IEC TR 60664-2-1 ED3

Insulation coordination for equipment within low-voltage systems - Part 2-1: Application guide - Explanation of the application of the IEC 60664 series, dimensioning examples and dielectric testing

Scope

IEC TR 60664-2-1:2026 serves as an application guide, when using the IEC 60664 series for the design and verification of an insulation system of electrical equipment within low-voltage systems, in order to provide better understanding related to the:
- basic technical characteristics relevant for the design of clearances, creepage distances, and solid insulation,
- design for insulation coordination to clearances, creepage distances, and solid insulation and combinations of such,
- test and measurement of clearances, creepage distances, and solid insulation for electrical equipment and their components,
- practical examples for dimensioning of clearances, creepage distances and solid insulation.

This document is informative only and does not provide any additional requirements beyond the IEC 60664 series . It provides guidance to assist better understanding of the insulation coordination requirements and avoids repeating the content of the individual parts of IEC 60664 documents. In case of conflict between this document and documents mentioned above, requirements in these documents prevail over this technical report.

This document provides a summary for technical committees in the preparation of their standards, and for manufacturers of electrical equipment and components, on specific topics, activities and options which are considered when using the IEC 60664 series in their specific equipment or application. See Annex A.

This basic safety publication focusing on safety guidance related to IEC 60664 series is primarily intended for use by technical committees in the preparation of safety publications in accordance with the principles laid down in and .

One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications.

This edition includes the following significant technical changes with respect to the previous edition:
- the third edition of this technical report is reconstructed to align with the structure of 60664-1:2020 and 60664-1:2020/AMD1:2025;
- reference numbers indicated in this technical report are updated in line with the changes to clause and table numbers in 60664-1:2020 and 60664-1:2020/AMD1:2025;
- references to 60664-5:2007, withdrawn in 2014, are deleted, and replaced, where applicable, to reference to TR 63040 ;
- explanations of the principles of IEC 60664 series and examples of practical application are improved;
- Table A.1, Table A.2, and Table A.3 are combined into one table;
- Annex B, Annex C, and Annex D are deleted.