[A2_start]This part of IEC 61466 is applicable to composite string insulator units with a specified mechanical load (SML) of 40 kN to 600 kN for AC overhead lines with a nominal voltage greater than 1 000 V and a frequency not greater than 100 Hz.[A2_end]

[A1_start]It also applies to insulators of similar design used in substations or for railway applications[A1_end].

[A1_start]This standard applies to string insulator units of composite type with fittingsin accordance with IEC 61466‑1.[A1_end]

[A2_start]This standard specifies values for electrical and dimensional characteristics for composite insulators for overhead lines with a minimum lightning impulse withstand voltage (BIL) up to 3 100 kV and a specified mechanical load (SML) of 40 kN to 600 kN.[A2_end]