High-voltage circuit-interrupters

A high-voltage circuit-interrupter having a contact arrangement for operation within an enclosure containing an insulating fluid medium, the interrupter comprising a pair of tubular fixed contacts having adjacent ends spaced apart, and each fixed contact including a bore containing a rooting electrode in electrical connection with the fixed contact, and at least one of the rooting electrodes being movable within its fixed contact to engage with and disengage from the other rooting electrode, and an external movable bridging contact which retractibly engages and electrically bridges the spaced adjacent ends of the fixed contacts, circuit-breaker operating means for moving the bridging contact clear of the end of one of the fixed contacts and for introducing a jet stream of the insulating medium at higher pressure than that in the interiors of the fixed contacts through the gap between the ends of the fixed contacts and into the interiors thereof, the spaced adjacent end of each of the tubular fixed contacts includes an arc-resistant insulating nozzle having an internal bore diverging in a direction downstream of the jet stream and away from the end of the respective fixed contact, and the circuit-breaker operating means operating at least one movable rooting electrode to separate the rooting electrodes so that the jet stream of the higher-pressure medium is directed at an arc drawn between the separated rooting electrodes.