A safety switching device for fail-safely switching on and off an electrical load, and to a system comprising at least two safety switching devices which interact in a fail-safe manner via a single-channel. The safety switching device comprises a fail-safe control unit, a first and a second electronic switching element connected with a first and a second output terminal; and at least one input terminal for receiving a first switching signal that causes a switching of said switching elements. Said first and second switching elements each comprise an output which provides depending on the first switching signal an output signal having a first or second potential. A third output terminal connects said safety switching device to a second safety switching device, providing a clocked signal depending on the first switching signal and being monitored by said control unit for performing a cross fault detection.