PDU (power distribution unit)
Beginner
A big power strip that shares electricity out to the racks and the computers inside them.
Novice
The equipment that splits the UPS output into circuits for each rack, often with breakers and meters. Floor-standing PDUs may include a step-down transformer; rack PDUs are the power strips inside the rack.
Expert
Losses are mostly in any internal transformer and in cabling; PDU output is one of the standard points for measuring PUE’s IT energy. In ORv3-style racks the rack PDU is replaced by power shelves feeding a DC busbar.