Circuit breaker

A circuit breaker device for protecting an electric low-voltage circuit, comprising:

• a housing having a grid-side neutral conductor connection, a grid-side phase conductor connection, and a load-side phase conductor connection for the low-voltage circuit;
• a mechanical isolating contact unit connected in series with an electronic interruption unit for a phase conductor path, said mechanical isolating contact unit being connected to said load-side phase conductor connection, and said electronic interruption unit being connected to said grid-side phase conductor connection;
• a current sensor unit for ascertaining a level of a current of the phase conductor path;
• a first voltage sensor unit for ascertaining a level of a voltage across two connections of said electronic interruption unit;
• a power supply unit connected, or to be connected, to said grid-side neutral conductor connection and to said grid-side phase conductor connection;
• a control unit connected to said power supply unit, to said current sensor unit, to said mechanical isolating contact unit, and to said electronic interruption unit, and wherein a process for interrupting a current flow in the phase conductor is initiated when the current in the phase conductor exceeds a threshold value or a current/time threshold value;
• and
• said electronic interruption unit being configured to be switched, via semiconductor-based switching elements, to a high-impedance state of the switching elements to prevent a flow of current or to a low-impedance state of the switching elements for the flow of current in the low-voltage circuit.