What to Do If Your RCD Keeps Tripping

Consumer unit with RCD switchInconvenience or Big Problem? Carry Out Some Basic Checks

A RCD that keeps tripping does so for a reason. Don’t ignore it, but follow some simple steps to get to the bottom of the fault.

We have all experienced the annoyance of the fuse box, or RCD as it is known in modern parlance, tripping out from time to time. Sometimes the cause is obvious – for example, the surge caused by a lightbulb blowing can be enough to do it, and all you need to do is replace the bulb, reset the RCD and all is well.

On other occasions, it can be a bit of a mystery. One thing is for sure, though – it is not doing it for fun, and you need to get to the bottom of what is behind it. Chelmsford electricians Bryden Electrical have helped put together the following check list that anyone can go through to find out what’s wrong.

What is an RCD

Before we start, it is worth having a clear idea of what the RCD is doing. Residual Current Devices are safety switches that cut the supply to an electrical circuit if they detect that it is unsafe. Many such problems only last for a fraction of a second – like the blowing bulb example – but understandably enough, your RCD will err on the side of caution and trip the circuit if there is the slightest risk.


If the problem is solved, for example you replace the bulb, you can reset the RCD and get on with your life. But if it trips again, you know there is a problem. The trick is finding it.

1) Everything off!

If nothing is switched on, there’s nothing to trip the circuit. Switch off all lights and sockets, not forgetting the cooker, heating and hot water systems that are likely to be on their own spurs. Now reset the RCD.

2) Look and listen

Before you start switching things on, take a slow walk round the house. Check for any sparks, fizzing noises or anything else out of the ordinary.

3) Switch on, gradually

Now you can start turning things on one at a time. With any luck, you will suddenly switch something on and the RCD will trip again. Congratulations, you have narrowed down the culprit, but you’ve not solved the problem yet.

4) Is it an appliance?

Suppose the RCD tripped when you switched the fridge back on. Unplug the fridge, and reset the RCD. If all is well, try plugging the switch into a different socket. If it trips again, you know that it is definitely the fridge that is causing the problem, and you can make a decision as to whether to get an electrician to give it a look over. If the fridge is old, you might just decide to replace it, but if it is still serviceable, it is worth getting it checked out, as it could be something as simple as a frayed wire that can be dealt with inexpensively.

5) Or is it the socket?

If all works fine with the fridge plugged in elsewhere, the problem is likely to be with the socket outlet itself. Now is the time to stop experimenting and to call in the experts – but at least you have power in the meantime, and only have one socket out of action!

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