This European 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 voltages-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.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;-etc.The scope also covers enclosures of pressurized components such as the centre chamber of live tank switchgear, gas-insulated current transformers, etc.