04 Aug, 2022
Posted by Prime Time Electricians
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How Does An RCD Work In An Emergency?

Electrical safety is one of the most important aspects of home ownership. But this doesn’t just mean having the safety measures in place. It is one thing to have an RCD, circuit breaker or smoke alarm installed, but it is another to actually understand its purpose. It is vitally important that you know how safety measures work as this will also tell you what their limitations are. This will allow you to plan accordingly and be aware which aspects/areas of your home are less protected than others. 

This article will delve into RCDs. If you would like to read more about smoke alarms, check out our previous article here

How does an RCD work and how does it protect you in an emergency?

To start, what does RCD stand for? RCD stands for ‘Residual Current Device’. It is a safety device designed to protect you and the inhabitants of your home from a fatal electric shock. Some examples of common causes for RCDs include faulty appliances, careless DIY work or touching bare live wires. So what does an RCD do when it detects current flowing to somewhere it shouldn’t?

First and foremost, the RCD cuts the power supply to the circuit before the earth fault or other trigger causes the current to leak any further into something or someone it shouldn’t. This prevents an electric shock by stopping the current flow before it can flow through to the earth and complete the shorter path to the ground. The RCD will then keep the power off until someone manually switches the power back on. 

An RCD is also a good protection against electrical fires as it will cut the electrical current before it builds up the necessary heat to start a fire. 

How does an RCD work and how does it protect you in an emergency

Different types of RCDs

Fixed RCDs

Fixed RCDs are the most common type. These can be found inside the meter box of your home and one RCD of this type usually protects multiple wiring and outlets on a circuit. 

Socket-integrated RCDs

Socket-integrated RCDs are as the name suggests. This type of RCD is built into the wall-socket and only provides monitoring and protection for the devices plugged into it. Socket-integrated RCDs can be a good backup, providing a second layer of protection, and are useful to have in the interim if your fixed RCDs need replacing. 

Portable RCDs

Portable RCDs are also aptly-named. This type of RCD plugs into a wall socket and, similarly to the socket-integrated type, only monitor the devices plugged into them. They are most useful when travelling or working with power tools somewhere that might not have an RCD naturally installed (such as an older building, outdoor area or construction site). This type of RCD is also good for protecting outlets in the house if a fault is detected with the main fixed RCD and it needs to be replaced. 

RCDs vs circuit breakers

The operating process of an RCD may sound similar to that of circuit breakers, but there is a crucial difference. An RCD is designed to protect the occupants of your home from an electric shock, whereas circuit breakers are designed to protect the devices inside your home from overloading or short circuits. 

At the end of the day it is best to protect all aspects of your home. This will involve a combination of RCDs and circuit breakers. Having them working together will provide the most comprehensive circuit protection. 

What is RCD testing and why is it important?

Given their vital role in protecting the occupants of your home, it is important that your RCDs are tested regularly. This will ensure that any faults, malfunctions or age wear is detected before the device is required to act. Testing also covers whether the RCD is working at an acceptable speed, cutting the power to electrical circuits within a required timeframe. 

RCDs are tested by pressing the button marked ‘t’ or ‘test’. pressing this button simulates a fault, which should immediately prompt the RCD to cut the power supply to that circuit. If it does so, the RCD is working as intended. If the current remains flowing to the circuit after several seconds of pressing the test button, call a licensed electrician immediately and avoid using the devices on that circuit as much as you can. 

Time-wise, fixed RCDs and socket-integrated RCDs should be tested every three months, and a portable RCD should be tested every time you use it. 

Who should install, repair and test your RCDs?

Who should install repair and test your RCDs

As with most matters of electrical safety, RCD installation and testing is best done by a qualified residential electrician. They are far more knowledgeable and better equipped for testing, repairing or replacing RCDs if necessary. It is also important to remember that all houses rented or sold in Western Australia are required by law to have at least two RCDs installed. 

So if you need your RCDs tested, or perhaps you want some more installed, give Prime Time Electricians a call today on 1300 356 200.

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