Horrible Apartment Bulidng Fire In UK and Exploding Refrigerators.

[Chetlaham]

SF6 Circuit breakers

I hear you, switches are a different beast used only for isolation under no load. Fortunately the circuit breakers used in utility substations can safely interrupt high levels of fault current (see typical ratings here):

http://www.hitachi-tds.com/products/SF6_HS145kV_245kV_CB.html

https://en.wikipedia.org/wiki/Sulfur_hexafluoride_circuit_breaker

 

[tolivac]

TheSF6 breakers use a blast of SF6 gas while the circuit is being interrupted-so there is the difference rather than contacts in a pressurized SF6 gas filled container as in the isolation switches.One of our transmitters had a sealed SF6 breaker-this has been replaced with a vacuum contact one.We used to have to pressurize it occasionally from a small tank of SF6 gas.Now Progress Energy does this with our isolation switches.Remember a UHF TV station that pressurized their UHF antenna with SF6 gas.The antenna was handling 240Kw of transmitter power.9" nitrogen filled transmission line on the tower.5 Klystron transmitter-oh those old analog days!That has been long replaced-was quite something in 1972 when that system was installed by Harris.