FAST EARTHING SWITCH FOR INTERRUPTING NON-SHORT-CIRCUIT CURRENTS

The invention relates to a fast earthing switch (1) for interrupting non-short-circuit currents comprisingtwo contacts (2) of which at least one contact (2) is movable in relation to the other contact between a closed position, in which the contacts (2) are connected, and an open position, in which the contacts (2) are unconnected, said contacts (2) defining an arcing region in which an arc is generated during a current interrupting operation and in which an arc-quenching medium is present,a cylinder-like guiding tube (3) in which the at least one movable contact (2) forming a piston (4) is slidably arranged for linearly moving between the closed position and the open position, wherebythe guiding tube (3) is closed at an upper end (5) and/or at a thereto opposite lower end (6) so that that the piston (4) defines a first compression chamber (9) with the upper end (5) and/or a second compression chamber (10) with the lower end (6) for thereby decelerating movement of the piston (4) when moving into the open position and/or into the closed position.