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A Cheat Sheet for Buying Your Next PDU

If your organization is growing, so are your technology requirements. At some point, you’ll need more electrical outlets than you have. Power strips may be enough for home offices, but anyone with plans for growth should understand the benefits of using a PDU.

This guide will review the basics of power distribution for business environments to help you make a confident and informed buying decision.

First things first. What is a PDU?

A power distribution unit (PDU) distributes reliable network power to multiple devices. It does not generate or condition power, but delivers AC power from an uninterruptible power supply (UPS), a generator, or utility power source to servers, networking hardware, telecom equipment, and other devices.

What does a PDU do?

In its most basic form, a PDU does the same job as a power strip. It uses current from a single source, usually a wall outlet, to power multiple devices, such as computers, peripherals, and networking gear. PDUs are designed for installation in equipment racks, keeping power within reach of rack mounted devices such as servers, switches, routers, or cooling fans.

PDUs are most often used in data centers, network closets, VoIP phone systems, and industrial environments.

Does it do anything else?

Beyond standard power distribution, PDUs are for in-depth power management and monitoring. Below are eight of the most common PDU types available on the market.

  • Basic
  • Metered
  • Monitored
  • Switched
  • Switched Metered-by-Outlet
  • Metered Auto Transfer Switch (ATS)
  • Switched Auto Transfer Switch (ATS)
  • Maintenance Bypass

Do PDUs provide surge protection?

Rack surge protectors distribute power from a single source to multiple devices but are not strictly PDUs. They are designed for use with equipment that needs to be guarded against voltage spikes and surges but does not require battery backup. Because the primary feature of these units is protection against over voltages, they are considered surge protectors and not PDUs.

Which type of PDU is right for me?

To find the right model for your needs, ask yourself the following six questions.

1. Where will I install it?
2. What kind of input power do I have?
3. How much power does my equipment need?
4. How many outlets do my devices need?
5. What kinds of plugs do my devices have?
6. Do I need other features?

1. Where will I install it?

PDU models are typically available in 1U or 2U heights for horizontal mounting. They can also be mounted vertically, known as 0U. Depending on the model, they can be mounted in a rack enclosure, on a wall, or under a shelf.

Horizontal PDUs are designed for mounting in EIA-310 standard 19-inch equipment racks. They can be placed above, below, or between the components they power.

Vertical PDUs look like tall power strips. They fit on the upright rails of a rack enclosure and do not take horizontal mounting space away from other equipment.

2. What kind of input power do I have?

Depending on your location and building type, you may have either single-phase or three-phase power. If you’re not completely sure, ask a licensed electrician. Here’s the difference:

Single-phase power alternates between positive and negative voltage; in the United States, the rate is 60 cycles per second. That means the wave has zero voltage every time it moves from positive to negative and back. Most household and office power are single-phase and work with the following receptacle (outlet) types:

Three-phase power eliminates these moments of zero voltage by offsetting three simultaneous waves. When one wave reaches zero voltage, the other two are at positive and negative points in the cycle. Three-phase power is common in commercial and industrial environments.

Most offices have single-phase power—but make sure you know before buying any new equipment.

3. How much power does my equipment need?

The amount of power consumed by each device should be listed in volts and amperes (VA) or in watts (W) in the user manual or on the equipment itself. Add up the total consumption for your equipment and write it down. Your power source—utility power from a service panel, local power from a generator, or backup power from a UPS—should be higher than that.

Note: Many devices use automatic switching power supplies that can be used with voltages from 120 to 240. If your power source is 120V (typical for North America), base your calculations on that figure. If it’s 200V/230V (typical for Europe and Asia), use the higher number. For input amperage, use the figure listed on the device or in its user manual.

One PDU connected to one UPS can provide conditioned power to a smaller network. Larger and more complex installations may need multiple PDUs and a large-capacity UPS system.

4. How many outlets do my devices need?

This question is probably the easiest to answer, but take it seriously. The PDU you choose should have at least as many outlets as the number of plugs you need to connect. If a device has more than one plug, or if one device has to be plugged into another, adjust your count. And remember to leave room for more devices, such as lights or cooling fans.

5. What kinds of plugs do my devices have?

Each PDU can support several devices. The plug shape corresponds to the required voltage and amperage. CyberPower offers PDU models to fit the following plug types:

6. Do I need other features?

A basic PDU shares a single power source with multiple devices. It simplifies the management of rack equipment and makes a valuable addition to any IT installation. Advanced models do much more, from measuring demand to protecting against downtime to allowing remote control through software.

1. A Basic PDU distributes unfiltered AC power from a UPS system, generator, or utility source to multiple connected devices.

2. A Metered PDU distributes network-grade power and meters load in amps to prevent overloads and help users optimize load levels.

3. A Monitored PDU distributes network-grade power and helps users prevent downtime due to overloads or other power events. It supports local management with a digital meter display and remote monitoring through an SNMP network interface.

4. A Switched PDU distributes network-grade power and allows users to control outlets individually or collectively. A digital meter provides information on load and voltage and supports local control; an SNMP connection enables remote monitoring and control.

5. A Switched Metered-by-Outlet PDU combines network-grade power distribution with local and remote outlet-level monitoring and control. It allows remote switching for unscheduled reboots, automated load shedding, controlled power cycling, and more. Power event notifications by email or SMS text help users mitigate risk.

6. A Metered Auto Transfer Switch (ATS) PDU receives unfiltered pass-through power from redundant plugs connected to separate power sources and distributes it to single-corded connected equipment. An LCD screen displays amperage, input and output voltage, active consumption in kilowatts, and hardware and firmware information. An optional SNMP card allows remote monitoring and management.


7. A Switched Auto Transfer Switch (ATS) PDU has all the features of a switched PDU, plus the ability to connect separate power sources to single-corded connected equipment for redundancy. An LCD screen can display amperage, input and output voltages, active power consumption in kilowatts, and information about hardware and firmware versions. A standard SNMP card allows remote monitoring and management over a network connection.

8. A Maintenance Bypass PDU helps prevent downtime. It allows the seamless transfer of an electrical load from UPS power to utility power for continuous operation of connected equipment when performing maintenance, replacing batteries, or installing a new UPS.

Take the next step

Use our PDU product finder to compare features and review detailed specifications side by side. And if more questions come up, don’t worry; just contact our power distribution experts.

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Interop ITX Conference

The Interop ITX Conference offers five days of world-class education, compelling speakers, and unlimited networking opportunities to help technology leaders keep up with the challenges and drive their businesses forward.

Join CyberPower May 15-19, 2017 at the MGM Grand in Las Vegas, NV at booth #232 as we help give attendees strategic insight, hands-on technical resources and an inside look at the emerging technologies and equipment affecting today’s IT organizations.

Learn more about Interop ITX 2017 and get a 15% discount on your registration.

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2017 ADTRAN Broadband and Business Solutions Summit

At the 2017 ADTRAN Broadband and Business Solutions Summit, service providers, utilities, municipalities, consulting and engineering firms seek the latest technology information for developing networks and services to meet market demands for today and the future. ADTRAN is an established supplier of advanced network infrastructure and converged communications solutions. Join CyberPower from April 10 – 12, 2017 at the 2017 ADTRAN Broadband and Business Solutions Summit event for educational opportunities, industry forums and how CyberPower can help service providers power and protect their broadband and communications networks.

Visit ADTRAN’s website for more information.

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CyberPower Introduces New Metered-by-Outlet Power Distribution Units

Advanced PDU models feature measurement and control of individual outlets to maximize utilization and device management. Designed for use in data center, co-location, and environments with accurate power monitoring requirements, these new models allow active metering of individual outlets. This Metered-By-Outlet (MBO) capability provides detailed information on power consumption.

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CyberPower Releases Updates to Business Class Power Management Software

CyberPower has updated its PowerPanel® Business Edition (PPBE) software to version 3.2. It provides advanced power management for uninterruptible power supply (UPS) systems and network connected power distribution units (PDU). With this release, the new features make PowerPanel Business Edition even more helpful for power users. PPBE Agent now has SNMP support, allowing users to monitor USB or serial port connected UPS systems via SNMP, and to receive SNMP trap notifications. PPBE Client can now manage redundant power configurations, monitoring the status of separate CyberPower UPS systems simultaneously.

Read the full press release.

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CyberPower Earns Silver in the ChannelPro-SMB 2016 Readers’ Choice Awards

ChannelPro readers again honor CyberPower as a leader for power protection in the Best UPS and Power Conditioning Vendor category in the annual readers’ choice awards. The annual awards highlight the vendors, distributors, and professional organizations whose solutions, services or programs best fit the requirements of SMBs and the channel pros who serve them.

Read the full press release.

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CyberPower Launches Channel Partner Alliance

The Channel Partner Alliance program is designed to maximize partner profitability and create new sales opportunities for resellers to help power their businesses. The program offers exclusive partner discounts, one-hour response times to sales inquiries, training and an incentive program that rewards sales representatives for selling CyberPower.

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Computer Talk Radio with Benjamin Rockwell

Computer Talk Radio discusses power protection and CyberPower (At 57:30 of the show) with Marty Winston, tech trend watch and editor of Newstips Bulletin. Marty discusses the benefits of power protection and the brands to watch. Computer Talk Radio is a nationally syndicated broadcast radio program on computers, technology, and your life. Benjamin Rockwell, the show host and a computer nerd, leads the team as the expert guide through the technical jungle of jargon, and the valleys of viruses, to reach the pinnacle of power of your computer problems.

Listen to the show.

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Silver Bullets and Surge Protectors

Vampire Power

An Invisible Villain

If you’re like most people, you have an invisible villain hiding in your television set, slowly sucking away your electricity and your money. This silent monster is called standby power, also known as vampire power. But you can get rid of it.

Vampire Power

Television sets and electronic devices often include a standby power feature. They draw a small amount of electric current even when they are switched off, so that they can be fully powered up and ready to use sooner when you turn them on. That small amount adds up, especially when you have multiple devices.

Chargers can also be vampires. A small transformer that converts AC utility power to DC to recharge a mobile phone, tablet, media player, or other small device will keep drawing power even if the device is fully charged or no longer connected.

In fact, according to a 2015 study conducted by the Natural Resources Defense Council, idle load electricity accounts for nearly one-fourth of electric power consumption in the United States—enough to keep 50 major power plants running all year. That’s a considerable amount to pay just for electronics to start up a little faster.

Wooden Stakes and Garlic

To get rid of the power vampires in your house and office, you don’t need holy water or sunlight—just a few changes to your daily habits and maybe a few devices. Here are some proven tactics for reducing idle loads and unnecessary costs:

Measure your electric power consumption. You can find a smart meter at any home improvement store, and use it to find out how much electricity your devices really use. This will also help you decide where to concentrate your efforts.

Use a surge protector or power strip with energy saving technology. These let you turn off power to connected devices without having to unplug them. Some surge protectors have smart outlets that switch off power automatically when a “master” outlet is no longer in use.

Use a timer for devices you only use at certain hours. For example, if you only use your coffee maker in the morning, put it on a timer that switches it off for the rest of the time. Your computer operating system probably has energy saving settings built in, too.

Change the settings on your home entertainment devices. Your television, gaming console, digital video recorder, streaming device, or cable box may let you switch off its quick-start feature.

Unplug electronics that aren’t in use. If you’re not going to use a device for a while, pull the plug. This keeps it from drawing power while it’s not doing anything for you.

Save and shut down instead of using sleep mode. Computers and gaming consoles will generally let you pick up where you left off if you save your current status. You wouldn’t leave your car running for hours while you’re not using it; park it and switch it off.

Check ENERGY STAR ratings when you buy. Many electronic devices have an ENERGY STAR energy efficiency rating, showing how much electricity it consumes, and how that compares to similar products. The differences can be significant.

A New Dawn

Power utility companies understand the importance of energy conservation, and would rather help you reduce waste than build more power generation facilities. For that matter, some government agencies have proposed rules that limit how much electricity a device can draw while it’s in standby mode. But you bear the cost, so you have the most to gain. A few simple changes to your equipment and routine can make a big difference in how much you spend.

If you have more questions or a story to tell about vampire power, write to us at And please tell us whether you think this post is useful or entertaining. Thanks!