Some embodiments of the inventive subject matter provide a power distribution system for a data processing system. The power distribution system includes a plurality of uninterruptible power supply (UPS) units, respective ones of which are configured to be coupled to respective loads via respective load busses, at least one reserve bus, a switching circuit configured to selectively couple and decouple the UPS units and the load busses to and from the at least one reserve bus and a control circuit configured to control the switching circuit responsive to a state of the data processing system. The control circuit may be configured to cause the switching circuit to couple the first UPS unit to the at least one reserve bus concurrent with the first UPS unit being coupled to a first load via a first load bus.