The surge protection device formerly known as MOV (Metal Oxide Varistor) has had a third iteration of amendments in standard AS/NZS 3100. The latest changes are at Draft postal ballot comment level (DR 17901 CP) and the version seems to make sense and give good direction to both designers and test labs. The proposal to ban Line to Earth Varistors has been addressed by allowing these devices provided a Gas Discharge Tube (GDT) of particular specifications is used in series with the component. The comments close on 14th July 2017. We expect to see this released as Amendment 1 to AS/NZS 3100:2017 later in the year. Once published, designers are encouraged to apply the new requirements for equipment fitted with Varistors.
Varistors (MOV’s) – New design rules
