Your questions about RCD changes answered
Image: IPD
The minimum standard of RCD used in final sub-circuit applications has changed.
With the final transitional arrangement of Amendment 2 of AS/NZS 3000 coming into effect on the 29 April 2023, you need to know what the new requirements are.
Here are the answers to some of the questions you asked about changes to RCD minimum standards.
Q: Is a Type B RCD needed to stop a VSD nuisance tripping or to give a broader range of protection? What type of safety switch is the best to prevent VSD nuisance tripping?
A: An RCD interprets the rapid switching from a VSD as a high frequency. That high frequency can be getting beyond the capabilities of the low-level RCDs. For that reason, Type B are recommended, to give the greater protection to nuisance tripping.
Q: Do you need to upgrade to a Type A from a Type AC when extending or increasing load on existing final sub circuits?
A: If it’s an existing circuit and you are adding a power point to the circuit for example, you would not need to change over the RCD type at that point.
Q: Can Type AC be used to replace an existing Type AC?
A: If you are replacing a Type AC that is damaged or nonfunctioning you can only replace it with a Type A.
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Q: Do we need to install an RCD for solar system?
A: AS/NZS 3000 does not require an RCD to be installed for a solar system as it is considered a generation circuit and not a final sub circuit. Should the manufacturer specifically say an RCD is to be installed, follow that instruction. The manufacturer’s instructions should specify the type of RCD to use.
Q: What is the approximate cost difference between a Type A and Type F?
The price depends on the size and number of circuits to be protected. For some ranges of RCD, the price difference between Type A and Type F can be about 10-20 per cent. For higher-end options a Type F can be twice as expensive as a Type A.
Q: Do Standards require Type B RCDs for EV Charger circuits?
A: While AS/NZS 3000 does not require a Type B to be installed on EV Charger circuits, the manufactures instruction need to be consulted to confirm if they require one to be installed for correct operation.
Q: What can be done with unused, old Type ACs?
A: You must make sure the wrong type of RCD is not used where it should not be. If you’ve got some Type ACs in stock, you should discuss with your wholesaler if they have a returns option, be careful you don’t use it in a new job.
Q: Are there any products that give similar protection for Phase to Phase, Phase to Neutral faults?
A: The Arc Fault Detection Device is available for this. The AFDD can detect a wave form which is the characteristic of an arc. Using AFDDs is currently optional, but that could change in coming years.
If you have any questions around RCDs or other technical questions make sure you ask the experts. Master Electricians have unlimited access to the MEA Technical Hotline as part of their membership. Phone 1300 889 198 today.