A gas-insulated puffer-type switch device for operating inside a sealed gas tight enclosure of an electric power distribution switchgear, the sealed gas tight enclosure being filled with a dielectric gas having a global warming potential lower than that of SF6, the switch device comprising: a stationary contact assembly; a movable contact assembly, longitudinally movable along an axis of the movable contact assembly between a closed state of the switch device in which the movable contact assembly is in electrical connection with the stationary contact assembly and an open state of the switch device in which the movable contact assembly is not in electrical connection with the stationary contact assembly; a switch actuator mechanism for transmitting a rotational movement of an actuation shaft to a longitudinal movement of the movable contact assembly; an earthing switch; a first terminal electrically connected to the movable contact assembly by a first conductive line, the first conductive line comprising a flexible conductor for accommodating the longitudinal movement of the movable contact assembly; a second terminal electrically connected to the stationary contact assembly; an electrically conductive first housing enclosing at least a portion of the movable contact assembly, thereby electrically shielding the movable contact assembly when the switch device is in the open state, the first housing further enclosing the switch actuator mechanism and at least a portion of the earthing switch, wherein the first housing comprises ventilation openings for allowing a convective stream of the dielectric gas from outside of the first housing through the first housing, and characterized in that the first terminal is electrically connected to the earthing switch by a second conductive line; the first housing encloses the first conductive line, and at least a portion of at least one of the first terminal, the first conductive line, and the second conductive line is thermally conductively connected to the first housing. a stationary contact assembly; a movable contact assembly, longitudinally movable along an axis of the movable contact assembly between a closed state of the switch device in which the movable contact assembly is in electrical connection with the stationary contact assembly and an open state of the switch device in which the movable contact assembly is not in electrical connection with the stationary contact assembly; a switch actuator mechanism for transmitting a rotational movement of an actuation shaft to a longitudinal movement of the movable contact assembly; an earthing switch; a first terminal electrically connected to the movable contact assembly by a first conductive line, the first conductive line comprising a flexible conductor for accommodating the longitudinal movement of the movable contact assembly; a second terminal electrically connected to the stationary contact assembly; an electrically conductive first housing enclosing at least a portion of the movable contact assembly, thereby electrically shielding the movable contact assembly when the switch device is in the open state, the first housing further enclosing the switch actuator mechanism and at least a portion of the earthing switch, wherein the first housing comprises ventilation openings for allowing a convective stream of the dielectric gas from outside of the first housing through the first housing, and characterized in that the first terminal is electrically connected to the earthing switch by a second conductive line; the first housing encloses the first conductive line, and at least a portion of at least one of the first terminal, the first conductive line, and the second conductive line is thermally conductively connected to the first housing.