PoE vs. PoE+ vs. PoE++: What’s the Difference?

PoE, PoE+ and PoE++ are different Power over Ethernet standards. They all allow electrical power and data to travel over Ethernet cabling, but they don’t provide the same amount of power.

The original PoE standard can supply up to 15.4 watts from the power source. Newer PoE++ technology can supply up to 90 watts. Those higher power levels have allowed PoE to support a much wider range of connected devices.

If you’re looking for a broader introduction to the technology, see What Is Power over Ethernet (PoE) and How Does It Work? Here, we’ll focus specifically on the differences between the PoE standards.

What Are the Different PoE Types?

Power over Ethernet standards are developed by the Institute of Electrical and Electronics Engineers (IEEE). The current standards are commonly divided into four PoE types.

The two power columns are different because some electrical power is lost as it travels through the Ethernet cable. PSE power refers to the power supplied by the network equipment. The lower number is the maximum power available to the connected device.

What Is Standard PoE?

Type 1 PoE is based on the IEEE 802.3af standard. It provides up to 15.4 watts from the Power Sourcing Equipment, or PSE, with up to 12.95 watts available to the connected device.

This was enough for many of the devices that drove the early adoption of PoE, including VoIP phones, basic IP cameras and other low-power network equipment.

Type 1 is generally what is meant when equipment is simply labeled PoE.

What Is PoE+?

PoE+ is Type 2 PoE and is based on the IEEE 802.3at standard.

It increased maximum PSE power to 30 watts, with up to 25.5 watts available to the device.

The additional power made Ethernet power practical for equipment that couldn’t operate within the limits of the original standard, including more advanced cameras, wireless access points and other connected devices.

What Is PoE++?

PoE++ covers the higher-power Type 3 and Type 4 standards introduced under IEEE 802.3bt.

Type 3 provides up to 60 watts from the PSE, while Type 4 increases that to as much as 90 watts.

IEEE 802.3bt also allows power to be delivered using all four twisted pairs in an Ethernet cable. This is commonly called 4-pair PoE.

Higher available power has helped expand PoE beyond traditional IT equipment into applications such as LED lighting, building controls, automated shades and other connected building devices.

Does a 90W PoE Port Always Supply 90 Watts?

No. A 90W PoE port is capable of supplying up to 90 watts, but that doesn’t mean it sends 90 watts to every connected device.

Standards-based PoE equipment determines whether a compatible powered device is connected and how much power it requires. A device that needs much less power can still be connected to equipment capable of higher-power PoE.

This also makes it possible for devices with different power requirements to operate on the same network.

Are PoE, PoE+ and PoE++ Backward Compatible?

In general, standards-based PoE equipment is backward compatible.

For example, a Type 4 PoE++ switch can typically support a device designed for Type 1 PoE or Type 2 PoE+. The connected equipment doesn’t have to use the full power capability of the port.

Compatibility should still be verified when selecting equipment, particularly when proprietary or non-standard power methods are involved.

Which PoE Type Do You Need?

The right PoE type depends on the power requirement of the device being connected.

A device requiring 10 watts doesn’t need Type 4 PoE simply because 90W PoE is available. A device requiring 50 watts, on the other hand, can’t be supported by a Type 1 or Type 2 connection.

It’s also important to look beyond the rating of a single port. PoE switches have a total power budget that determines how much power can be supplied across all connected devices.

We’ll cover that separately in How Do You Calculate a PoE Power Budget?

For system design, the starting point is simple: determine how much power each device requires, identify the PoE standard capable of providing it, and make sure the network has enough total power for all connected devices.

That’s the main difference between PoE, PoE+ and PoE++: each newer standard increases the amount of power that Ethernet infrastructure can deliver.