Midnight Trip? A Calm Homeowner's Guide to a Stubborn RCD

First, don't fight the switch

It is 2am, half the house has gone dark, and the consumer unit has clicked. An RCD or RCBO has tripped. That is not a sign the electrics are out to get you. It is usually a sign that something on a circuit is leaking current to earth, or that an appliance has developed a fault. The worst response is to reset it again and again until it stays up. The second worst is to tape it up, wedge it, or pretend it did not happen. Both turn a safety device into a problem waiting for a worse moment.

At Apex Sparks, we would rather you knew the sequence than panicked in the dark. Here is the calm version.

Know what has actually tripped

The consumer unit is the modern name for the fuse box. Inside it, an RCD protects a group of circuits, while an RCBO combines RCD and circuit-breaker protection for one circuit. If one side of the board is dead, an RCD may have tripped. If only the sockets or only the downstairs ring has gone off, it is more likely an RCBO. Some units show a small indicator; others simply have a switch sitting halfway or in the down position.

Do not remove the cover. Do not poke around inside. You only need to identify the switch and the circuits it controls.

The no-panic fault-finding flow

1. Pause and note what was running. Was the washing machine spinning, the tumble dryer on, the dishwasher heating, the kettle boiling, an EV charger active, or an electric shower in use? That detail is useful later.
2. Switch off and unplug portable appliances on the affected circuits. Do it calmly, using the plug, not by yanking the cable. If a plug feels hot, looks scorched, or smells of burning, stop and leave it alone.
3. Reset the device once. Push the switch firmly to the on position. One reset is diagnostic. Five resets is denial.
4. If it stays on, reintroduce appliances one at a time. Start with the item that was running when it tripped. Wait a few minutes between each. If the RCD trips when a particular appliance is plugged in, leave that appliance off and get it checked.
5. If it trips immediately with nothing plugged in, stop. That points to a wiring fault, moisture, or a hardwired appliance such as a cooker, immersion heater, or shower. This is electrician territory.
6. If it trips again after a successful reset, do not reset it again. Book a qualified electrician. Use torches, keep the fridge and freezer closed, and avoid running extension leads around the house as a workaround.

That is the whole flowchart in plain English: isolate, reset once, reintroduce, and stop if it repeats.

When one reset is enough

One reset is reasonable after you have switched off the obvious load. If the RCD holds and the house behaves, you have bought yourself time to investigate the appliance or book a visit. If it trips straight away, or trips again within minutes, the fault is still there. Resetting it repeatedly will not fix it and may mask a genuine danger.

There are times to skip the reset altogether. If you can smell burning, see scorch marks, notice water near sockets, or have a plug that is discoloured, leave the power off and call an electrician. If there is smoke or fire, get everyone out and call 999.

The usual suspects, without the guesswork

Common culprits include kettles that have boiled over, washing machines with leaking seals, dishwashers, tumble dryers, outdoor lights and garden sockets that have taken on water, and extension leads carrying too much. In 2026, more homes also have heat pumps, solar inverters, home batteries and EV chargers. These can add to earth leakage and make an existing issue show up as nuisance tripping. That does not mean the new kit is automatically to blame, but it does mean the whole installation needs to be in good order.

An RCD test button is there to check the device still operates. It is not a fault-finding tool. Press it quarterly, and if it fails to trip, that is its own fault and needs attention.

What not to do

Do not open the consumer unit. Do not replace a breaker with a bigger one. Do not remove an RCD because it keeps tripping. Do not run a faulty appliance through an extension lead to see if it behaves. Do not ignore a device that trips every time it is used. And do not let a quick internet fix talk you into work that belongs with a competent electrician.

When to call Apex Sparks

Call an electrician if the RCD will not reset, trips with nothing plugged in, trips on hardwired equipment, feels warm, buzzes, or if you have any doubt at all. A proper visit will include testing the circuit, checking for moisture and damaged accessories, and confirming the consumer unit is doing its job. That is not a failure on your part. It is how a safe home stays safe.