scope:

This standard applies to post insulators and post insulator units of ceramic material or glass intended for indoor or outdoor service, and to post insulators of organic material intended for indoor service in electrical installations or equipment operating on alternating current systems with a nominal voltage greater than 1000 V and a frequency not greater than 100 Hz. It may also be regarded as a provisional standard for insulators for use on direct current systems. The insulators covered by this standard are primarily intended for use in isolators (disconnectors) or as bus-bar or fuse supports. This standard is intended to establish standard values of those electrical characteristics, mechanical characteristics and dimensions which are essential for the interchangeability of post insulators and post insulator units of the same type.