- Type A RCDs detect and provide protection for both AC and pulsating DC currents – giving better protection with modern appliances, LEDs, batteries, and solar arrays.
- In April 2023, Western Power stipulated that Type A RCDs must be installed rather than Type AC RCDs – learn why below.
There are many different types of RCDs, each with their own pros and cons.
The Type AC RCD was commonly used in Western Australia until 2023. This RCD detects and provides protection for AC (sinusoidal) currents, which is the type of current that comes in from the public power grid.
The April 2023 “Wiring Rules” update
However, as of April 2023, Western Power released an update in line with a new Australian Standard that says: “As stipulated in AS/NZS 3000:2018 Wiring Rules clause 2.6.2.2.2, Type AC RCDs must not be installed in Australia from 30 April 2023.”
This means Type AC RCDs are no longer used by licensed electricians for RCD safety switch installations; Type A RCDs are used instead.
What benefit is there in introducing this Australian Standard and changing compliance laws? Why are Type A RCDs better? To find out why, we need to first understand what a Type A RCD is:
What are Type A RCDs?
Type A RCDs are designed to work on both sinusoidal alternating currents (the current that comes from the main power grid) and residual pulsating direct currents (DC), making them superior to Type AC RCDs.
On the other hand, Type AC RCDs are designed to only detect residual alternating currents (sinusoidal).
The following symbols can be found on RCDs to help identify which type they are:
Why is detecting pulsating DC important?
Nowadays, our electricity circuits are more complicated – for example, we’ve gone from traditional globes to LED lighting, and a simple connection from the grid to integrated solar and battery power systems. Our electricity is no longer simply always using AC!
For example, on the supply side, solar panels and batteries use direct current (after all, the sun’s energy is constantly beaming, not pulsating). This direct current needs to be converted to AC and synchronised with the main power for it to become standardised and useful throughout the home.
On the demand side, many modern appliances can use different voltages and may convert AC into DC (such as your phone charger that converts AC into DC for your battery).
Also, diodes (LED stands for ‘light emitting diode’) only allow electricity to pass in one direction (like a boom gate at a car park entry). So, whenever an alternating current hits a diode, the bottom half of the wave is blocked (back in the image, you’ll notice the flat line between waves for the Type A RCD rather than it flowing into a bottom half of the wave).
When everything is working as it should, this is fine – AC runs through the house and any different current type or voltage feeding in is synchronised, and any different current or voltage going out is converted to such accordingly – but what about when there’s a fault?
The older, Type AC RCDs can’t detect DC faults, but electrical appliances and equipment such as the following can cause DC electrical faults:
- Battery storage
- Dishwashers
- Electric Vehicle charging stations
- Inverters (such as solar power inverters)
- LED lighting
- Washing machines and dryers
Why are Type A RCDs better?
Type A RCDs not only detect faults in alternating currents but can also detect pulsating DC residual faults. So, Type A RCDs are better for our modern homes and businesses, providing a more comprehensive protection.
Type A RCDs can safely be used in electrical circuits that contain both AC and DC operated equipment.
How does this affect me?
In Australia, existing switchboards containing Type AC RCDs don’t need to be replaced unless electrical work connected these switchboards is conducted.
This includes, but is not limited to the following:
- All new electrical work.
- Alterations to existing installations involving new circuits installed.
- Switchboard upgrades.
- Replacement of faulty RCD units.
- Builder’s power pole supplies (as they’re regarded as an electrical installation).
Keeping your family protected!
Why is this change necessary? Because modern electrical equipment increasingly uses DC current, or can create DC electrical faults.
Safety standards need to keep up as our lives change with new technology. In Australia, any upgrades or new electrical installations will now use Type A RCDs to better protect your electrical appliances, and most importantly, to protect you and your family!
If you live in Perth or the Peel and need safe electrical work done, call Sarros Electrical – Perth’s reliable electricians!
