A switching installation including a gas-filled enclosure, an input conductor, an actuator and a short-circuit device. The actuator is arranged to actuate the short-circuit device upon the occurrence of a first arc in the enclosure. The short-circuit device creates, upon being actuated, a short-circuit through the solid insulation between the input conductor and the enclosure or a separate ground point. The actuator can be arranged to react on an increase in pressure in the enclosure upon the occurrence of the first arc. The gas can be air or SF6. The short-circuit device can create, upon being actuated, the short-circuit through a section of a solid cable insulation isolating the input conductor from the enclosure.