A low-voltage circuit breaker device includes: a first outer conductor line and at least one first bypass line, the first outer conductor line being arranged in the circuit in parallel to the at least one first bypass line; a first mechanical bypass switch arranged in the first outer conductor line; first semiconductor circuit assembly connected in parallel to the first bypass switch; a second semiconductor circuit assembly arranged in the circuit in series with the first bypass switch and parallel to the first semiconductor circuit assembly in the first outer conductor line; a first current measuring assembly, which is connected to a first electronic control unit, arranged in the first outer conductor line, the first electronic control unit being arranged to actuate the first bypass switch, the first semiconductor circuit assembly, and the second semiconductor circuit assembly; and a second mechanical bypass switch arranged in the first bypass line.