Abstract: A circuit breaker is provided with an elongated movable contact arm pivotally mounted at one of its ends, the movable contact secured to its other end, and the contact operating mechanism connected to the contact arm at a point intermediate the ends thereof. Breaking of contact welds is facilitated by constructing the contact arm pivot of a fixed pin which extends through an elongated slot in the contact arm so that during initial opening motion of the contact arm the latter will pivot about the point of engagement between the movable and stationary contacts as the slot moves relative to the pin and in this way a levered prying action is obtained to facilitate the breaking of welds formed between the contacts.