A method is disclosed for operating a circuit breaker, the circuit breaker. The circuit breaker includes an operating lever, a latching mechanism and an electrical contact system with a movable contact and a fixed contact. The operating lever is movable into an ON-position and an OFF-position. Further, the operating lever is mechanically connected via the latching mechanism to the contact system such that when the operating lever is in its OFF-position, the contacts of the electrical contact system are opened and when the operating lever is in its ON-position, the contacts of the electrical contact system are closed. Further, such a circuit breaker is also disclosed.

A contact system of a circuit breaker includes a fixed contact. The contact system also includes a moveable contact arm assembly comprising at least one moveable contact arm having a moveable contact thereon, the moveable contact arm moveable to define a closed condition and a blow open condition. The contact system further includes a carrier assembly operatively coupled to the moveable contact arm. The contact system yet further includes a latch plate operatively coupled to the carrier assembly. The contact system also includes a trip shaft operatively coupled to the carrier assembly, the trip shaft having a non-circular region defining an engagement surface disposed in contact with the latch plate in the closed condition. The contact system further includes a biasing portion of the moveable contact arm configured to rotate the trip shaft out of engagement with the latch plate and into the blow open condition.