An electric switching device for an electric circuit, including at least one electric phase having at least one circuit breaking unit associated with a disconnector unit. The circuit breaker unit including a circuit breaker movable contact configured to be actuated between a closed position and an open position with respect to a corresponding circuit breaker fixed contact. The disconnector unit includes at least one disconnector movable contact configured to be actuated between a connection position and a disconnection position with respect to a corresponding disconnector fixed contact. A casing that includes an insulating shell coupled to a metal shell. The casing houses at least the circuit breaker unit and the associated disconnector unit of said at least one electric phase.