IEC 60305:1995 pdf download.Insulators for overhead lines with a nominal voltage above 1 000 V Ceramic or glass insulator units for ac. systems Characteristics of insulator units of the cap and pin type.
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IEC 60305 applies 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 1 000 V and a frequency not greater than 100 Hz. It also applies to insulators of similar design used in substations.
IEC 60305 applies to string insulator units of the cap and pin type either with baB and socket couplings or with clevis and tongue couplings.
IEC 60305 applies to string insulator units for use on overhead lines in clean areas and polluted areas. For use in areas characterized by very heavy pollution levels and for other particular or extreme environmental conditions, it may be necessary for certain dimensions to be changed and insulator units having different creepage distances, spacing and forms may be preferred (for example, flat profile, hemispherical etc.). Insulators for use on d.c. systems may also need different dimensions. In any case, it is recommended that the standardized mechanical characteristics of the present International Standard and coupling sizes are retained.
Except for nominal spacing, tolerances for dimensions indicated in lEG 383-1 are applicable to all nominal values including maximum nominal diameter and minimum nominal creepage distance values given in tables I and 2.
Nominal spacing tolerance shall be:
± (0,03 P+ 03) mm.IEC-60305-1995