scope:

This standard is applicable to string insulator units of the cap and pin type with insulating parts of ceramic material or glass, intended for a.c. overhead lines with a nominal voltage greater than 1000 V and a fequency not greater than 100 Hz. It also applies to insulators of similar design used in sub-stations. This standard applies to string insulator units of the cap and pin type either with ball and socket couplings or with clevis and tongue couplings. The object of this standard is to prescribe specified values for the mechanical characteristics and for the main dimensions of string insulator units of the cap and pin type.