WG 1 - TC 37/SC 37B/WG 1

IEC 61643-332:2024 describes the theory of operation, principles for the selection and application of MOVs to be connected to power lines or telecommunication or signalling circuits, up to 1 000 V AC or 1 500 V DC. These SPCs are designed to protect apparatus or personnel, or both, from high transient voltages. This document applies to MOVs having two electrodes and voltage dependents elements with or without disconnectors. It does not apply to assemblies that include MOVs and their influence on the MOV's characteristics. This standard specifically discusses the zinc-oxide type of MOVs.

Details the test specifications for metal oxide varistors (MOV), which are used for applications up to 1000 V a.c. or 1500 V d.c. in power line, or telecommunication, or signalling circuits. The MOVs are designed to protect apparatus or personnel, or both from high transient voltages. Does not deal with hybrid devices. Does not apply also to mountings and their effect on the MOVs characteristics.

Gas discharge tubes (GDTs) are used for applications up to 1 000 V a.c. or 1 500 V d.c. in communication or signalling circuits. They are defined as a gap, or series of gaps, in an enclosed discharge medium other than air. They are designed to protect apparatus or personnel, or both, from high transient voltages. This standard does not specify requirements applicable to complete surge protective devices, nor does it specify total requirements for GDTs employed within electronic devices, where precise coordination between GDT performance and surge protective device withstand capability is highly critical.