This International Standard applies to composite hollow core station post insulators consisting of a load-bearing insulating tube (core) made of resin impregnated fibres an insulating filler material (e.g. solid, liquid, foam, gaseous – pressurized or unpressurized), a housing (outside the insulating tube) made of polymeric material (for example silicone or ethylene-propylene) and metal fixing devices at the ends of the insulating tube. Composite hollow core station post insulators as defined in this standard are intended for general use in substations in both, outdoor and indoor environments, operating with a rated AC voltage greater than 1000V and a frequency not greater than 100Hz or for use in direct current systems with a rated voltage greater than 1500V. The object of this standard is: to define the terms used; to prescribe test methods; to prescribe acceptance criteria. All the tests in this standard, apart from the thermal-mechanical test, are performed at normal ambient temperature. This standard does not prescribe tests that may be characteristic of the apparatus of which the composite hollow core station post insulator ultimately may form a part. Further technical input is required in this area. NOTE1 \'Pressurized\' means a permanent gas or liquid pressure greater than 0,05MPa (0,5bar) gauge. The gas can be dry air or inert gases, for example sulphur hexafluoride, nitrogen, or a mixture of such gases. NOTE2 \'Unpressurized\' means a gas or liquid pressure smaller than or equal to 0,05MPa (0,5bar) gauge.