Power Distribution Units:
A Power Distribution Unit (PDU) is a device with multiple outlets designed to distribute electric power to computers or networking equipment within a rack.
As the number of rack-mounted servers, blade servers, network switches and routers has increased, so has the need for power in the rack. For example, a blade server installation consisting of four 7U blade server frames in a 42U rack would require sixteen 20A power supplies. PDUs solve this problem by taking the power supplied to the rack and distributing it via multiple outlets to the rack's servers and networking equipment.