IEC 60947-4-1:2009 applies to the types of equipment whose main contacts are intended to be connected to circuits the rated voltage of which does not exceed 1 000 V a.c. or 1 500 V d.c. Starters and/or contactors dealt with in this standard are not normally designed to interrupt short-circuit currents. Therefore, suitable short-circuit protection forms part of the installation but not necessarily of the contactor or the starter. This third edition replaces the second edition published in 2000 and its Amendments 1 (2002) and 2 (2005). It is a technical revision. This edition includes the following significant technical changes with respect to the previous edition (2000) and its Amendments 1 (2002) and 2 (2005): - deletion of the test at -5 °C and +20 °C for thermal overload relays that are not compensated for ambient air temperature; - addition of conditions of the tests according to Annex Q of IEC 60947-1; - EMC tests: clarification of acceptance criteria and alignment with IEC 60947-1 for fast transient severity level; - Annex B, test for Icd: modification of the duration of the dielectric test voltage from 5 s to 60 s; - Annex B, electrical durability: improvement of the statistical aspects; - Annex H: clarification and introduction of new extended functions within electronic overload relays; - Annex K, procedure to determine data for electromechanical contactors used in functional safety applications: creation of this new annex. This standard shall be read in conjunction with IEC 60947-1, Low voltage switchgear and controlgear - Part 1: General rules. The provisions of the general rules are applicable to this standard, where specifically called for. This publication shall be read in conjunction with IEC 60947-1 :2007.