This part of IEC 61 466 is applicable to composite string insulator units for a.c. overhead lines with a nominal voltage greater than 1 000 V and a frequency not greater than 1 00 Hz.
It also applies to insulators of similar design used in substations or on electric traction lines.
This standard applies to string insulator units of composite type with ball, socket, tongue, clevis, Y-clevis or eye couplings, or a combination thereof.
