A tripping fuse box is your electrics doing their job — cutting power to protect you from something that’s gone wrong. The trick is working out *what*. This guide walks through the common causes, a safe step-by-step way to narrow it down yourself, and when it’s time to call an electrician.

First, what’s actually tripping?

Modern boards have two kinds of protective device:

• MCB (circuit breaker) — trips on overload or a short circuit (too much current).
• RCD — trips on earth leakage (current escaping to earth, e.g. through a faulty appliance or water). An RCD often protects several circuits, so when it goes, multiple things switch off at once.

Knowing which one tripped tells you a lot: a single MCB points to one circuit; the RCD taking out half the house points to an earth-leakage fault somewhere in that group.

The common causes

1. An overloaded circuit. Too many high-power appliances on one circuit — heaters, kettle, microwave together. The MCB trips to prevent overheating.

2. A faulty appliance. The most common cause of RCD tripping. A failing kettle, washing machine, toaster, or even a phone charger can leak current to earth and trip the RCD.

3. Water where it shouldn’t be. A leak reaching a socket, light fitting, or the consumer unit causes earth leakage — common after a roof or plumbing leak.

4. A wiring fault. Damaged cable (a nail through a wall, rodent damage, perished old insulation) or a loose connection.

5. A faulty switch, socket, or light fitting. Especially outdoor sockets and garden lighting exposed to damp.

Find the cause safely — step by step

You can narrow down an RCD trip yourself without touching any wiring:

1. Unplug everything on the affected circuits.
2. Reset the tripped breaker/RCD.
3. If it stays on, plug appliances back in one at a time, waiting after each.
4. When it trips again, the last appliance you plugged in is the likely culprit — stop using it and get it checked or replaced.

If the board won’t reset even with everything unplugged, that points to a fault in the fixed wiring itself — stop there and call an electrician.

When to stop and call an electrician

Call a professional if:

• The board won’t reset with everything unplugged
• It trips repeatedly and you can’t find an appliance cause
• There’s a burning smell, scorching, or buzzing at the board — switch off and treat as urgent (see our emergency electrician service)
• The fault followed water ingress
• Your board is old with rewireable fuses or no RCD — a tripping problem is a good moment to assess it

“Nuisance tripping” and old boards

If a single faulty appliance keeps taking out half your house, that’s often a sign of an older shared-RCD board. Upgrading to a board with per-circuit RCBOs means a fault only trips the one affected circuit — far less disruptive and much easier to diagnose. Our RCD vs RCBO guide explains the difference, and our fuse box replacement guide covers upgrading.

Could it be the appliance or the wiring?

A rough rule: if unplugging a specific appliance stops the tripping, it’s the appliance. If the circuit trips with nothing plugged in, or trips at random with no pattern, it’s more likely the wiring or a fixed accessory — that needs an electrician with test equipment to trace.

Don’t just keep resetting it

It’s tempting to keep flicking the breaker back on. Don’t — repeated tripping means something is genuinely wrong, and overriding it removes your protection. If you can’t quickly find an appliance cause, get it diagnosed.

Get tripping sorted

If your fuse box keeps tripping and you can’t find why — or there’s any burning smell — GFL Electrical can trace the fault and fix it properly. We’re NICEIC-approved electricians covering East London. Call 020 3774 5604 or get in touch.