What is an RCD and How Does it Work?
RCDs, or residual current devices
A residual current device (RCD) is one of the best ways to protect yourself from electrical equipment. Accidents, after all, can happen. And the dangers of electricity mean that the consequences of these accidents can be severe and even fatal. By installing RCDs into your electrical systems you can significantly reduce the risk of electric shock.
Understanding what an RCD is and how it works could make a real difference to the safety of your electrical equipment, so let’s take a closer look at RCDs.
How Do RCDs Work?
An RCD is a safety device which is able to detect faults in electrical supplies and immediately switch the circuit off. This prevents the flow of electricity and provides protection against electric shocks. For example, a sudden surge of electricity will cause the RCD to trip out and shut down the current. As mentioned earlier, this reduces the risk of electric shock, but it also prevents the risk of electrical fires developing from faulty equipment.
Types of RCD
There are more than one type of RCD and the most common ones you will encounter are:
- Fixed : Typically found within a fuse box, a fixed RCD delivers the best protection against electric shocks. A fixed RCD is capable or protecting individual circuits and more complex setups which are comprised of multiple circuits. This type of RCD is, given its fixed position, constantly providing protection to your circuits.
- Portable : As the name suggests, a portable RCD can be moved to wherever it’s required. A portable RCD is most commonly used when your options are limited for installing an RCD such as on a construction site. The portable RCD simply plugs into an available socket outlet and is then ready to have an electrical device plugged into it.
- Socket Outlet RCD: Replacing a standard socket outlet, a socket outlet RCD provides a much safer option for working with electrical devices. They are commonly found in extension cables and used for outdoor appliances such as lawnmowers.
What would trip an RCD?
An RCD is considered a highly reliable device and will prevent electrical shocks in around 97% of all cases. Naturally, this is a success rate which is highly favourable to your well-being, but it is not a 100% guarantee. Therefore, you should always be careful when working with electrical applications and RCDs by following these best practices:
- Test Your RCDs
All RCDs will have a test button built into them so that you can test that they are working and will disconnect the circuit. You should run a test on each RCD every three months to confirm that they are in good working order. If the test button does not activate the trip then contact an electrician to investigate this further.
- Check Your Wiring
It’s important that any electrical installations (and the RCDs themselves) are checked every 10 years. Wiring can deteriorate over time and circuits can easily malfunction, so it’s crucial that you cover every base rather than relying on the promise of an RCD alone.