Reliable power is essential in current IT environments like network closets and server rooms, and data centres. The PDU and UPS systems are two devices that are frequently used for this purpose. Although these systems are considered to be complementary devices, they have very different functions.
This guide describes how each PDU and UPS operates, the differences between the two, and which device you should use for your specific requirements.
What Is a Power Distribution Unit PDU?
Power Distribution Units distribute electrical power to multiple devices from one main source within a server rack. They can be installed in racks with servers, switches, and storage devices for the purpose of providing power.
The main responsibilities of a PDU are:
- To provide electricity to other devices
- To manage the electrical load
- To offer an optional surge protection feature
- To monitor the usage of the power distribution unit
What is a UPS?
An Uninterruptible Power Supply protects a device against power interruptions. It uses a battery to supply temporary backup power in the event of a power outage or when there is an excessive or insufficient amount of electrical power.
There are different types of UPS solutions:
- A line interactive UPS, designed for small to medium-sized environments, has voltage regulation capabilities.
- Double conversion UPS, which provides the highest level of electric power protection for mission-critical applications and systems.
- In an environment experiencing numerous electrical interruptions, the inline-interactive UPS is best used because it provides not only a battery backup but also voltage regulation.
PDU vs UPS: The Major Differences
Below are key differences between an Uninterruptible Power Supply and a PDU, which show how each provides reliability to ensure that electrical equipment remains operational at all times.
Usage and Functionality
The Primary Function of a smart PDU is to deliver electrical power to multiple devices from one central location. A Uninterruptible Power Supply, on the other hand, provides back-up support during power outages and maintains equipment from damaging power quality issues.
Power Backup Ability
A PDU does not have any storage capacity and therefore cannot supply power to any connected devices when utility power is off. However, a UPS solution is capable of supplying immediate backup power whenever normal utility power is lost.
Power Quality and Protection
The Power Distribution Units have some of the basic surge protection functions built into them, but they don’t provide the power conditioning capabilities that Uninterruptible Power Supply Systems do, such as filtering out the electrical noise in circuit delivery and providing the voltage regulation needed for sensitive equipment.
Installation and Placement
PDUs are generally used as rack-mounted power distribution in a server rack, while a UPS System is generally installed upstream, supplying the clean, stable power to multiple PDUs and then distributed throughout the entire server rack via the power distribution unit.
FAQs
- Can a PDU be used with a UPS?
Yes, this is recommended for server environments. UPS provides backup power for IT equipment, whereas a PDU distributes it effectively. - Which is better, UPS or a power station?
When it comes to IT and server environments, using an Uninterruptible Power Supply is the best way to go due to its benefits of fast transfer time. It provides power conditioning and integration capabilities with IT systems. These features are lacking in power stations. - What does a PDU do?
The purpose of a PDU is to provide an orderly and safe manner for distributing protected electricity from a single source to many devices, particularly in server racks, while giving the ability to monitor and control the power provided.