This Standard applies to wrought steel enclosures and their welding. These enclosures are pressurized with dry air, inert gases, for example sulphur hexafluoride or nitrogen or a mixture of such gases, used in indoor and outdoor installations of high-voltage switchgear and controlgear with rated voltages above 1kV, 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 concerning gas-filled compartments with design pressure higher than 300 kPa relative pressure (gauge);
- above 52 kV concerning all gas-filled compartments.