Why Does My Fuse Box Keep Tripping? A London Electrician Explains

A fuse box that keeps tripping is annoying, and in the dark it is a little alarming. Here is the reassuring part. Nine times out of ten it is not the wiring trying to kill you, it is a safety device doing exactly its job, usually triggered by a faulty appliance or a circuit carrying too much. The trick is finding what is causing it, and you can often do the first bit of detective work yourself.

First, what is actually tripping?

Open the board and look at what flipped. A single circuit breaker, an MCB, dropping means that one circuit is overloaded or has a fault. The bigger switch, the RCD, cutting power to several circuits at once means it has spotted an earth fault somewhere.

That RCD is the hero of the story. Electrical Safety First describes it as a sensitive safety device that switches off electricity automatically if there is a fault. When it trips, it has almost certainly just protected someone from a shock. Frustrating, yes, but it is on your side.

Common reasons a fuse box keeps tripping

• A faulty appliance: kettles, washing machines, fridges and old chargers are repeat offenders
• Water getting in: a leak near a socket, or moisture in an outdoor light or socket
• An overloaded circuit: too many high power devices on one ring
• A damaged cable: a nail or screw through a wire during DIY is more common than you would think
• A failing heating element: immersion heaters and electric showers often trip as they wear out

How to find the culprit yourself, safely

If nothing smells hot and nothing looks damaged, you can narrow it down:

1. Unplug everything on the circuit that keeps tripping
2. Reset the breaker or RCD at the board
3. Plug appliances back in one at a time, waiting a moment between each
4. When it trips again, the last thing you plugged in is your likely culprit. Leave it unplugged and get it checked or replaced

Two hard stops. If the board trips again with everything unplugged, or you smell burning or see scorching, stop there. Do not keep resetting it. That points to a fault in the fixed wiring, and resetting repeatedly into a fault is not safe.

When to call an electrician

Bring someone in if the tripping keeps happening with nothing plugged in, if there is any burning smell or heat at the board, if it trips the moment it rains, or if you simply cannot find the cause. This is everyday fault finding work for us, and if you are left without power and it is not coming back, that is what our emergency electrician service is for, across every London borough.

Test your RCD now and then

While we are here, a quick habit worth keeping. Electrical Safety First recommends testing fixed RCDs about every three months using the test button on the board. Press it, the power should cut instantly, then switch it back on. If it does not trip when you press test, the device may have failed and needs looking at.

Frequently asked questions

Is it safe to keep resetting a tripped breaker?

Once or twice to test is fine. Repeatedly resetting into something that keeps tripping is not, because the device is telling you there is a real fault.

Why does it only trip when it rains?

Almost always water reaching an outdoor socket, light or a damaged cable. It needs tracing and sealing properly.

Could it be the fuse box itself?

Occasionally an old board or a worn RCD is the problem rather than the circuit. An electrician can test the device to be sure.

Still tripping?

If you have worked through the steps and it will not behave, do not spend another evening in the dark. Call 020 3653 2600 or see our fault finding and repairs service and we will get to the bottom of it.