A motor vehicle supply network, in particular a 48V on-board power supply of a motor vehicle, contains a current source, a power distributor connected to the current source via a supply current path, and at least one load connected to the power distributor via a load current path with an integrated semiconductor switch. A current-measuring unit, a voltage-measuring unit and a monitoring unit are integrated into the power distributor. The monitoring unit is configured in such a way that same detects an imminent fault based on the measurement data of the current-measuring unit and/or the measurement data of the voltage-measuring unit, and in such a way that same initiates a switching-off of the at least one load using the semiconductor switch. Both imminent over-current faults and imminent arc faults are detected as an imminent fault.