This standard applies to cast aluminium alloy enclosures 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 above 1 kV, where the gas is used principally for its dielectric and/or arc quenching properties with rated voltajes - above 1 kV and up to and including 52 kV and with gas-filled compartments with design pressure higher than 300 kPa relative pressure (gauge); - and with rated voltage above 52 kV. - Circuit-breakers; - Switch-disconnectors; - Disconnectors; - Earthing switches; - Current transformers; - Voltage transformers; - Surge arrestors; - Busbars and connections; - etc. The scope also covers enclosures of pressurized components such as the centre chamber of live tank switchgear, gas-insulated current transformers, etc.