In industrial automation (IA) and process control, many analog and digital modules of programmable logic controllers (PLCs), distributed control systems (DCS), motor and valve drives, and sensor/actuator interfaces operate from a standardized, nominal 24 VDC supply. This supply is commonly distributed as a DC bus throughout the entire system. Data exchange between these modules is carried out via industrial network protocols such as Profibus, Modbus and Interbus—all of which utilize RS-485 as their physical layer. For both economic and convenience reasons, the 24 V bus and RS-485 bus are distributed through the same conduits. This means there is risk of short circuits between supply and data conductors in the case of insulation faults.