Abstract: A high voltage sulfur hexafluoride circuit-breaker capable of operating at low outside temperatures and comprising at least one current-interrupting chamber comprising a sealed insulating enclosure containing a fixed contact inside a blast nozzle and a set of moving contacts associated with an operating member, the circuit-breaker including the improvement of means for maintaining a quantity of liquefied gas in the vicinity of the contact separation zone while the circuit-breaker is in the closed position.

Abstract: A sulfur hexafluoride circuit-breaker for operating in a very low temperature environment, the circuit-breaker being of the type comprising a sealed enclosure filled with sulfur hexafluoride and closed by first and second end plates, a set of fixed contacts, a set of moving contacts driven by an operating rod, a blast volume which is mechanically compressed when the operating rod is displaced to open the circuit-breaker, and blast nozzle for directing the said compressed gas from said volume onto the arc, the circuit-breaker including the improvement of means for creating an arc in said blast volume during a portion of the time that the moving assembly is moving, by diverting the current to be interrupted so that it flows through two parts constituting two electrodes.