Selective automatic safety switch

Safety switch for the selective protection of electrical installations, comprising a self-closing first switching unit (12) and a first actuation device (13) interacting with the latter for undelayed opening of the first switching unit (12) in the case of a short-circuit current, a second switching unit (17) connected in series with the first switching unit (12) and a second actuation device (20) interacting with the second switching unit (17) for delayed opening of the second switching unit (17) in the case of an overload current, and a third actuation device (24) interacting with the second switching unit (17) for delayed opening of the second switching unit (17) in the case of the occurrence of a short-circuit current, which third actuation device (24) is connected to a shunt path (26) which comprises current-limiting means (27) and which bridges at least the first switching unit (12). Because the first switching unit (12) is provided with delay means (28) for keeping said first switching unit (12) open for an adjustable period of time, the switch-selective action of the safety switch can be accurately set.