An electromagnet device is configured to generate a magnetic attractive force between a stationary core and a movable core when electricity is applied to a coil, so that the movable core is moved in a direction for coming into contact with the stationary core, and a movable shaft is moved in a direction in which a first end face of the movable shaft separates from a movable terminal. After the movable contact comes in contact with the fixed contact, the movable core moves further in a direction for coming into contact with the stationary core. A yoke made of a magnetic body is disposed between the movable terminal and the first end of the movable shaft.

An electromagnet device is configured to generate a magnetic attractive force between a stationary core and a movable core when electricity is applied to a coil, so that the movable core is moved in a direction for coming into contact with the stationary core, and a movable shaft is moved in a direction in which a first end face of the movable shaft separates from a movable terminal. After the movable contact comes in contact with the fixed contact, the movable core moves further in a direction for coming into contact with the stationary core. A yoke made of a magnetic body is disposed between the movable terminal and the first end of the movable shaft.

A circuit breaker for protecting an electric circuit contains a housing and an adapter having a receiving connector. The circuit breaker has two electrically conductive, substantially cylinder-shaped connection points which are positioned along an axis. Either the outer diameter of the connection points is between 5.0 mm and 5.3 mm and the maximum distance between the connection points is between 19.0 mm and 21.0 mm, or the outer diameter of the connection points is between 6.2 mm and 6.5 mm and the maximum distance between the connection points is between 30.5 mm and 33.0 mm.