Abstract: This electric circuit breaker comprises a plurality of vacuum-type circuit interrupters electrically connected in parallel with each other and means for opening the interrupters substantially simultaneously during circuit interruption. Each interrupter comprises an evacuated envelope and a pair of relatively-movable contacts located within the envelope to provide an inter-contact gap across which arcing can occur during circuit interruption. The stationary contacts of the two interrupters are respectively mounted on stationary contact rods that have their outer ends closely adjacent each other. A communicating passageway extends between the two inter-contact gaps through the stationary contacts and the stationary contact rods for conveying arcing products from any inter-contact gap that is then arcing to any that is not then arcing, thereby promoting concurrent arcing at said gaps during high-current interruptions.

Abstract: This electric circuit breaker comprises a plurality of vacuum-type circuit interrupters electrically connected in parallel with each other and means for opening the interrupters substantially simultaneously during circuit interruption. Each interrupter comprises an evacuated envelope and a pair of relatively-movable contacts located within said envelope that are separable to provide an inter-contact gap across which arcing usually occurs during circuit interruption. The envelope comprises a tubular metal wall portion surrounding the inter-contact gap and a radially-extending opening within this tubular metal wall portion. The metal wall portions of the two interrupters are located in closely adjacent side-by-side relationship, and a short metal tube provides a passage between said openings for conveying arcing products from any inter-contact gap that is then arcing to any that is not then arcing, thereby promoting concurrent arcing at said gaps during high current interruptions.