English: A 3 phase 115 kV 1200 A circuit breaker, SF 6 type, mounted outdoors at the substation near the Manitoba Hydro Slave Falls generating station. Current enters and leaves the breaker through the bare wire leads terminating on the top of the insulator bushings. The horizontal cylindrical tanks contain the interrupters which operate in an envelope filled with sulfur hexafluoride (SF6) gas. The control cabinet for the breaker is on the left side of the unit, which contains the mechanism that opens and closes all three poles at the same time. Unlike smaller breakers used in low voltage systems, the over current sensing relays are always separately mounted in this form of breaker. Part of the steel lattice structure of the station can be seen, as well as part of another breaker at the left side of the picture. Picture taken from en:Circuit breaker.