scope:

This standard covers the design, testing, and installation of metal-enclosed switchgear that incorporates gas (typically SF₆) at higher than ambient pressure as an insulation medium for alternating-current applications rated above 1 kV to 52 kV. Contents of switchgear may include but are not limited to circuit breakers, switches, bushings, buses, instrument transformers, cable terminations, instrumentation, metering and controls, and protective relays. In a vertical section of the switchgear, some or all of the medium-voltage compartment(s) shall be comprised of a gas pressure system for the primary insulating medium.

This standard covers both indoor and outdoor installations. This standard covers switchgear using sealed pressure systems or closed pressure systems. Switchgear employing controlled pressure systems are not covered by this standard.

This standard does not cover switchgear that is covered under IEEE Std.C37.20.2, IEEE Std.C37.20.3 or IEEE Std. C37.74 [B27] that uses individual components that are gas-insulated such as switches, circuit breakers and other equipment, nor does it fully cover those components which are covered by their individual component standards.