A so-called blow-off type current limiting circuit breaker is provided with an elongated movable contact arm that is pivotally mounted at one end thereof on a pin that projects from opposite sides of a support. The contact arm is constructed of parallel sections that are biased toward one another, by spring means disposed remote from the support, with the support being resiliently clamped between the sections to provide a good electrical connection between the support and contact arm. The pivot pin extends through aligned enlarged pivot apertures in the parallel sections to facilitate weld breaking. A wall of each pivot aperture is disposed to cooperate with the pivot pin to achieve a camming action that moves the contact arm slightly lengthwise after initial butting engagement of the circuit breaker main contacts to wipe the engaged contacts with respect to one another.