Your Guide to Choosing the Right Power Distribution Unit (PDU)

Ranging in size and complexity, power distribution units (PDUs) give data center managers more control over electrical power. Some PDUs are simply power strips, while others are complex with surge protectors. Choosing the right PDUs for your data center’s immediate power management needs and anticipated future demand can be a challenge. Facility managers must carefully consider input and output factors, how the equipment will be mounted, additional features, and the overall budget.

That’s why we put together this guide to help you choose the right power distribution units for your server racks.

1. PDU Mounting

First, focus on the structural element. Do you need the PDU to be horizontally mounted or vertically mounted? Horizontally mounted PDUs take up one to two rack spaces and can be mounted anywhere in a rack enclosure while remaining plugged into a power source via a long 10- or 15-foot cord. For even more versatility, you can horizontally mount PDUs to the underside of a counter or directly to a wall.

Vertically mounted PDUs occupy zero rack spaces because they attach to the vertical rails of the rack. Most vertically mounted PDUs offer button mounting, where users slide the PDU’s mounting buttons into the mounting holes of the rack. This installation process is significantly faster and easier than mounting with screws.

2. PDU Input Phase

Once you’ve determined whether your PDU needs to be vertical or horizontal, determine its input voltage, including its amperage and the number of phases. This information influences the PDU’s plug type. 

If you already have a powered rack, you can simply examine the receptacle where you will plug in the PDU to determine the right PDU input. 

Consider these factors to determine your needed PDU input phase:

  • Building power: Ask your facility manager or an electrician whether the building’s power is single-phase or three-phase. Most offices will have either 120V or 208V single-phase power.
  • Application density: For a low-density rack of 1U or 2U servers, you can use a single-phase PDU. But for larger commercial racks, you may need three-phase power capabilities. If it’s available, three-phase power is more cost-effective and efficient.

3. PDU Input and Output

Next, carefully consider connectivity—both the input plug and the output receptacle. The input should connect to a generator-supported power source or a UPS system. Usually, PDUs have a detachable power cord and are rated for international use, so the user just attaches their local plug to the input. To choose the correct output receptacle, make sure the power cords match the equipment’s voltage level. 

4. Select the Right PDU

Every data center has unique needs, so it’s crucial to set goals before the PDU selection process. For example, if you have a large data center with hundreds of server racks, your primary goals may be to save physical space and reduce costs. Large facilities need to be monitored for power consumption at multiple levels, so you may not find as much value in monitoring the PDUs. In these cases, basic or metered PDUs may be most helpful.

On the other hand, branch locations not staffed by onsite personnel benefit more from switched PDUs. Although these solutions are more expensive up front, they provide long-term cost savings because they eliminate the need to send IT staff to manually switch the power on and off.

Find the Right PDU With Captor Corporation

Whether your facility needs basic power distribution units, intelligent power distribution units for high-tech operations, or a large volume of power distribution units for multiple locations, Captor Corporation is here to help. We produce 100% made-in-the-USA versatile electronic and electrical equipment for commercial, industrial, and military applications. Our company is ITAR-registered and certified per ISO 9001:2015 and AS9100D.

Contact us today for help choosing the right PDU or to learn more about our capabilities.

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