What Changed in the Wiring Rules
From 1 May 2023, electricians can no longer install Type AC RCDs for most new or upgraded electrical work.
The standard now requires Type A RCDs or Type A RCBOs for all new final sub-circuits, especially where battery storage or solar equipment is installed.
This rule is set out in Clause 2.6.2.2.2 of Amendment 2, AS/NZS 3000:2018.
Why Type A RCDs and RCBOs Are Critical
Modern electrical equipment such as inverters, batteries and EV chargers can produce pulsating DC leakage currents.
Older Type AC RCDs only detect standard AC earth faults. They will not trip if there is a DC leakage fault.
Type A RCDs and RCBOs detect both AC and pulsating DC leakage, which makes them suitable for modern systems.
For blackout or battery backup setups, every circuit supplied by the backup system must be protected by a Type A device.
What This Means for Existing Installations
If your switchboard still has Type AC RCDs, you do not have to replace them unless you are altering, extending or upgrading those circuits.
When you install a battery backup or modify circuits, the updated standard requires the use of Type A RCDs or RCBOs.
In practice this means that if your installer finds AC-type RCDs on circuits feeding the backup supply, they will need to be replaced before the battery can be connected.
Risks of Not Upgrading Before Battery Installation
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The new battery or blackout protection system will not be compliant and may be refused connection
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Faults caused by DC leakage may not be detected, increasing the risk of electric shock or fire
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Safety inspections or insurance assessments may fail due to non-compliance
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You may lose eligibility for rebates that require compliant protection devices
Practical Steps for Homeowners
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Check your switchboard. Look at the label on your RCDs or RCBOs. If you see “Type AC,” those devices cannot be used for new or altered circuits.
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Arrange an inspection. A licensed electrician can confirm the type of devices you have and identify any circuits that need upgrading.
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Plan the upgrade. If you are adding a battery, make sure every circuit that will run from the backup supply is protected by a Type A RCD or RCBO.
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Upgrade only where required. You do not need to replace older RCDs that remain untouched and are not part of the backup system.
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Keep records. Keep invoices and test results from the electrician as proof of compliance.
Frequently Asked Questions
Do I need to replace every RCD in my home now?
No. Only circuits that are being altered or will run from the battery backup supply need to be upgraded to Type A RCDs or RCBOs.
What is the difference between an RCD and an RCBO?
An RCBO combines the protection of an RCD with a circuit breaker in one unit. In most battery installations, electricians prefer Type A RCBOs because they provide both residual current and overcurrent protection in a single device.
When do these rules apply to me?
The rules apply whenever you install or upgrade equipment such as solar with battery backup, backup circuits for blackout protection, or any new subcircuits for modern appliances.
Can any electrician handle the upgrade?
Yes. Any licensed electrician familiar with Amendment 2, AS/NZS 3000:2018 can supply and install compliant Type A RCDs or RCBOs.