Consumer Unit Keeps Tripping: What to Check and When to Call
Why a consumer unit or RCD keeps tripping, safe checks you can make by unplugging appliances, how to reset it and when to call a registered electrician.
A consumer unit that trips is doing its job: cutting the supply when something is wrong. The trouble is working out what that something is. Sometimes it is a faulty kettle, and sometimes it is a fault in the wiring. This guide covers sensible checks that do not involve touching fixed wiring, and the signs that mean it is time to call a professional.
Understand what tripped
Look at the consumer unit. Most modern ones have a row of switches.
- The main switch controls the whole supply.
- RCD or RCBO switches protect against current leaking to earth, and trip very fast.
- MCBs (miniature circuit breakers) protect individual circuits against overload and short circuits.
Note which switch has dropped. If a single circuit trips, the problem is likely on that circuit. If the RCD trips, think earth leakage, often from an appliance, damp or damaged cable.
Safe checks you can make
- Unplug everything on the affected circuit, or in the whole house if the RCD tripped.
- Reset the switch. If it stays on, plug appliances back in one at a time, switching on after each.
- Watch for the appliance that causes the trip. If it trips as soon as one item is plugged in, that appliance is probably faulty. Leave it unplugged and do not use it.
- Check for damp or water. Outside sockets, bathrooms, kitchens and garden equipment are common culprits.
- Think about timing. Does it trip in wet weather, when the oven is on or at the same time each day?
Never poke around inside the consumer unit or remove its cover.
Common causes
- A faulty kettle, heater, washing machine or other appliance.
- Overloading a circuit with too many heating or cooking appliances.
- Damp getting into outdoor sockets or light fittings.
- Damaged or chewed cable.
- Ageing sockets or switches that have loose or burnt connections.
- Old wiring with deteriorating insulation.
- A failing RCD or breaker.
When it keeps tripping with nothing plugged in
If a circuit trips immediately with everything unplugged, or the RCD trips repeatedly and you cannot find an appliance responsible, stop resetting it again and again. Repeated resetting can mask a serious fault. Leave that circuit off if the rest of the house is safe, and call a registered electrician.
Call an electrician urgently if
- You smell burning or see scorch marks.
- The consumer unit or a socket is hot, crackling or buzzing.
- A breaker will not reset and the cause is unclear.
- Water has got into electrical fittings.
- You received an electric shock or tingle from an appliance.
In an emergency, switch off at the main switch if it is safe, keep people away and call 999 if there is fire or injury. For call-out expectations, see electrician call-out charge.
Preventing repeat trips
- Spread heavy appliances across different circuits.
- Do not overload extension leads. Extension leads and overloaded sockets explains the limits.
- Replace old, frayed or damaged leads and appliances.
- Keep outdoor sockets and equipment dry.
- Have the installation inspected if it is old. An EICR will show whether the wiring is sound.
A worked example
The RCD trips every evening at around 7pm. Unplugging the kitchen appliances one by one shows nothing changes, but the household remembers the outdoor lights come on at dusk. In wet weather the trip happens earlier. Switching off the outdoor light switch stops the trips, which points to damp in the outdoor light fitting. The householder leaves the light off and calls an electrician to check it. Writing down the time and conditions was what pointed to the cause. This is an illustrative story rather than a diagnosis, because every home differs.
A simple fault diary
Keep a note for a week:
| What to record | Why it helps |
|---|---|
| Date and time of each trip | Reveals patterns, such as dusk or morning |
| Which switch tripped | Narrows it to a circuit or the RCD |
| What was on at the time | Points toward an appliance |
| Weather | Suggests damp ingress |
Take a photo of the consumer unit showing which switches are down, and share that with the electrician.
Common mistakes
- Holding the switch up while resetting, which can mask a fault.
- Taping or wedging a breaker in the on position.
- Moving an appliance to another circuit and assuming the problem is solved.
- Opening the consumer unit cover to look inside.
- Ignoring a tripping freezer circuit, which risks food spoilage.
Edge cases
- Rented homes: report repeated tripping to your landlord or agent in writing.
- Flats: a fault outside your flat may not be yours, but a trip that affects only your consumer unit is for your electrician or landlord to investigate.
- Older homes with no RCD: an upgrade is worth discussing with an electrician.
When to call a professional
Once an obvious appliance has been ruled out, fixed wiring and the consumer unit are for a registered electrician. If something is hot, smells of burning or has scorch marks, leave the circuit switched off.
Frequently asked questions
Is it safe to keep resetting a tripping breaker?
Once or twice after unplugging suspect items is reasonable. Repeatedly forcing it back on can hide a dangerous fault, so get it investigated.
Can an old consumer unit cause nuisance tripping?
Yes, particularly where it is combined with old wiring. An electrician can test the circuits and the protective devices to find out.
Why does my RCD trip when it rains?
Damp in outdoor sockets, lights or garden equipment is a common cause. Dry the equipment and have fittings checked if it recurs.
Can I leave my freezer on a tripping circuit?
It is safer not to rely on it. Move the freezer to a working circuit if you can do so safely using a short, undamaged lead, and have the fault investigated promptly.