PoE Standards and Specifications

The original IEEE 802.3af-2003 PoE standard provides up to 15.4 W of DC power on each port. The updated IEEE 802.3at-2009 PoE standard, also known as PoE+ or PoE plus, allows for up to 30 W of power to Type 2 devices. That’s sufficient power for devices such as VoIP phones, wireless access points, and security cameras. But it’s not enough for technology like flat screen displays, LED lighting, or retail POS terminals.

Introducing the 802.3bt PoE Standard

To meet the demand for higher power, the IEEE released a new PoE standard at the end of 2018, to significantly increase capacity. IEEE 802.3bt allows for up to 60 W to 100 W of power at the source by providing power over four pairs of wires (compared to the previous technology’s ability to power over just two pairs). This increase in power allows you to use PoE for a greater range devices and applications. As an added benefit, the new standard will boost energy efficiency by minimizing power loss in the cable, potentially cutting power loss in half.

The new standard will include support for 2.5GBASE-T, 5GBASE-T and 10GBASE-T, while existing standards have a maximum speed of 1-Gbps. This new support will create intermediate data speeds between existing standards.

PoE Types and Power Levels

Previous PoE technology included PoE Type 1, also called IEEE 802.3af, and PoE Type 2, better known as 802.3at or PoE+. Both utilize 2-pair Power over Ethernet, Type 1 with a maximum of 15.4 W per port and Type 2 with a maximum of 30 W per port.

With the new 802.3bt standard come two new options: Type 3 and Type 4. Type 3 is also called 4-pair PoE, 4PPoE, PoE++, or UPoE. It provides 60 W of power per port and is ideal for video conferencing equipment, multi-radio wireless access points, PTZ cameras, and building management devices.

Type 4 (another designation is high-power PoE) offers the highest power capabilities, potentially up to 100 W of DC power (71.3 W to each device), and can support flat screens and laptops. For more detailed specifications on PoE Type 4 and other types, you can refer to the following table.

Cables Considerations

PoE switches and injectors are based on the rules defined by the IEEE 802.3 working group. As such, no special cabling is required. Keep in mind, though, that Ultra-PoE connections require 8-pin network cabling. Almost all networking cabling is 8-pin, but there is inexpensive cable out there that may only come with 4-pins. As those can only be used for Fast-Ethernet connections, they have become increasingly rare.

There’s a lot of (mis)information out there about the drawbacks of this cable type. Copper-Clad Aluminum (CCA) cable uses an aluminum (aluminum) core and is coated with copper. It contrasts with regular network cable that has a 100% copper core.

Simply put, aluminum isn't as good an electrical conductor. It has a higher DC-resistance value than copper, so more power is lost and dissipated as heat (and it only gets worse the longer the cable connection is). Higher heat and the larger power loss on the cable are both major concerns in PoE applications, so we do not recommend using them with PoE injectors or switches.

For standard networking applications, CCA cables usually get the job done just fine and cost less than 100% copper cable.
Conclusion: Demand 100% copper network cable from your supplier for PoE applications.