IEC 61439-1:2011 lays down the definitions and states the service conditions, construction requirements, technical characteristics and verification requirements for low-voltage switchgear and controlgear assemblies. This standard cannot be used alone to specify an ASSEMBLY or used for a purpose of determining conformity. ASSEMBLIES shall comply with the relevant part of the IEC 61439 series Parts 2 onwards. This standard applies to low-voltage switchgear and controlgear assemblies (ASSEMBLIES) only when required by the relevant ASSEMBLY standard as follows: - ASSEMBLIES for which the rated voltage does not exceed 1 000 V in case of a.c. or 1 500 V in case of d.c. - stationary or movable ASSEMBLIES with or without enclosure - ASSEMBLIES intended for use in connection with the generation, transmission, distribution and conversion of electric energy, and for the control of electric energy consuming equipment - ASSEMBLIES designed for use under special service conditions, for example in ships and in rail vehicles provided that the other relevant specific requirements are complied with - ASSEMBLIES designed for electrical equipment of machines provided that the other relevant specific requirements are complied with. This second edition cancels and replaces the first edition published in 2009. It constitutes a technical revision. This second edition includes the following significant technical changes with respect to the last edition of IEC 61439-1: - revision of service conditions in Clause 7 - numerous changes regarding verification methods in Clause 10 - modification of routine verification in respect of clearances and creepage distances (see 11.3) - adaption of the tables in Annex C and Annex D to the revised requirements and verification methods - revision of the EMC requirements in Annex J - shifting of tables from Annex H to new Annex N - new Annex O with guidance on temperature rise verification - new Annex P with a verification method for short-circuit withstand strength (integration of the content of IEC/ TR 61117) - update of normative references - general editorial review.