IEC TS 60815-3:2025

IEC TS 60815-3:2025, which is a technical specification, is applicable for the selection of polymeric insulators for AC systems, and the determination of their relevant dimensions, to be used in high voltage systems with respect to pollution. The specification applies to insulators for outdoor installation only.
This document gives specific guidelines and principles to arrive at an informed judgement on the probable behaviour of a given insulator in certain pollution environment.
The contents of this document are based on CIGRE TB 158 and CIGRE TB 361, which form a useful complement to this document for those wishing to study in greater depth the performance of insulators under pollution.
This document does not deal with the effects of snow or ice on polluted insulators. Although this subject is dealt with by CIGRE TB 158, current knowledge is very limited and practice is too diverse.
The objective of this document is to give the user means to
- determine the reference unified specific creepage distance (RUSCD) from site pollution severity (SPS) value or class,
- choose appropriate profiles,
- apply correction factors for altitude, insulator shape, size and position, etc. to the RUSCD.
This second edition of IEC TS 60815-3, together with IEC TS 60815-1, cancels and replaces the first edition of IEC TS 60815-3:2008. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) Terms and definitions are modified or introduced in this document;
b) From RUSCD of reference insulator to USCD of candidate insulator, the correction factors are introduced and revised, such as altitude correction, diameter correction, shed profile correction and - parallel insulator number correction;
d) The general guidance on materials is revised. The concept of hydrophobicity transfer and hydrophobicity transfer material (HTM) are introduced, recognising that a reduced creepage distance may be used for HTM insulators.