Generator switch, comprising an encapsulation, which is at earth potential when the generator switch is in operation, an electrical conductor, which is arranged in an electrically insulated manner inside the encapsulation and is at high-voltage potential when the generator switch is in operation, a gravity-driven cooling device having an evaporator and a condenser arranged above the evaporator and a coolant, wherein the evaporator is thermally conductively connected to the electrical conductor and is therefore at high-voltage potential when the generator switch is in operation, and wherein the condenser is connected to the encapsulation and is therefore at earth potential when the generator switch is in operation, the evaporator is connected to the condenser by way of a line system having an insulator, so that, when the generator switch is in operation, coolant vapour can be conveyed from the evaporator to the condenser and liquid coolant can be conveyed from the condenser to the evaporator, the insulator has an insulating section with an upper end, the line system has a coolant line, which connects a coolant outlet of the condenser to a coolant inlet of the evaporator, and furthermore has a coolant vapour line, which connects a coolant vapour outlet of the evaporator to a coolant vapour inlet of the condenser, in such a way that a closed cooling circuit is formed, characterized in that the closed cooling circuit is formed in the form of a ring, when the generator switch is in operation, a level of the liquid coolant in the line system, when the cooling device is inoperative, is at least as high as the upper end of the insulating section in the insulator, the insulator has a portion of the coolant line configured as a first insulating channel and a portion of the coolant vapour line configured as a second insulating channel, and the insulator has an insulating body that receives the two insulating channels (41, 42) and, for each insulating channel (41, 42), has a first connecting piece connected to the electrical conductor and a second connecting piece connected to the condenser. an encapsulation, which is at earth potential when the generator switch is in operation, an electrical conductor, which is arranged in an electrically insulated manner inside the encapsulation and is at high-voltage potential when the generator switch is in operation, a gravity-driven cooling device having an evaporator and a condenser arranged above the evaporator and a coolant, wherein the evaporator is thermally conductively connected to the electrical conductor and is therefore at high-voltage potential when the generator switch is in operation, and wherein the condenser is connected to the encapsulation and is therefore at earth potential when the generator switch is in operation, the evaporator is connected to the condenser by way of a line system having an insulator, so that, when the generator switch is in operation, coolant vapour can be conveyed from the evaporator to the condenser and liquid coolant can be conveyed from the condenser to the evaporator, the insulator has an insulating section with an upper end, the line system has a coolant line, which connects a coolant outlet of the condenser to a coolant inlet of the evaporator, and furthermore has a coolant vapour line, which connects a coolant vapour outlet of the evaporator to a coolant vapour inlet of the condenser, in such a way that a closed cooling circuit is formed, characterized in that the closed cooling circuit is formed in the form of a ring, when the generator switch is in operation, a level of the liquid coolant in the line system, when the cooling device is inoperative, is at least as high as the upper end of the insulating section in the insulator, the insulator has a portion of the coolant line configured as a first insulating channel and a portion of the coolant vapour line configured as a second insulating channel, and the insulator has an insulating body that receives the two insulating channels (41, 42) and, for each insulating channel (41, 42), has a first connecting piece connected to the electrical conductor and a second connecting piece connected to the condenser.