Arc chute extension for increased interruption rating

摘要

A molded case circuit breaker having a spaced plate arc chute for each pole thereof, with each arc chute having a V-shaped mouth region at one end and having separable arcing contacts positioned at the mouth region and having a space defined opposite the mouth region and between a cover plate region and a terminal bus for obtaining access to terminal mounting bolts, is provided with at least one arc chute extension attached to a cover panel portion. Each arc chute extension consists of a plurality of spaced conductive plates and insulated means for rigidly positioning each of the plates in close planar alignment with a plate of the arc chute to present an increased length serpentine path for extinguishing an arc produced by the interruption of voltages and currents in excess of the original arc chute rating. Arc chute extensions are introduced as a single unit to increase the interruption rating of as many poles of the circuit breaker as is required.