Auxiliary switches report the status of the main devices on which they are mounted. The devices in the DHi 2 series are auxiliary switches or fault signal switches for the residual current circuit breakers in the DFS series, whereby the DHi 2 is suitable for RCCBs with a black toggle. They make it possible to display the operating status of a residual current circuit breaker with the help of additional output devices (e.g. buzzers or indicator lights) or via control systems. The function is set using an actuator on the DHi. In the 'auxiliary switch' operating mode, they signal the switching on and off of the RCCB. In the 'fault signal switch' operating mode, they only signal tripping. Properties: Auxiliary switch or fault signal switch function, can be retrofitted to residual current circuit breakers in the DFS series, small size, mounting type: to the left of the base device using clamps, quick attachment to a mounting rail, any installation position, areas of application: These devices are suitable for querying the operating status of power supplies in residential and commercial buildings as well as industrial plants. Notes: The auxiliary switch does not affect the function of the base unit.