The present invention relates to a molded-case circuit breaker for direct current (DC), and more particularly, to a molded-case circuit breaker for DC in which a connecting conductor for connecting terminals in the DC circuit breaker is configured as an assembly unit and contained in a terminal receiving portion to improve insulation performance and assemblability and reduce occupied space. There is provided a molded-case circuit breaker for DC that contains a plurality of interruption units, the DC circuit breaker including a terminal connecting unit that connects terminals of adjacent interruption units, the terminal connecting unit being placed within a terminal receiving portion on the front or rear of an outer casing of the circuit breaker.

The present invention relates to a molded-case circuit breaker for direct current (DC), and more particularly, to a molded-case circuit breaker for DC that contains an internal connecting conductor connecting adjacent terminals to improve insulation performance and assemblability and reduce occupied space. There is provided a molded-case circuit breaker for DC that contains a plurality of interruption units within an outer casing, the DC circuit breaker including a two-unit connecting heater that connects fixed contacts of adjacent interruption units, the two-unit connecting heater being placed within the outer casing.

An electrical protection device, including a movable contact, connected to an electrical circuit, a switching handle, and an electronic control unit. The device further includes an electrical link element, connecting the movable contact and the electronic control unit, a switch, a mechanical link element, connected to the switching handle. The electronic control unit is configured to measure the first voltage and the second voltage, compare the first voltage and the second voltage to determine the cause of opening of the electrical circuit among manual opening and fault opening, send a first signal if the cause of opening is manual opening and send a second and/or third signal if the cause of opening is fault opening.

An electrical protection device, including a movable contact, connected to an electrical circuit, a switching handle, and an electronic control unit. The device further includes an electrical link element, connecting the movable contact and the electronic control unit, a switch, a mechanical link element, connected to the switching handle. The electronic control unit is configured to measure the first voltage and the second voltage, compare the first voltage and the second voltage to determine the cause of opening of the electrical circuit among manual opening and fault opening, send a first signal if the cause of opening is manual opening and send a second and/or third signal if the cause of opening is fault opening.

The instant trip apparatus of the molded case circuit breaker includes a case, a magnet part disposed in the case to generate magnetic attractive force when accident current flows therethrough, an armature disposed to face the magnet part, the armature rotating to the magnet part by the magnetic attractive force, an armature spring for allowing the armature to elastically return to its original position when the magnetic attractive force is removed, and a gap maintenance part restricting the rotation of the armature so that a gap defined between the armature and the magnet part is maintained when the accident current occurs. The gap maintenance part includes a rotation restriction member that is disposed to be exposed to an armature rotation path between the armature and the magnet part. Thus, fusion between the armature and the magnet part due to the accident current occurs may be prevented.