Stacked circuit breakers having high interrupting capacity

摘要

A multipole molded case circuit breaker of moderately high rating is constructed of a stack of single pole units each having a contact operating mechanism and a trip unit. The movable contact arm is so positioned that it is subjected to magnetic blow-off effect, which even at relatively low fault levels, tend to open the contacts to enduce a current limiting action. A conducting strap within each pole unit housing is connected to the line terminal and is provided with a plurality of spaced connecting points each accessible through a different opening at the rear of the housing for connection to a panelboard bus bar.