What is a Power Distribution Unit (PDU)?
A Power Distribution Unit is an electrical device with multiple outlets designed to distribute power to computing or networking devices in a rack. PDUs come in a variety of styles that provide everything from basic power distribution to enhanced remote power management.
How to Choose a PDU for Your Network or Data Center
Top three factors to consider in your buying decision.
Horizontal vs. Vertical Installation
Horizontal PDUs can be mounted inside the rack, which will take up one or two rack spaces (1U-2U). Vertical PDUs can be mounted on the back or side of the enclosure without taking up any RU space. Horizontal PDUs are smaller than Vertical PDUs and have fewer outlets.
Voltage of Your Connected Equipment
After adding up the total power consumption of all your rack mount equipment, that total should be lower than what your power source the power demand to avoid overloading.
Outlet Types
You should select the PDU models with suitable output receptacles for the connected devices, and the number of PDU’s outlets should exceed the number of plugs you need for further expansion.
Types of PDUs Available
Basic Rack PDUs
A Basic PDU (power distribution unit) is a device for providing reliable AC power distribution to multiple devices in a data center environment, or anywhere power is needed. See FS' selection of Basic Rack PDUs.
Metered Rack PDUs
Metered Rack PDUs are the perfect solution to monitor outlet level and critical power quality factors. They can help IT managers balance loads and prevent overloads. See FS' selection of Metered Rack PDUs.
Monitored Rack PDUs
Monitored Rack PDUs include the features of Metered Rack PDUs, except that, Monitored Rack PDUs have a network interface to support remote monitoring or management. See FS' selection of Monitored Rack PDUs.
Switched Rack PDUs
Switched Rack PDUs have all Monitored Rack PDUs features, plus local or remote control of individual outlets. They can help IT administrators to remotely reboot malfunctioning devices and turn power off and on to each outlet. See FS' selection of Switched Rack PDUs.
Basic Rack PDUs
A Basic PDU (power distribution unit) is a device for providing reliable AC power distribution to multiple devices in a data center environment, or anywhere power is needed. See FS' selection of Basic Rack PDUs.
Metered Rack PDUs
Metered Rack PDUs are the perfect solution to monitor outlet level and critical power quality factors. They can help IT managers balance loads and prevent overloads. See FS' selection of Metered Rack PDUs.
Monitored Rack PDUs
Monitored Rack PDUs include the features of Metered Rack PDUs, except that, Monitored Rack PDUs have a network interface to support remote monitoring or management. See FS' selection of Monitored Rack PDUs.
Switched Rack PDUs
Switched Rack PDUs have all Monitored Rack PDUs features, plus local or remote control of individual outlets. They can help IT administrators to remotely reboot malfunctioning devices and turn power off and on to each outlet. See FS' selection of Switched Rack PDUs.
What Type of PDU Do You Need?
The chart below will give a clear illustration that may help you identify these common PDU types.
- FeaturesBasic Rack PDUsMetered Rack PDUsMonitored Rack PDUsSwitched Rack PDUsSwitched Metered-by-Outlet
- Power Distribution
Monitoring
- Total voltage of each phase
- Total operating voltage of each phase
- Serial port communication address
- Device IP
- Total load power of each phase
- Total energy measurement of each phase
- Temperature/humidity status
- Serial port baud rate
- Individual outlet load current
- Individual outlet load power
- Individual outlet power metering
Controling
- On/off control of each output unit
One-key switch control
Each output unit up and down power on/off interval delay time setting
Total output unit unified sequential on/off interval delay time setting
Each phase total/individual power metering zero
Custom alarms
- Total operating voltage of the phase exceeds its threshold setpoint
Total load current of the phase exceeds its threshold setting
The temperature/humidity exceeds its threshold setting - The load current of each output unit exceeds its threshold setpoint
Multiple alerting methods
- The buzzer beeps
- The alarm indicator flashes
- The software interface has an alarm prompt to check the working status, and the font color changes to red, which generates an alarm log record
- Alarm prompts displayed in red font on the LCD screen
- Automatically send e-mail to system administrators
- SNMP sends Trap alarm status information
Access method
- Access control through IE
- Telnet，monitored via the network command line
- MODBUS，Communication protocol console
- SNMP（V1/V2c/V3），Manage workstation access control through a standard network
Key Features
Reduce Energy Costs
Using PDU means running various outputs all from the same source. Thus, it's much easier to channel energy and avoid any unnecessary waste.
Provide Reliability for Power Loads
PDUs can help to link each socket to a computing or networking device so as to multiple integrated power outputs. Adopting a PDU solution will help to protect against data loss and downtime caused by a disconnected plug.
Create an Organized Structure
The optimal form factor takes up less space for efficient rack space utilization. Furthermore, the mass situation of hundred different wires running around leading to different places won't exist any longer.
Offer Convenient and Flexible Installation
The rack PDUs are generally lightweight to mount and are available in either vertical or horizontal formats. Most of them are versatile and cost-effective to meet various network requirements.
Frequently Asked Questions
Q: What is the difference between a UPS and a PDU?
A: UPSs provide battery backup in the event of an outage, and they can also filter incoming power and provide surge protection. PDUs does not generate or condition power on its own, they merely distribute power.
Q: What is the difference between a PDU and a rack-mount power strip or surge protector?
A: PDUs, power strips and surge protectors all provide multiple outlets, but only PDUs can provide robust distribution of reliable network power for multiple servers, networking hardware, telecom equipment and other IT devices.
Q: What is the difference between a power distribution unit and a power distribution center or cabinet?
A: Power distribution cabinets are electrical equipment, they can provide and redistribute electrical energy, protect electrical power lines, overload and short circuit currents.
Q: How do you use a hot-swap PDU?
A: The primary input plugs into an online UPS system.
The secondary input plugs into a wall outlet.
If the UPS system is taken offline for maintenance, repair or replacement, the PDU keeps the load powered by automatically switching from the primary input to the secondary input. When the UPS system is restored, the PDU will switch back to the primary input. If the ammeter is damaged, the PDU can be removed directly without interruption.Q: How does a PDU help monitor conditions in the rack, network closet or data center?
A: The network interface of monitored or switched PDU can receive information communicated from environmental sensors connected to the PDU, which can help ensure optimum operating conditions. The sensors monitor ambient temperature and humidity, as well as contact closure status of alarm, security and telecom products.