, the washing machine on a hot wash.
4. The one that trips the switch is your suspect. Repeat the test to confirm it.

Some faults only appear when the appliance heats up or its motor starts, so the fridge or the air conditioning may take a while to give themselves away.

The appliances that fail most

• Electric water heater: limescale wears the heating element until it leaks to earth.
• Washing machine and dishwasher: heating elements, pumps and damp in the connections.
• Oven and hob: elements and cables that suffer from the heat.
• Fridge: damp in the defrost circuit.
• Outdoor equipment: awning motors, pumps or terrace lights after rain.

When it is not a single appliance

Sometimes the RCD trips without any one appliance being faulty: the small leaks from lots of electronic devices add up and are enough to trip it. And if it still trips with everything unplugged, the leak is in the wiring.

What a diagnosis costs

Measuring the insulation of your appliances and circuits has a guide price of 70 to 100 euros. The reading tells you whether the appliance can be repaired or is better replaced.

When to call an electrician

Call if you cannot find the appliance, if it trips with everything unplugged or if an appliance gives you a shock. In Seville, Spain, we diagnose this on our appliance tripping the power page, and urgent cases on RCD keeps tripping.