This International Standard applies to composite station post insulators consisting of a load bearing cylindrical insulating solid core made of resin impregnated fibres, a housing (outside the insulating solid core) made of elastomer material (e.g. silicone or ethylene-propylene) and end fittings attached to the insulating core. Composite station post insulators covered by this standard are subjected to cantilever, torsion, tension and compression loads. They are intended for substations with a.c. voltages greater than 1 000 V up to 245 kV. The object of this standard is – to define the terms used, – to prescribe test methods, – to prescribe acceptance or failure criteria. This standard does not include requirements dealing with the choice of insulators for specific operating conditions.