This standard applies to cast aluminium alloy enclo-sures pressurized with dry air, inert gases, for example sulphur hexafluoride or nitrogen or a mixture of such gases, used in indoor or outdoor installations of high-voltage switchgear and controlgear with rated voltages above 1 kV, where the gas is used principally for its dielectric and/or arc-quenching properties.
The enclosures comprise parts of electrical equipment not necessarily limited to the following examples:
Circuit-breakers Switch-disconnectors Disconnectors Earthing switches Current transformers Voltage transformers Surge arrestors Busbars and connections
The scope also covers pressurized components such as the centre chamber of live tank switchgear, gas-insulated current transformers, etc. .