Circuit breaker

A circuit breaker comprising:

• a fixed contact,
• a rotatable contact,
• a contact holder supporting the rotatable contact,
• an operation handle moving between an ON position and an OFF position for opening and closing the rotatable contact,
• an over-current tripping device for performing a tripping operation in response to an over-current and having a latch,
• a switching device including a handle lever connected to the operation handle and having a support point at an end thereof;
• a toggle linkage interposed between the contact holder and the latch and having a connecting pin, and upper and lower links connected by the connecting pin;
• a spring disposed between the handle lever and the connecting pin;
• and a side plate for supporting the handle lever, the toggle linkage and the spring, and
• means for preventing the operation handle from moving to the OFF position when the movable contact is stuck to the fixed contact, said means including first stoppers formed on a cross bar of the contact holder and the handle lever facing the cross bar, respectively, and a second stopper formed on the side plate of the switching device for preventing a movement of the operation handle to the OFF position.