The invention relates to a motor vehicle supply network (2), in particular a 48V on-board power supply of a motor vehicle, comprising a current source (14), a power distributor (12) connected to the current source (14) via a supply current path (16), and at least one load (6) connected to the power distributor (12) via a load current path (4) with an integrated semiconductor switch (18), wherein a current-measuring unit (20), a voltage-measuring unit (22) and a monitoring unit (26) are integrated into the power distributor (12), and wherein the monitoring unit (26) is designed in such a way that same detects an imminent fault based on the measurement data of the current-measuring unit (20) and/or the measurement data of the voltage-measuring unit (22), and in such a way that same initiates a switching-off of the at least one load (6) using the semiconductor switch (18), wherein both imminent over-current faults and imminent arc faults are detected as an imminent fault.