CIRCUIT BREAKER AND METHOD

A circuit breaker protects an electric low-voltage circuit. The circuit breaker contains a housing with a grid-side connection and a load-side connection, and a mechanical separating contact unit which is connected to an electronic interruption unit in series. The mechanical separating contact unit can be switched by opening contacts to prevent a current flow or by closing the contacts for a current flow in the low-voltage circuit. Due to switching elements, the electronic interruption unit can be switched to a high-ohmic state of the switching elements to prevent a current flow or to a low-ohmic state of the switching elements for a current flow in the low-voltage circuit. The level of the current in the low-voltage circuit is ascertained. A process for preventing a current flow in the low-voltage circuit is initiated if current thresholds and/or current/time thresholds are exceeded.