MT 1 - TC 37/SC 37B/MT 1

IEC 61643-331:2020 is available as IEC 61643-331:2020 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 61643-331:2020 is a test specification for metal oxide varistors (MOV), which are used for applications up to 1 000 V AC or 1 500 V DC in power lines, or telecommunication, or signalling circuits. They are designed to protect apparatus or personnel, or both, from high transient voltages. This document applies to MOVs having two electrodes and hybrid surge protection components. This document also does not apply to mountings and their effect on the MOV’s characteristics. Characteristics given apply solely to the MOV mounted only in the ways described for the tests. This third edition cancels and replaces the second edition published in 2017. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- a Varistor MCOV rating assurance test;
- an energy rating test (2ms);
- revised Dielectric strength and insulation resistance tests.

IEC 61643-312:2013 is applicable to gas discharge tubes (GDT) used for overvoltage protection in telecommunications, signalling and low-voltage power distribution networks with nominal system voltages up to 1 000 V (r.m.s.) a.c. and 1 500 V d.c. They are defined as a gap, or several gaps with two or three metal electrodes hermetically sealed so that gas mixture and pressure are under control. They are designed to protect apparatus or personnel, or both, from high transient voltages. This standard provides information about the characteristics and circuit applications of GDTs having two or three electrodes. 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. Keywords: gas discharge tubes (GDT), overvoltage protection in telecommunications, signalling and low-voltage power distribution networks, nominal system voltages up to 1 000 V (r.m.s.) a.c. and 1 500 V d.c. The contents of the corrigendum of July 2013 have been included in this copy.

IEC 61643-311:2013 is applicable to gas discharge tubes (GDT) used for overvoltage protection in telecommunications, signalling and low-voltage power distribution networks with nominal system voltages up to 1 000 V (r.m.s.) a.c. and 1 500 V d.c..They are defined as a gap, or several gaps with two or three metal electrodes hermetically sealed so that gas mixture and pressure are under control. They are designed to protect apparatus or personnel, or both, from high transient voltages. This standard contains a series of test criteria, test methods and test circuits for determining the electrical characteristics of GDTs having two or three electrodes. 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. This second edition of IEC 61643-311 cancels and replaces the first edition published in 2001. It constitutes a technical revision. Specific changes with respect to the previous edition are: Addition of performance values. Key words: gas discharge tubes (GDT), overvoltage protection in telecommunications, signalling and low-voltage power distribution networks, nominal system voltages up to 1 000 V (r.m.s.) a.c. and 1 500 V d.c.