When your RCD keeps tripping, start with this checklist

If your RCD or RCBO keeps tripping, it can be frustrating and worrying—especially when half the house suddenly loses power. Don’t panic. By staying calm and following a step-by-step approach, you can often identify the cause or at least narrow it down. This helps you decide whether it’s a simple issue you can manage safely or if it’s time to call a qualified electrician to diagnose and fix the problem properly. Remember, safety comes first when dealing with electrical faults.

What your RCD actually does

An RCD (residual current device) constantly compares the electricity going out on a circuit with the electricity coming back. If it detects a small difference, it assumes power is leaking to earth and cuts the supply in a fraction of a second.

That fast cut-off reduces the risk of electric shock and electrical fires. So when an RCD trips, treat it as a safety warning, not just an annoyance, and resist the urge to keep flipping it back on without thinking.

Safety-first actions to take straight away

Before you start any checks, put safety at the top of the list. Never remove consumer unit covers, never touch bare wires and never work on a circuit that might still be live.

If you smell burning, see scorch marks or hear crackling, switch the main switch off and call an electrician immediately. Do not attempt to reset anything until it has been checked.

• Reset calmly: Push the RCD switch fully down, then firmly back up once, not repeatedly.

• Stay dry: Do not touch the consumer unit with wet hands or standing on a wet floor.

• Use the test button: If power is on and safe, press the RCD test button occasionally to confirm it trips correctly.

Reading the pattern: what the tripping behaviour tells you

The way your RCD trips can give useful clues. Pay attention to when it happens, what is running at the time and whether it affects part or all of the property.

Trips instantly when you reset it

If the RCD trips the moment you try to reset it, even with everything seemingly off, that can indicate a more serious fault on one of the connected circuits or a failed appliance still plugged in.

Turn off all circuit breakers protected by that RCD, reset the RCD, then bring the breakers back on one by one. If it trips as soon as you turn on a specific breaker, you have narrowed the issue to that circuit and should call an electrician.

Trips after a few minutes of use

When the RCD stays on at first then trips after a few minutes, it can point to heat or moisture building up in a cable, accessory or appliance. Common culprits include immersion heaters, ovens and dishwashers.

Make a note of what was running each time it tripped. The more consistent the pattern, the easier it is for an electrician to track down the fault.

Trips when a certain appliance runs

If you notice that the RCD only trips when the kettle, dishwasher, washing machine or EV charger is on, unplug that appliance fully and try again. Do not just switch it off at the front; pull out the plug or use the isolator switch.

If the RCD now holds steady with that item disconnected, there is a strong chance the appliance itself is at fault. It should be checked or repaired before you use it again.

Trips only at night or in bad weather

Trips that happen at night can be linked to timed equipment like immersion heaters, storage heaters, outside lights or EV chargers coming on. It can also be when fridges and freezers cycle more often.

If tripping seems worse during or after rain, think about any garden sockets, outdoor lights, pond pumps or external buildings. Moisture getting into outside wiring is a frequent cause of RCD operation.

Step-by-step isolation checks at the consumer unit

You can carry out basic, non-intrusive isolation checks at the consumer unit without taking covers off. These steps help you gather information without doing any DIY electrical work.

First, switch off and unplug as many appliances as you reasonably can, especially portable ones like kettles, toasters and phone chargers. Then go to the consumer unit.

Next, switch all circuit breakers protected by the tripping RCD to the off position. Reset the RCD, then turn the breakers back on one at a time, waiting a short while between each.

When the RCD trips as you turn on a particular circuit, make a note of its label, such as "sockets up", "kitchen" or "shower". Do not attempt to investigate further yourself; this is the point to call an electrician with that information.

Typical appliance suspects vs fixed wiring issues

Some appliances are more likely than others to cause earth leakage. In the kitchen, kettles, dishwashers, washing machines and tumble dryers are common candidates, especially if they are older or have had leaks.

Elsewhere in the home, immersion heaters, electric showers, storage heaters, EV chargers and hot tubs can all cause RCD tripping if they develop a fault or moisture ingress.

Fixed wiring problems are more often linked to outdoor lighting, garden sockets, pond pumps, old bathroom circuits and any DIY additions. Damage from gardening tools, water getting into joints, or rodents chewing cables can all show up as RCD trips.

• Unplug or isolate suspect appliances one at a time and test.

• Do not open fused spurs, junction boxes or light fittings.

• If unplugging does not help, treat it as a wiring issue and call an electrician.

Nuisance trips compared with genuine faults

Not every trip means something is about to fail catastrophically. Modern appliances can create small, normal leakage currents, and if several share the same RCD it can occasionally trip even though each item is working correctly.

These so-called nuisance trips might happen once in a long while, often when lots of equipment is running together. However, regular or repeat tripping, especially linked to one circuit or appliance, should always be treated as a genuine fault until proved otherwise.

If your RCD is very old or of a basic type, it might also be more prone to tripping than newer models. An electrician can test whether it is operating within the right limits or needs upgrading.

How an electrician tests an RCD fault

A qualified electrician will use calibrated test equipment to go far beyond visual checks. One key test is insulation resistance, which measures how effectively cables and appliances keep electricity where it should be, rather than leaking to earth.

They will also check RCD trip times and sensitivity, simulating different fault conditions to ensure it trips quickly enough but not too easily. By testing each circuit in turn, they can usually pinpoint whether the issue lies with the RCD itself, the wiring, or something plugged in.

Older homes in Bromley, Orpington and nearby areas

In places like Bromley, Orpington, Chislehurst, Sevenoaks, Tunbridge Wells and Maidstone, many homes have grown gradually, with extensions, loft conversions and garden offices added over several decades.

This can leave you with a consumer unit that has mixed-age wiring and labels that do not quite match what the switches actually control. Correct circuit identification is crucial for safe fault finding and makes RCD issues much easier to resolve.

A professional electrician can trace and label circuits accurately, check that outdoor and bathroom wiring meets current standards, and advise whether an upgrade would improve both safety and reliability.

Time to call in a professional

If your RCD keeps tripping, you have followed the checklist above and it still will not stay on, or you are at all unsure, it is time to bring in an expert. Do not ignore repeated trips or try to bypass the RCD, as that removes an essential layer of protection.

For friendly, experienced fault-finding and RCD testing in Bromley, Tunbridge Wells, Chislehurst, Maidstone, Orpington and Sevenoaks, contact LOOKS LOVELY LIMITED. Call 07939581540 to book a visit or arrange a safety check, or see our full range of electrical services on our electrical services page.