How to reset a tripped RCD or circuit breaker
If part of your home has suddenly lost power, a switch in your consumer unit (fuse box) has probably tripped. Here's how to find it, find the faulty appliance and reset it safely.
- Time
- 15 minutes
- Difficulty
- Easy
- Steps
- 7
- Checked
What you’ll need
- Torch (a phone torch is fine) Search Amazon for LED torch
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Safety first
- Never try to hold a switch in the ON position or tape it up. It's tripping to protect you from shock or fire.
- If you smell burning, see scorch marks or the consumer unit feels hot, don't reset anything. Turn off the main switch if it's safe and call an electrician.
- Don't touch a consumer unit with wet hands, and never remove its cover. Work inside it must be done by a qualified electrician.
Step by step
-
Step 1: Check it isn't a power cut
If the whole street is dark, it's a power cut, not your electrics. Call 105, the free national power cut number, for updates. If only your home (or part of it) has lost power, carry on.
Next: step 2 -
Step 2: Find your consumer unit
It's usually under the stairs, in a hallway cupboard, the garage or near the front door. Inside you'll see a main switch, a row of circuit breakers (MCBs, one per circuit) and one or more RCDs, which have a test button marked T or Test.
Next: step 3 -
Step 3: Spot which switch has tripped
A tripped switch points down or sits in the middle, unlike the others. An RCD protects several circuits at once, so when it trips you lose power to several rooms. A single circuit breaker tripping usually affects just one circuit, such as the kitchen sockets or the upstairs lights.
Next: step 4 -
Step 4: Unplug and switch off appliances on that circuit
Something faulty usually causes the trip: a kettle, toaster, washing machine, outdoor light or anything that's got wet. Unplug everything on the affected circuits, and switch off appliances that are wired in.
Next: step 5 -
Step 5: Reset the switch
Push the tripped switch firmly back to ON (up). If it's a circuit breaker that's half-way, you may need to push it fully down first, then up.
Next: step 6 -
Step 6: Find the culprit
Plug appliances back in and switch them on one at a time, waiting a little between each. If the switch trips again when you turn one on, you've found the faulty appliance. Leave it unplugged and get it repaired or replaced.
Next: step 7 -
Step 7: Test your RCDs every so often
Pressing the RCD's test button should make it trip instantly. Push it back on afterwards. If it doesn't trip when you press Test, get an electrician to check it.
Tips
- Label each circuit breaker (kitchen sockets, upstairs lights and so on) so you can see straight away what has tripped.
- Keep a torch near the consumer unit.
- A circuit breaker can trip because of overload, such as a kettle, toaster and microwave on one circuit at once. That's different from a fault, but it's still worth spreading the load.
When to call a professional
Call a registered electrician (for example NICEIC or NAPIT registered) if the switch trips again with everything unplugged, it won't reset, it keeps tripping without an obvious cause, or the RCD doesn't trip when you press Test. These point to a fault in the wiring itself. Electrical Safety First suggests a periodic inspection of your home's wiring every 10 years for homeowners, and every 5 years for rented homes.
Questions people ask
What's the difference between an RCD and a circuit breaker?
A circuit breaker (MCB) switches off a circuit if too much current flows, for example from an overload or a short circuit. An RCD switches off if it detects electricity leaking to earth, for example through a person, which helps prevent fatal shocks.
Why does my RCD trip when it rains?
Water getting into outdoor sockets, lights or cables is a common cause. Get an electrician to check outdoor electrics.
Can I replace a fuse in the consumer unit myself?
Older boxes with rewirable fuses can be repaired with the correct rating of fuse wire, but it's safer to ask an electrician, who can also advise on upgrading to RCD protection.
Sources
Checked 9 October 2026. We wrote this guide in our own words, using:
- Electrical Safety First: fuse boxes explained (electricalsafetyfirst.org.uk)
- Electrical Safety First: RCDs explained (electricalsafetyfirst.org.uk)
- Electrical Safety First: your questions answered (electricalsafetyfirst.org.uk)
- Power Cut 105 (Energy Networks Association) (powercut105.com)
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Printed from howtoguides.uk/guides/how-to-reset-a-tripped-rcd/ · Checked 9 October 2026 · General information only. For gas, electrics, structural work, medical, legal or money decisions, use a qualified professional.