IEC TS 60815-4:2016(E) which is a Technical Specification, is applicable as first approach for the determination of the required d.c. Unified Specific Creepage Distance for insulators with respect to pollution. To avoid excessive over or under design, existing operation experience should be compared and eventually additional appropriate tests may be performed by agreement between supplier and customer. It is applicable to:
- Glass and porcelain insulators,
- Composite and hybrid insulators with an HTM or non-HTM housing. This part of IEC 60815 gives specific guidelines and principles to arrive at an informed judgement on the probable behaviour of a given insulator in certain pollution environments.