SF6, sulphur hexafluoride, has roughly three times the dielectric strength of air at the same pressure and excellent arc-quenching ability, so it fills most high-voltage circuit breakers and gas-insulated switchgear. It is also a greenhouse gas with a warming potential around 23,500 times that of CO2, so handling, leak detection and end-of-life recovery are tightly controlled. Gas density is monitored, with alarm and lockout stages if it leaks.
SF6 density alarm on breaker 3 again, top it up and get the leak camera on the flanges before it falls to lockout.
Also heard as
- sulphur hexafluoride
- sulfur hexafluoride
- SF6 gas
Related terms
Switchgear
Assemblies of breakers, switches, fuses, busbars and enclosures that control and protect power circuits.
Disconnector
Off-load switch that provides a visible isolating gap but is not built to make or break load current.
Breaking capacity
Highest fault current a circuit breaker or fuse can interrupt safely at its rated voltage.