IEC Technical Report 61439-0

IEC TR 61439-0:2022 standards for low-voltage switchgear and controlgear assemblies, there are system and application details that are specified by the specifier to enable the manufacturer to produce an assembly that meets the needs and expectations of the specifier.
IEC/TR 61439-0:2022, identifies from the specifier’s perspective those functions and characteristics that are defined when specifying assemblies. It provides:

an explanation of the assembly characteristics and options within the IEC 61439 series;
a guidance on how to select the appropriate options and define characteristics so as to meet specific application needs; and
an assistance in the specification of assemblies.

References within this document to the interface characteristics of an assembly and the requirements with which they will comply assume that the assembly is designed, manufactured, and verified in accordance with the relevant part of the IEC 61439 series.
This third edition cancels and replaces the second edition published in 2013. It constitutes a technical revision.
This third edition includes the following significant technical changes with respect to the previous edition:

alignment with IEC 61439-1:2020;
addition of new content in Clause 13 regarding current ratings;
addition of a new subclause 12.8.1 detailing the fundamentals of the forms of internal separation;
alignment of Annex B with Annex AA of 61439-2:2020;
removal of the annexes detailing items subject to agreement between specifier and manufacturer for all product parts as not all of them can always be up to date