A switching apparatus for medium voltage electric systems, said switching apparatus comprising one or more electric poles, wherein, for each electric pole, said switching apparatus comprises: - a first pole terminal, a second pole terminal and a ground terminal, said first pole terminal being electrically couplable with a first conductor of an electric line, said second pole terminal being electrically couplable to a second conductor of said electric line and said ground terminal being electrically couplable to a grounding conductor; - a plurality of fixed contacts spaced apart one from another, said plurality of fixed contacts comprising a first fixed contact electrically connected to said first pole terminal, a second fixed contact electrically connected to said second pole terminal, a third fixed contact electrically connected to said ground terminal and a fourth fixed contact; - a movable contact reversibly movable about a corresponding rotation axis according to opposite first and second rotation directions (R1, R2), so that said movable contact can be coupled to or uncoupled from said fixed contacts (5, 6, 7, 8); - a vacuum interrupter comprising a fixed arc contact electrically connected to said first pole terminal, a movable arc contact electrically connected to said fourth fixed contact and reversibly movable along a corresponding translation axis between a coupled position with said fixed arc contact and an uncoupled position from said fixed arc contact and a vacuum chamber, in which said fixed arc contact and said movable arc contact are enclosed and can be coupled or decoupled; - a motion transmission mechanism operatively coupled to said movable arc contact, said motion transmission mechanism being actuatable by said movable contact to cause a movement of said movable arc contact along said translation axis, when said movable contact moves about said rotation axis; characterised in that said motion transmission mechanism comprises a first lever element pivoted on a fixed support at a first hinge point and a second lever element pivoted on a said movable arc contact at a second hinge point, said first and second lever elements (31, 32) being pivoted one on another at a third hinge point. - a first pole terminal, a second pole terminal and a ground terminal, said first pole terminal being electrically couplable with a first conductor of an electric line, said second pole terminal being electrically couplable to a second conductor of said electric line and said ground terminal being electrically couplable to a grounding conductor; - a plurality of fixed contacts spaced apart one from another, said plurality of fixed contacts comprising a first fixed contact electrically connected to said first pole terminal, a second fixed contact electrically connected to said second pole terminal, a third fixed contact electrically connected to said ground terminal and a fourth fixed contact; - a movable contact reversibly movable about a corresponding rotation axis according to opposite first and second rotation directions (R1, R2), so that said movable contact can be coupled to or uncoupled from said fixed contacts (5, 6, 7, 8); - a vacuum interrupter comprising a fixed arc contact electrically connected to said first pole terminal, a movable arc contact electrically connected to said fourth fixed contact and reversibly movable along a corresponding translation axis between a coupled position with said fixed arc contact and an uncoupled position from said fixed arc contact and a vacuum chamber, in which said fixed arc contact and said movable arc contact are enclosed and can be coupled or decoupled; - a motion transmission mechanism operatively coupled to said movable arc contact, said motion transmission mechanism being actuatable by said movable contact to cause a movement of said movable arc contact along said translation axis, when said movable contact moves about said rotation axis;