An RCD, or residual current device, is one of the most important safety features in your home. It constantly monitors the flow of electricity and cuts the power in a fraction of a second if it detects a fault. Without it, a faulty appliance or damaged cable could be fatal.
What does an RCD look like?
Most modern consumer units (fuse boards) have RCDs built in. They look like standard circuit breakers but have a small test button on the front, usually marked with a T. If your fuse board still uses rewirable fuses or old-style MCBs without RCD protection, it is worth getting it upgraded.
How to test it
Testing your RCD takes about ten seconds. Press the test button. The RCD should trip immediately and cut power to the circuits it protects. Flip it back on and everything should come back to life. If it does not trip, or if it does not reset, call an electrician.
How often?
We recommend testing your RCDs every three months. It is quick, it is free, and it could save your life. Set a reminder on your phone if it helps. Many people test theirs when the clocks change, twice a year at minimum.
When to call a professional
If your RCD keeps tripping without you pressing the test button, there is a fault somewhere in the circuit. Do not just keep resetting it. Call a qualified electrician to investigate. Repeated tripping is your RCD doing its job and warning you of a problem.
