This standard applies to cast aluminium alloy enclosures pressurized with dry air, insert 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-quanching 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.