Why would I need two PDUs in one server rack?

Using two power distribution units can provide additional power resilience, especially for servers that are fitted with dual power supplies. One PDU connects to the ‘A’ power supply and the other to the ‘B’ supply, and ideally, each of these is fed from a separate (protected) power source. If one supply fails, the other can continue supporting the equipment, as long as it has the capacity to.