KNOWLEDGE CENTRE / POWER / RACKS

What Is a PDU and Why Do You Need One?

A power distribution unit provides a structured way to distribute electrical power to equipment in a rack.

A PDU is part of the physical power infrastructure in a rack. It distributes power from an upstream supply to connected equipment.

UPS sizing has two separate questions
UPS sizing has two separate questions Capacity determines whether the UPS can support the load. Runtime determines how long the batteries can support it. Utility powerIncoming ACUPSCapacity and topologyServersCritical loadSwitchesNetwork loadStorageData loadRuntimeBattery plus load

Capacity determines whether the UPS can support the load. Runtime determines how long the batteries can support it.

What does a PDU do?

A rack PDU provides multiple power outlets in a form designed for equipment installations. It can make rack power connections more organised and accessible.

PDU vs UPS

A PDU distributes power. A UPS provides backup power and power protection. They perform different roles and are often used together.

Consider the rack layout

The PDU should be positioned so that power cables can reach the equipment without creating unnecessary cable congestion. The available outlet types and cable lengths should be considered.

Check electrical compatibility

Voltage, current, plug and outlet types all need to match the installation. The PDU rating must be suitable for the connected load and upstream supply.

  • Input connection
  • Outlet type and quantity
  • Voltage compatibility
  • Current rating
  • Rack mounting arrangement
  • Cable routing
  • Total connected load
A PDU does not replace a UPS.

In a typical protected rack, the UPS provides the backup power while the PDU provides a practical way to distribute that power to the equipment.

Return to UPS

How to use this information

Confirm the exact product specification, supported configuration and compatibility before ordering. Platform generation, firmware, licences and optional components can change what a product supports.