RVD or RCD, which one do I need?

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