13 September 2024
RVD or RCD, which one do I need?
Firstly let's explain what they do and why you need them.
An RCD or ‘Residual Current Device’ measures the outgoing and returning current and when there is any stray (going to earth, or in the case of a caravan to the chassis) it will turn the circuit off.
A RVD or ‘Residual Voltage Device’ measures the voltage on the earth (chassis of caravan) and when it rises over a certain set point turns the circuit off.
What do the rules require you to have?
AS3001 (Electrical installations—Transportable structures and vehicles including their site supplies) states
3.3.2 Protection against earth leakage current
(a) Sufficient residual current devices with a maximum rated residual current of 30 mA shall be located on or within the installation and connected in such a way that every final subcircuit of the electrical installation is protected against earth leakage current by one of these RCDs.
(b) These RCDs may be separate from or integral with the circuit-breakers required by Clause 3.3.1 but shall operate in all live (active and neutral) conductors of the circuit and shall be clearly identified in accordance with the requirements of Clause 3.3.1.4.
(c) In New Zealand, Type A RCDs shall be used.
Therefore to meet the requirements you must have an RCD protecting all circuits (Powerpoints/ACs etc) in the caravan and there is no mention of needing a RVD. A RVD is an extra safety device which shall be used in conjunction with an RCD (not as a replacement).
If your RCD does not operate as it should you should consult your installing electrician.
As always, If you have any questions reach out and ask away
Cheers,
Landon
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8 Comments
An RVD EMR will not work on its own and is combined with an RCBO and then will work on both mains and Isolated power AN RCD will also not work on its own and is combined with an ENB (Earth Neutral Bond) AND WILL ONLY WORD IN the mains (MEN) SYSTEM.
The statement of the RVD is not needed is misleading as it refers to AS/NZS3001 -2007 requirements and the new AS.NZS3001.2.2022 is supposedly stated not mandated and that is not correct there are 2 ways of approvals Legislative Reference Like as AS/NZS3000,ASNZS3001 is made mandatory by electrical Legislation in each state. and territory.
or Reference din AS/NZS 3000:Clause 7.8 of AS/NZS3000:2018covers "Specific Electrical Installations "and explicitly references AS/NZS3001.this means that any work falling under the scope or AS/NZS3001 must also comply with its requirements to satisfy the overarching legaly mandated AS/NZS3000 Standard and the RVD products are covered by 7.8.2.3Transportable structures and vehicles including their site supplies along with 7 .8.2.10 generating sets and 7/8/2/11 Inverters.
Due to the fact that all the statements technically refer to AS/NZS3001 -2007 a Standard superseded by AS/NZS3001/2/2022 that came into affect on 18Th November 2023 the statements are old hat and should be deleted.