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 electrically couplable to a grounding conductor; - a first fixed contact member and a first movable contact member, said first fixed contact member being electrically connected to said first pole terminal and including a first fixed contact, said first movable contact member being electrically connected to said second pole terminal and including a first movable contact, said first movable contact member being reversibly movable about a corresponding first rotation axis, so that said first movable contact can be coupled to or uncoupled from said first fixed contact or said ground terminal; - a second fixed contact member and a second movable contact member, said second fixed contact member being electrically connected to said first pole terminal and including a second fixed contact, said second movable contact member including a second movable contact and being reversibly movable, along a corresponding translation axis, so that said second movable contact can be coupled to or uncoupled from said second fixed contact; - a vacuum chamber, in which said second fixed contact and said second movable contact are enclosed and can be coupled or decoupled; whereby for each electric pole, said switching apparatus comprises a motion transmission mechanism for actuating said second movable contact member and including: - a cam member movable about a second rotation axis and coupled to said second movable contact member, wherein said cam member exerts on said second movable contact member actuation forces moving said second movable contact member along said translation axis, when said cam member rotates about said second rotation axis, wherein said cam member is electrically conductive and electrically connected to said second movable contact member; - a first lever arm coupled to said cam member and extending radially with respect to said second rotation axis, wherein said first lever arm is electrically conductive and electrically connected to said second movable contact member; characterised by: - a second lever arm coupled to said cam member and extending radially with respect to said second rotation axis and angularly spaced with respect to said first lever arm; wherein said cam member is movable between a first switch position, which corresponds to a coupling position of said second movable contact member with said second fixed contact member, and a second switch position, which corresponds to a decoupled position of said second movable contact member from said second fixed contact member, upon actuation of said first lever arm or said second lever arm by said first movable contact member, during an opening or closing manoeuvre of said switching apparatus. - 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 electrically couplable to a grounding conductor; - a first fixed contact member and a first movable contact member, said first fixed contact member being electrically connected to said first pole terminal and including a first fixed contact, said first movable contact member being electrically connected to said second pole terminal and including a first movable contact, said first movable contact member being reversibly movable about a corresponding first rotation axis, so that said first movable contact can be coupled to or uncoupled from said first fixed contact or said ground terminal; - a second fixed contact member and a second movable contact member, said second fixed contact member being electrically connected to said first pole terminal and including a second fixed contact, said second movable contact member including a second movable contact and being reversibly movable, along a corresponding translation axis, so that said second movable contact can be coupled to or uncoupled from said second fixed contact; - a vacuum chamber, in which said second fixed contact and said second movable contact are enclosed and can be coupled or decoupled; whereby for each electric pole, said switching apparatus comprises a motion transmission mechanism for actuating said second movable contact member and including: - a cam member movable about a second rotation axis and coupled to said second movable contact member, wherein said cam member exerts on said second movable contact member actuation forces moving said second movable contact member along said translation axis, when said cam member rotates about said second rotation axis, wherein said cam member is electrically conductive and electrically connected to said second movable contact member; - a first lever arm coupled to said cam member and extending radially with respect to said second rotation axis, wherein said first lever arm is electrically conductive and electrically connected to said second movable contact member; - a second lever arm coupled to said cam member and extending radially with respect to said second rotation axis and angularly spaced with respect to said first lever arm;