A residual current device, or RCD for short, is a life-saving device designed to protect you against fatal electric shocks if you touch something that is live, such as a bare wire. It can also provide some protection from electrical fires. RCDs provide a level of personal protection that you cannot receive from a regular fuse or circuit breaker.

What does RCD protection do?

As a sensitive safety device, an RCD will automatically switch off the electricity if there is a fault. IT is designed to protect against all risks of electrocution and fire caused by earth faults.

How does it work?

It will continuously keep an eye on the electric current flowing through one or more circuits that it must protect. If it detects electricity flowing somewhere it shouldn’t, such as a person touching a live wire, the RCD will switch off the circuit immediately. This will significantly reduce the risk of death or serious injury.

What are the main types of RCD?

RCDs are there to protect you from electric shock in potentially dangerous areas such as the bathroom or your garden. There are also numerous RCD types to keep you safe.

  • Fixes RCDS – installed in the consumer unit and protects individual or groups of circuits. This type offers the highest level of protection as it protects the wiring, sockets, and any connected appliances.
  • Socket RCDs – Special socket-outlets with an RCD built into them and can be used instead of a standard socket. This only protects the person in contact with equipment, including its lead.
  • Portable RCDs – These plug into any standard socket, which you can then plug an appliance into. They are useful when neither fixed nor socket RCDs are available. However, they only provide the same protection as a socket RCD.

Can you rely on RCDs?

RCDs are approximately 97 per cent reliable but testing them regularly will help keep them that way. If you have fixed RCD protection, you and your family will be in a much lesser risk of electric shock. It can also protect against the risk of fire caused by faulty wiring or appliances.

It is important to remember that although the risk is reduced, it doesn’t mean you can be careless. We highly recommend you test your electrics no fewer than once every ten years. This will ensure the safety of yourself and anyone else in your home. In the event of discovering a fault with your wiring or an appliance, stop using it immediately and get in touch with a registered electrician.

All fixed and socket RCDs must receive testing every three months. It is recommended that you test portable RCDs each time you use them. If you hold the test button for a long time and the RCD does not switch off the electricity supply, please see the advice of a registered electrician.

How much will RCD protection cost?

A plug-in RCD can cost as little as £10, but a fixed RCD will likely cost more. However, it will also provide your home with more protection, keeping your family safe.

How do I check whether I already have fixed RCD protection?

Looking at your consumer unit, check for a device with a pushbutton marked “T” for “test”. This button is part of an RCD. If an RCD is fitted, there should also be a label somewhere on or near the consumer unit that reads “test quarterly”.

Have your RCD installed correctly with expert help

At CEB, we are proud to offer a wide range of electrical services for both domestic and commercial environments. If you would like to learn more or would like a quote, get in touch.

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