A system and method for preventing bus voltage sagging when an Oring-FET in an N+1 redundant power supply configuration is faulty during power up. Each redundant power supply includes an Oring-FET and a voltage comparator. The voltage comparator receives and compares an input voltage and an output voltage of the Oring-FET during power up. In the event input voltage is less than the output voltage, the Oring-FET is deemed to be operating properly and provides output to a communicatively coupled system bus in response to the input voltage reaching a predetermined voltage threshold level. In the event the input voltage is approximately equal to the output voltage, the voltage comparator assists in preventing inrush current from flowing from the communicatively coupled system bus and prevents voltage sagging on the communicatively coupled system bus when another redundant power supply configuration is providing power to the communicatively coupled system bus.