PDU vs. Power Strip vs. UPS: Understanding Power Distribution Units

Posted by Thane Moore on January 18, 2022

When installing servers, storage arrays, network switches, and other gear, you need a reliable source of electricity. Power distribution units (PDUs), power strips, and uninterruptible power supplies (UPSs) can all be used in the data center to perform this function. Understanding their differences can help you choose the right tool for the job.

Comparing PDUs vs. Power Strips

Power distribution units (PDUs) look like oversized power strips — they have multiple outlets for plugging in IT equipment in the data center. However, PDUs differ from power strips in several ways.

Number and Type of Outlets

A power strip can have anywhere from two outlets to 20 or more. Most have “standard” NEMA 5-15R outlets, but they may also have other types.

PDUs that mount horizontally in a rack or cabinet typically have eight to 16 outlets, while those that mount vertically could have 40 or more. PDUs usually offer a variety of outlets to support different types of IT equipment.

Power Capacity

Most power strips have a rated capacity of 15 to 20 amps. PDUs can support higher amperages and have built-in circuit breakers to protect the branch circuit wiring.

Power Cord Length

Power strip power cords vary in length from a foot or less to 25 feet or more. UL requirements limit PDU power cords to 15 feet because of the heavier load supported by these units.

Mounting Options

Some power strips have tabs for mounting to the wall or a server rack, but the majority are meant to just lie on the ground or a shelf. Rackmount PDUs are designed to attach to a rack or cabinet, either horizontally like IT equipment or vertically in the back of the rack.

Surge Protection

Some power strips provide surge protection to reduce the risk that a voltage spike will damage electronic equipment. Do PDUs have surge protection? Generally, PDUs do not offer surge protection. However, they do provide overload protection and the ability to distribute power efficiently. Data centers generally require separate surge arresters to protect sensitive IT equipment from lightning strikes and power surges.

Other PDU Features

There are basic PDUs that do little more than provide a centralized source of power. However, network-enabled PDUs offer advanced features.

  • Switching functionality makes it possible to turn PDU outlets on and off remotely, enabling administrators to power cycle equipment.
  • Metering capabilities provide the data needed to make more informed decisions about energy management. Some intelligent PDUs also measure environmental factors that could affect the operation of IT equipment.
  • Alerting features in metered PDUs can notify IT staff when a circuit approaches maximum capacity, or some other threshold is reached.

Comparing PDUs vs. UPSs

PDUs and power strips perform similar functions and look somewhat alike, but PDUs and UPSs are very different. PDUs merely distribute power. They do not generate it. UPSs are essentially backup batteries in the server rack. They provide backup power in the event of an outage and complete protection against power quality problems. UPSs have multiple outlets, but these should be reserved for the most critical equipment in the rack. You can plug a PDU into a UPS as long as the UPS has sufficient backup power to support the load.

High-Quality PDUs from Enconnex

A data center is likely to use PDUs, power strips, and UPSs for various functions. However, PDUs arguably play the most critical role in day-to-day power management. Selecting the right PDU unit requires an analysis of the power requirements of your equipment and whether remote switching, metering, and alerting functionality would benefit your operations.

Enconnex offers a full line of basic, switched, metered, and universal PDUs in a wide range of configurations. Our PDUs are used in the world’s largest hyperscale and enterprise data centers, chosen for their quality, reliability, and cost-efficiency. Our team is here to help you select the right PDU to meet your demanding requirements. Just get in touch.

Posted by Thane Moore on January 18, 2022

Thane Moore is the Senior Director of Sales Operations & Logistics for Enconnex and has 20 years of experience in the IT infrastructure manufacturing space working for companies such as Emerson and Vertiv.

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