Abstract: An actuating mechanism for a circuit breaker includes a pair of contacts supported relative to a frame. One of the contacts is supported on a contact arm which is displaceable about a pivot to open and close the contacts. A releasable latch holds a rotatable cradle arm in latched position against the bias of an over-center spring connected between the contact arm and the cradle arm to bias the contact arm into over-center positions. An actuating link is coupled with the contact arm. When the cradle arm is held in the latched position, movement of the link from a first position to a second position displaces the contact arm pivot over center, causing the over-center spring to move the contact arm to close the contacts.