What is SF6 Gas?

Substantial properties of sulfur hexafluoride at a glance

SF6 gas is colorless, odorless gas with a vapor density five times that of air. It is able to stay in vapor form (at normal operating temperatures) up to about 250 PSI. Some additional properties of SF6 which make it very desirable to the electrical utility sector are:

  • Colorless and odorless
  • 5 times heavier than air
  • Temperature-resistant up to 500 °C
  • Chemically stable
  • Non-toxic
  • Excellent dielectric properties
  • Non-inflammable 
  • Outstanding arc quenching properties

Where is SF6 gas used?

Sulfur hexafluoride is routinely used as an electrical and heat insulator in medium- and high-voltage T&D applications. These include: 

  • Circuit breakers
  • Switchgear
  • Power, voltage, and current transformers
  • Gas-insulated lines
  • Capacitors

How does SF6 gas work in an electrical breaker?

Because SF6 has excellent thermal transfer characteristics it works to absorb the energy of the arc, creating resistance across the arcing contacts and eventually extinguishing the arc. Once the arc is extinguished, sulfur hexafluoride begins to regenerate almost immediately.  

Why is SF6 gas the preferred insulator for breakers and switchgear?

SF6 is extremely effective at quenching the arcs created when electrical circuits are switched on or off. It also has a very high thermal conductivity, especially at high temperatures, which makes it more effective at dissipating heat then air, nitrogen, or other dielectrics. 


Unfortunately, the same properties that make SF6 an excellent insulating gas for GIE also make it a potent greenhouse gas. Quality gas handling products and well-trained technicians greatly reduce the risk of SF6 emissions. In addition to zero-emission SF6 gas handling equipment, DILO offers accredited SF6 gas safety and handling trainings.