What Is PDU In Networking?

1. The concept of PDU

2. The function of PDU

Some all-in-one PDUs currently include surge protection and high-temperature resistance modules. These can effectively absorb excessive current or voltage to prevent sudden peaks from damaging devices connected to the PDU. Additionally, their high-temperature resistance function helps prevent overheating that could ignite facilities in the server room.

Figure 2: Smart PDU

COBTEL's standard PDUs mainly come in two types: 10A in and 10A out, and 16A in and 10A out. These are commonly used in general projects. They feature simple structure, low failure rate, durability, and long service life.

Figure 3: 10A PDU

Figure 4: 16A PDU

3.  The structure of a standard PDU

A standard PDU consists of a plug, connecting cable, and socket strip. The plug's outer shell is made of ABS material, with 0.5mm phosphor bronze nickel-plated pins; the plug uses an integrated injection molding process; it is sturdy and stable, with no risk of pins falling out. The cable's outer skin is made of flame-retardant PVC. The inner copper core is pure copper, with an insulating shell made of PVC plastic, and a black outer skin made of flame-retardant PVC plastic. The socket strip is modularly designed, with new national standard sockets; the socket shell is made of flame-retardant PC plastic with a UL 94V1 flame retardant rating; the inner metal socket pieces are made of phosphor bronze with a thickness of 0.5mm. The backplate uses a pure copper process, with the connection points between the pure copper and the socket pieces using permanent solder connections. The PDU's outer shell is made of aluminum alloy material with a black coating. It is lightweight, simple, and has good heat dissipation performance. The indicator lights are detachable and replaceable.

Figure 5: PDU Features

4. Types of PDU:

Depending on the application environment and internal functional modules, PDUs come in various types; their application scenarios and prices also vary significantly.
First, different output currents and output powers; conventional PDUs are divided into 10A and 16A based on output current; a 10A PDU has a rated power of 2500W, with a cable copper wire of 1 square millimeter; a 16A PDU has a rated power of 4000W, with a cable copper wire of 1.5 square millimeters.
High-power, high-current PDUs can provide 32A/32A/65A and a rated power of over 4000W, meeting the needs of high-power industrial equipment, large servers, large storage devices, and bitcoin mining.
Second, different specifications; conventional PDUs typically have 8 modular sockets, with a height of 1U and a length of 19 inches; there are also customized PDUs, such as 2U, 19-inch 10-socket PDUs; 16-socket or even 24-socket PDUs, with heights ranging from 1 meter to 1.8 meters.
Third, different functions; whether they have a main control switch. In conventional PDUs, there are two types: those with a main control switch and those without. PDUs with a switch are more expensive than those without. Considering the actual application environment, once the PDU is installed and functioning normally, the main control switch is rarely used. Therefore, many PDUs now omit the main control switch.
PDUs with various intelligent functional modules. The most common type among these is the surge protection PDU. The main function of the surge protection PDU is to prevent direct or indirect lightning strikes on various devices connected to the PDU due to lightning or unstable power supply at the power source, which can cause overloading. Surge phenomena typically include high peak voltages, excessive currents, and high temperatures caused by surges. These include zinc oxide varistors to absorb peak voltages, ceramic gas discharge tubes to handle large currents, and high-temperature fuse protectors to prevent overheating.
All-in-one PDUs; in addition to surge protection, all-in-one PDUs also incorporate various intelligent modules based on the application environment's needs. Common additions include power meters and ammeters to count the power consumption of devices connected to the PDU and to monitor the working conditions of the devices in real-time, promptly detecting the working status of the devices. They also include communication modules such as Bluetooth and wireless reception modules, reflecting the data monitored by the PDU to the network administrator in real-time. Additionally, some all-in-one PDUs include waterproof modules that automatically alert network management engineers when the air humidity reaches a certain level to address potential water ingress.
Although COBTEL's standard PDUs do not include all these features, they can produce the described lightning protection and multifunctional PDUs.

Difference between PDU Power Sockets and Ordinary Sockets
For many people, especially those in the low-voltage industry, the most challenging thing to explain and understand is the difference between PDU power sockets and ordinary sockets. Especially when dealing with clients, if the client does not understand the difference between the two, they often question the rationality of the project design. If not explained clearly, the client may reject the use of PDU, leading to reduced security in the server room and potential safety hazards.

Figure 6: COBTEL Socket Strip

5. The main differences between PDU and ordinary sockets

The main differences between PDU and ordinary sockets are: First, their functions differ; ordinary sockets only have power supply, overload protection, and main control switch functions, while PDUs not only have these but can also include surge protection modules, intelligent monitoring devices, communication modules, etc., enabling PDUs to have functions such as lightning protection, voltage resistance, static electricity protection, and fire prevention. Second, their application environments differ; ordinary sockets are mainly used in homes or offices to provide power for household appliances, telephones, computers, etc. The environment is relatively mild, and they typically last only 2 to 3 years, with a socket plug-in and out count of about 4500-5000 times. Therefore, their materials generally use ordinary plastics, or even recycled materials. PDU power sockets, on the other hand, are used in environments such as weak current wells, telecommunication rooms, and even industrial environments, which are relatively harsh; they also need to ensure a service life of at least five years. Therefore, the outer shell of PDUs is generally made of metal materials and high-strength ABS plastics, with functions such as static electricity prevention and anti-fall; additionally, the socket of PDUs can be plugged in and out more than 10,000 times. This is also related to its service life and application environment. Third, their load powers differ; ordinary sockets can only provide a maximum current of 16A, generally 10A or 16A, with a rated power of 2500W or 4000W. PDUs can not only provide 10A and 16A currents, with rated powers of 2500W and 4000W, but also provide currents of 16A/32A/65A and power configurations of over 4000W to meet the needs of different devices.

6. Important tips and reminders for using PDU outlets

Of course, high power and high current also mean higher risks. Therefore, when using PDUs, there are four things to avoid. First, avoid touching the PDU's sockets or connecting plugs with wet hands; second, do not use PDU sockets in wet, damp, or humid environments; third, keep PDU power sockets away from heat sources like radiators, heaters, amplifiers, stoves, and other heat-generating items; fourth, do not attach or wrap metal objects or any conductive materials around the PDU power socket's power cord.

Figure 7: PDUUSAGE GUIDELINES Prioritize Safety and Ensure Reliable Operation