power over ethernet

Power over Ethernet lets you run both power and networking to certain devices through one Ethernet cable. It's extremely convenient, especially if you have a managed PoE switch, because you get the following benefits:

• A single cable for power + Ethernet (no need for separate power adapters)
• No need to have electrical service near every device
• Simple remote power on/off capability (assuming you have a managed switch)
• Centralized power management (e.g. one UPS in a rack room covering all powered devices)

I have used the Raspberry Pi PoE and PoE+ HATs for years now, allowing me to have 4 or 5 Raspberry Pi per 1U of rack space, with all wiring on the front side. I also use PoE for cameras around my house, though there are dozens of use cases where PoE makes sense.

The Raspberry Pi, since it only requires 3-10W of power, is an ideal candidate for PoE, assuming you can find a HAT for it.

The PoE+ HAT powers a Raspberry Pi 3 B+ or 4 model B over a single Ethernet cable, allowing you to skip the USB-C power adapter, assuming you have a PoE capable switch or injector.

Unfortunately, I would recommend the original PoE HAT over the newer PoE+ HAT for most users—though Raspberry Pi have redesigned the HAT slightly and it's more on par with the original, though hard to distinguish which model you're getting. (Updated mid-2023)

For more background on PoE in general, and a bit more detail about the board itself and my tests, please watch my video on the PoE+ HAT—otherwise scroll past it and read on for all the testing results: