A switching device comprising: - a switching unit having one or more electric poles and comprising, 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 electrically connected with said first and second power contacts and switchable in a conduction state or in an interdiction state to allow or interrupt a flow of said line current; - a supporting frame adapted to be fixed to a supporting structure and comprising, for each electric pole, a third power contact and a fourth power contact along which said line current can circulate, wherein, in operation, said switching unit is reversibly movable, with respect to said supporting frame , between an insertion position (A) and a withdrawn position (B), wherein said first power contact and said second power contact are coupled with said third power contact and said fourth power contact , respectively, when said switching unit is in said insertion position (A), wherein said first power contact and said second power contact are separated from said third power contact and said fourth power contact , respectively, when said switching unit is in said withdrawn position (B); characterised in that : - said switching unit comprises, for each electric pole, at least a first hydraulic connector and a second hydraulic connector along which a cooling fluid adapted to remove heat generated by said solid-state switches can circulate; - said supporting frame comprises at least a third hydraulic connector and a fourth hydraulic connector along which said cooling fluid can circulate; wherein said first hydraulic connector and said second hydraulic connector are coupled with said third hydraulic connector and said fourth hydraulic connector , respectively, when said switching unit is in said insertion position (A), wherein said first hydraulic connector and said second hydraulic connectors are separated from said third hydraulic connector and said fourth hydraulic connector , respectively, when said switching unit is in said withdrawn position (B). - a switching unit having one or more electric poles and comprising, 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 electrically connected with said first and second power contacts and switchable in a conduction state or in an interdiction state to allow or interrupt a flow of said line current; - a supporting frame adapted to be fixed to a supporting structure and comprising, for each electric pole, a third power contact and a fourth power contact along which said line current can circulate, wherein, in operation, said switching unit is reversibly movable, with respect to said supporting frame , between an insertion position (A) and a withdrawn position (B), wherein said first power contact and said second power contact are coupled with said third power contact and said fourth power contact , respectively, when said switching unit is in said insertion position (A), wherein said first power contact and said second power contact are separated from said third power contact and said fourth power contact , respectively, when said switching unit is in said withdrawn position (B); - said switching unit comprises, for each electric pole, at least a first hydraulic connector and a second hydraulic connector along which a cooling fluid adapted to remove heat generated by said solid-state switches can circulate; - said supporting frame comprises at least a third hydraulic connector and a fourth hydraulic connector along which said cooling fluid can circulate; <EOS>