Power Distribution Units (PDU) in the Data Center

PDU, or Power Distribution Unit, is a device used in data centers and other computing environments for distributing electrical power to the various components of the network. PDUs can range from simple and inexpensive rack-mounted power strips to larger, more sophisticated units with power conditioning, power monitoring, and remote management features.

Here are some main points to consider when implementing PDUs in your data center:

  1. Capacity: It’s crucial to know the power needs of your data center and to ensure that the PDU can handle those needs. If you’re running high-density racks, you need PDUs that can handle the load.
  2. 2. Features: There are many features that you might want in a PDU. Some offer remote management, allowing you to control power to individual outlets, which can be useful when you need to reboot a device remotely. Other features to consider include power metering, environmental monitoring, and redundant power supply.
  3. 3. Form Factor: PDUs come in a variety of form factors, including rack-mounted, cabinet, and standalone. The right choice depends on your data center’s layout and needs.
  4. Outlet types: The type of outlets on the PDU should match the power cords of your devices. Depending on the country and standards used, you might need a variety of outlet types.


AC vs DC

AC, or Alternating Current, is the type of electricity that you would typically get from a utility company. It is used because it can be transmitted over long distances without much loss.

DC, or Direct Current, is the type of power that most electronics use internally. While it is more efficient to use in data centers, the technology to convert AC to DC has improved, making AC power distribution still the most common method used.

As for which is typically used, most data centers use AC PDUs, but some high-efficiency data centers are moving towards using DC PDUs because they are more efficient and result in less energy loss.

Best practices and recommendations for PDU implementation in a data center:

  1. Proper Planning: Carefully calculate the power requirements of your data center and plan accordingly. Don’t forget to account for future growth.
  2. Redundancy: In critical applications, consider using dual power supplies for devices and PDUs. This provides a fail-safe in case one power supply fails.
  3. Use Intelligent PDUs: These devices provide information about power consumption, which can help with capacity planning and identifying problems.
  4. Proper Load Balancing: Balance the power load between phases in a three-phase system to prevent overloading one phase, which can cause an unexpected shutdown.
  5. Environmental Monitoring: Some PDUs come with environmental monitoring capabilities. This can be useful to monitor conditions such as temperature and humidity in the data center.

Remember, when dealing with PDUs and data center power infrastructure, it’s often wise to consult with experts in the field. They can help you understand your unique needs and ensure that your data center is both efficient and reliable.



Electricity is typically distributed from the power grid in a three-phase format. This means that there are three alternating currents (AC) within the same power line, each with the same frequency and amplitude but with different phase angles.

A three-phase power system involves three wire conductors that carry three alternating currents, which reach their instantaneous peak values at different times. Instead of one wave peaking and then dropping off, with three-phase power, another wave is reaching its peak just as the previous one is diminishing.

The three phases are typically represented as a Y or Δ configuration (also known as wye and delta respectively), with each representing a different phase. There is typically a fourth neutral wire. When the system is balanced, which means the load is evenly distributed across the three phases, the sum of the currents in the three phases, and the neutral should theoretically be zero.

Here are a few advantages of a three-phase system:

  1. More Efficient: Three-phase power systems are more economical and efficient than single-phase systems. They can transmit more power using less conductor material and provide a constant power flow.
  2. Better for High Power Loads: Three-phase systems are better for running heavy electrical equipment and high power loads as they create a smoother, more balanced power supply.
  3. Reduction of Power Flicker: In single-phase systems, power can drop to zero after each cycle. In three-phase systems, the power never drops to zero, which can result in less flicker in lighting and less vibration in motors.

In a data center, three-phase power is often used because it’s more efficient and suitable for high power density environments. When installing PDUs in a data center, it’s essential to balance the power load across all three phases. Load imbalance can lead to inefficiencies and can potentially overload one or more of the phases, causing equipment failure and power outages.