MT 6 - TC 121/SC 121A/MT 6

IEC 60947-3:2020 applies to switches, disconnectors, switch-disconnectors and fuse-combination units and their dedicated accessories to be used in distribution circuits and motor circuits of which the rated voltage does not exceed 1 000 V AC or 1 500 V DC.
This fourth edition cancels and replaces the third edition published in 2008, Amendment 1:2012 and Amendment 2:2015. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
addition of critical load current tests for DC switches (see 9.3.9);
addition of requirements for a conditional short-circuit rating for disconnectors, switches, and switch-disconnectors protected by circuit-breakers (see 9.3.7.2);
addition of new categories for high-efficiency motors switching (see Annex A);
addition of new Annex E for connection to aluminium conductors;
addition of new Annex F for power losses measurement.  The contents of the corrigendum of October 2021 have been included in this copy.

IEC 62626-1:2014 applies to enclosed switches-disconnectors with rated voltages up to 1 000 V a.c. for repair and maintenance work or cleaning work in load circuits. Devices within the scope of this standard are derived from switch-disconnectors according to IEC 60947-3. Enclosed switch-disconnectors in this standard are suitable for isolation according to IEC 60947 series and are not supposed to be equipped with means for remote control or automatic switching to avoid unexpected or accidental start. These devices are not intended to be used for operational switching, quick start and stop or jogging.

The contents of the corrigendum of November 2013 have been included in this copy.