Welded Composite Enclosures of Cast and Wrought Aluminium Alloys for Gas-Filled High-Voltage Switchgear and Controlgear

2.1 Type of Equipment

This Standard applies to welded composite enclosures of cast and wrought aluminium and aluminium alloy enclosures pressurized with dry air, inert gases, eg, sulphur hexafluoride, carbon tetrafluoride, or nitrogen or a mixture of such gases, used in indoor or outdoor installations of high-voltage switchgear and controlgear, where the gas is used principally for its dielectric and/or arc-quenching properties, with rated voltages:

a) 1 kV and up to and including 52 kV and with gas-filled compartments with design pressure greater than 3 bar (gauge); and
b) 72.5 kV and above. 

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 arresters;
- Busbars and connections. 

The scope covers also pressurized components such as the centre- chamber of live tank switchgear and controlgear, gas-insulated current transformers, etc. 

2.2 Production
The production of the enclosures shall be in accordance with documented welding procedures which shall be carried out by well trained and supervised welding personnel. Where international standards (ISO or CEN) are not available, National Standards may be used. 

NOTE - This Standard will be revised as soon as possible when ISO or CEN standards covering the various aspects are available. 

2.3 Quality Assurance

It is the intention of this standard, that the switchgear manufacturer shall be responsible for achieving and maintaining a consistent and adequate quality of product. 

Sufficient examinations shall be made by the enclosure manufacturer to ensure that the materials, production and testing comply in all respects with the requirements of this standard and ISO 6213:1983. Inspection by the user's inspectors shall not absolve the switchgear manufacturer from his responsibility to exercise such quality assurance procedures as to ensure that the requirements and the intent of this standard are satisfied. 

NOTE - The manufacturer should have a quality assurance program registered to the applicable ISO 9000 series Standards.