An RCD that trips once is doing its job. One that keeps tripping is telling you something’s wrong. The most common causes are a faulty appliance, moisture getting into an outside socket or light, damaged wiring, or too many appliances on one RCD adding up to small leaks of current. You can often find a faulty appliance yourself with a simple unplugging test. If that doesn’t find it, you’ll need an electrician. Our electrical team covers fault finding across Bracknell and the surrounding area.
What an RCD does
An RCD (residual current device) is a safety switch in your consumer unit. It constantly checks that the current going out on a circuit matches the current coming back. If some is leaking, for example through a faulty appliance or through a person, it cuts the power in a fraction of a second.
It’s one of the most important safety devices in your home. Never tape it up, bypass it or keep forcing it back on.
Common reasons an RCD keeps tripping
- A faulty appliance. Kettles, washing machines, dishwashers, tumble dryers, immersion heaters and outdoor equipment are frequent culprits.
- Moisture. Water in an outside socket, garden light, shed supply or bathroom fitting, often after heavy rain.
- Damaged cables. A nail or screw through a cable, rodent damage, or wear in older wiring.
- Several small leaks adding up. On older boards where one RCD protects many circuits, lots of appliances each leaking a tiny amount can be enough to trip it.
- A faulty RCD. Less common, but RCDs can wear out.
Safe checks you can do yourself
You can do these without taking any covers off:
- Switch off and unplug everything on the circuits that have tripped.
- Reset the RCD. If it stays on, the fault is probably in something you’ve unplugged.
- Plug appliances back in one at a time, switching each on. When the RCD trips again, you’ve likely found the faulty appliance.
- Check for water around outside sockets, lights and sheds after rain.
- If the RCD trips straight away with everything unplugged, the fault is in the fixed wiring. Leave it off and call an electrician.
Never open the consumer unit, sockets or light fittings to investigate. If you smell burning, see scorch marks or feel heat at a socket or the consumer unit, turn off the power at the main switch if it’s safe and get an electrician out.
When to call an electrician
Call an electrician if:
- The RCD trips with everything unplugged
- It trips at random with no obvious pattern
- It won’t reset at all
- You’ve found signs of burning, heat or damage
- You have an older fuse board with limited or no RCD protection
An electrician can carry out insulation resistance tests on each circuit to find exactly where the leak is. That’s much quicker and safer than trial and error.
Could your fuse board be the problem?
Older consumer units sometimes have one RCD protecting half the house, which makes nuisance tripping more likely and means one fault can knock out lots of circuits. Modern boards often use RCBOs, which give each circuit its own protection, so one fault only switches off that circuit.
If your board is old or tripping a lot, our guides on whether you need to upgrade your fuse board and consumer unit upgrades explain the options.
RCD tripping in Bracknell homes
Across Bracknell, Wokingham and Crowthorne, a lot of homes have had kitchens, extensions and garden rooms added over the years. Extra circuits on an older board, and outdoor supplies exposed to the weather, are two of the most common reasons we see RCDs tripping, especially after wet spells.
Frequently asked questions
Is it dangerous if my RCD keeps tripping?
The RCD itself is keeping you safe by cutting the power. The fault it’s detecting may be dangerous, though, so don’t ignore it or keep resetting it.
Why does my RCD trip when it rains?
Water is probably getting into an outside socket, light, cable or garden building supply. Leave that circuit off and get it checked.
Can I replace an RCD myself?
No. Work inside the consumer unit should only be done by a qualified electrician. It’s also notifiable work under Part P of the Building Regulations in England.
How often should I test my RCD?
Press the test button every few months. It should trip straight away. If it doesn’t, call an electrician.
RCD still tripping?
If you’ve tried the unplugging test and it’s still going, give us a ring on 01344 851023 or send us a message and one of our electricians will track the fault down.