Power Distribution Unit (PDU) Buying Guide

What is a Power Distribution Unit (PDU)?

A Power Distribution Unit (PDU) is a multiple outlet power strip designed to deliver conditioned power to mission-critical networking, server or telecom equipment. It is often used in conjunction with an Uninterruptible Power Supply (UPS).

Why are PDUs important and where are they typically used?

In a networking environment, devices need to be powered continuously, either from a whole site generator or rack-mounted UPS power source, and since many networking devices in use today are fitted with dual redundant power inputs, the total plug count can approach 80 or more—with many requiring two power sources to further mitigate the risk of power failure.

PDUs are commonly built for permanent placement inside rack enclosures, either in a zero rack space (0U) 4- to 6-foot vertical format, or horizontally in a one-to-two rack space (1U, 2U) form factor. Since a PDU generally functions as the entry point for power into a rack, most offer a 10- to 15-foot input cord option so that it can be connected to a distant power source, all the way from the top of a 7-foot rack enclosure if necessary. A PDU unit is meant to pass conditioned power that is sourced from a large centralized UPS or generator installation in large data center applications or from individual UPS systems in a smaller enterprise environment. Since high reliability is critical, features found on standard power strips and surge suppressors, such as power switches, line filtering and surge suppression are left out to eliminate any possibility that the power strip could interrupt the flow of electricity to critical networking gear.

When selecting a Power Distribution Unit (PDU), there are several questions that need to be answered.

Input Power

Do you need Single-Phase or 3-Phase input power?

If you use 3-Phase power, select a 3-Phase PDU. Otherwise, choose a Single-Phase PDU.


Type of Mount

How do you want to mount your PDU?

Some PDUs are designed to be mounted horizontally in a rack cabinet, some vertically, and some can be mounted either way.


Voltage

What is the voltage of your power source?

Select a PDU that has the same nominal voltage as your AC source and your equipment. In most cases, it won't be possible to connect the PDU if you select the wrong voltage; doing so may cause equipment and PDU damage. NOTE: Some 3-Phase PDUs have output voltage which is different from their input voltage. Consult a Tripp Lite specialist to make sure that you choose a PDU which meets your needs.


Input Plug

What type of input plug should the PDU have?

Be sure that the input plug matches the receptacles of your power source.


Receptacles

What type and how many receptacles should the PDU have?

Be sure that the PDU's receptacles match the plugs on the items you'll be connecting to it. Also be sure to select a PDU with at least as many outlets as the number of items you will be plugging into it.

Other Considerations:

Switched PDUs

Provide remote outlet control to eliminate costly service calls by allowing you to reboot locked devices.

Monitored PDUs

Provide remote monitoring/reporting to prevent overloads that cause damage.

Metered PDUs

Feature built-in load meters that display connected equipment load in amps to prevent overloads and safely optimize load levels.

Dual Circuit PDUs

Provide dual (completely separate) power circuits to accommodate multiple servers with redundant power supplies.

Auto-Transfer Switch PDUs

Include an integrated auto-transfer switch that provides redundant power sources to devices without redundant power supplies.

Hot-Swap PDUs

Feature a manual transfer switch that controls PDU output between utility and UPS power sources for UPS maintenance without interrupting power to connected equipment.

Find the perfect PDU for your specific application.

The best way to choose the right PDU is to visit our convenient online PDU Selector Guide. It will walk you step-by-step through the selection process.

Launch PDU Selector Guide