A switching device including a switching unit having one or more electric poles and including, for each electric pole, a first power contact and a second power contact along which a line current can circulate and one or more solid-state switches; and a supporting frame adapted to be fixed to a supporting structure and including, for each electric pole, a third power contact and a fourth power contact along which said line current can circulate. The switching unit is reversibly movable, with respect to said supporting frame, between an insertion position and a withdrawn position. The switching unit includes, for each electric pole, at least a hydraulic circuit along which a cooling fluid can circulate to remove heat generated by said solid-state switches. The hydraulic circuit includes a first hydraulic connector and a second hydraulic connector that are coupled with or separated from a corresponding third hydraulic connector and a corresponding fourth hydraulic connector of said supporting frame, when said switching unit is in said insertion position or in said withdrawn position.