Circuit breaker and method

A circuit breaker for protecting an electrical low-voltage circuit, the circuit breaker comprising:

• a housing having connections for conductors of the electrical low-voltage circuit,
• a current sensor for ascertaining a level of a current of the electrical low-voltage circuit;
• a mechanical isolating contact unit having contacts and an open state of said contacts preventing a current flow in the electrical low-voltage circuit or a closed state of said contacts allowing the current flow in the electrical low-voltage circuit;
• an electronic interruption unit having semiconductor-based switching elements, said electronic interruption unit connected in series with said mechanical isolating contact unit on a circuit side and which, as a result of said semiconductor-based switching elements, having a high-impedance state of said semiconductor-based switching elements to prevent the current flow or a low-impedance state of said semiconductor-based switching elements for allowing the current flow in the electrical low-voltage circuit;
• and
• a controller connected to said current sensor, to said mechanical isolating contact unit and to said electronic interruption unit, wherein if at least one current limit value or current-time limit value is exceeded a process for preventing the current flow in the electrical low-voltage circuit is initiated, wherein a manner of preventing the current flow in the electrical low-voltage circuit is configurable based on at least one parameter being exceeded or undershot, and wherein said manner of preventing the current flow in the electrical low-voltage circuit is configured to be the high-impedance state of said semiconductor-based switching elements of said electronic interruption unit or the open state of said contacts of said mechanical isolating contact unit.