Rack PDUs take power from the rack's power source (branch circuits) and distribute it, as needed, to the various outlets on the PDU itself. In short, PDUs turn a single power input into multiple power outputs. There are two main categories of PDUs: basic PDUs and intelligent (networked) PDUs or iPDUs. The nuance comes as you consider variables such as PDU voltage, phases, plug and outlet. A power distribution unit, also known as PDU, refers to a device fitted with multiple outputs designed to control and distribute electric power, which is normally used in the racks of networking equipment located in a data center.