IEC 61156-1-4:2018 specifies a method to assess the thermal behaviour of cables arranged in bundles, for digital communications. A method is described to determine the temperature increase in cable bundles for certain remote powering currents as a basis to analyse the expected performance under several test arrangements described in standards dealing with the installation of cabling systems.
It is only intended to provide guidance to assess the thermal behaviour of cables for digital communications in reference environmental conditions and arrangements. It is therefore not intended to become a type of test method.
This first edition cancels and replaces IEC PAS 61156-1-4, published in 2010. This edition includes the following significant technical changes with respect to the previous edition:
a)   Several test arrangements are considered;
b)   The mathematical approach was revised.