US How a PoE powered computer works
A PoE powered computer is a computer that runs from Power over Ethernet instead of a mains adapter or DC supply. It behaves as a powered device (PD): the switch, injector or computer at the other end of the cable is the power sourcing equipment (PSE), and our PD vs PSE explainer covers the two roles.
When the cable is plugged in, the PSE first detects a valid PoE signature on the line, then the computer signals its power class, and only then does the PSE switch on around 48 V DC. Inside the computer, a PoE controller and an isolated DC-DC converter turn that supply into the voltages the board needs. Data carries on over the same cable as normal.
The result is one cable for network and power. That removes the need to run mains to the installation point, which is often the hardest and most expensive part of putting a computer on a ceiling, a pole or a remote wall.
Which computers can run on PoE
The deciding factor is power. A computer can run on PoE if its full load, including anything plugged into its USB ports, fits within the power available at the device for the PoE class on offer.
| PoE standard | Power at the device | What it can typically run |
|---|---|---|
| 802.3af (PoE) | About 12.95 W | Arm IoT gateways, small single board computers, sensors |
| 802.3at (PoE+) | About 25.5 W | Low-power x86 SBCs, thin clients, compact gateways, small touch monitors |
| 802.3bt Type 3 (PoE++) | About 51 W | Compact edge AI computers, larger touch monitors, mini PCs with low-power processors |
| 802.3bt Type 4 (PoE++) | About 71.3 W | Panel PCs and mini PCs with mid-range processors and a display |
The figures are the power left at the device after loss in a 100 m cable, as set by IEEE 802.3. Our PoE power FAQ explains source and device power in more detail. A high-power desktop processor or a discrete GPU will not fit any PoE class, so those systems need their own supply.
Examples in industrial systems
PoE powering suits computers that are small, low-power and mounted where cabling is awkward.
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PoE single board computers. Our PoE SBCs include Pico-ITX boards with a PoE-PD input, built into kiosks, sensors and OEM equipment.
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IoT gateways. Arm-based industrial IoT gateways with a PoE PD input collect data from sensors and PLCs on a DIN rail without a separate supply.
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Touch monitors and HMIs. PoE powered touch monitors take video and power from the network at a workstation or machine.
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Compact edge AI boxes. Some NVIDIA Jetson Orin NX systems run from PoE, which suits camera-side AI on a pole or gantry.
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Thin clients. Low-power desktops at a counter or production cell run from the floor switch.
PoE powered vs PoE sourcing computers
Search for a PoE computer and most results are the opposite kind: computers with PoE output ports that power cameras. Those are PSE models, and they need a large DC supply of their own, because they feed every camera on their ports as well as themselves. Our PoE computers cover both kinds, with PSE systems for multi-camera vision and NVR work and PD-powered boards and gateways for remote mounting.
The choice follows the installation. If the computer is the hub that cameras plug into, it is a PSE. If it is the remote end of a single cable from a switch, it is a PD. Our guide to industrial Power over Ethernet covers both roles and the IEEE classes in more depth.
Designing a PoE powered installation
Most problems with PoE powered computers come from the budget, the cable or the peripherals, not the computer itself.
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Check the switch budget. Every PoE switch has a total power budget shared across its ports. Add up the computer and every other PD, and leave headroom.
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Match the class. A PoE++ computer on a PoE+ port may not start, or may start in a reduced-power mode. Confirm the class each port supplies.
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Count the peripherals. USB cameras, drives and touch screens draw from the same budget. A computer that boots on the bench can fail once its peripherals are attached.
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Use good cable. Cat5e or better, solid copper and no longer than 100 m. Higher PoE classes warm the cable, so large bundles need care.
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Plan for outages. With PoE, the switch becomes the power supply. Put the switch on a UPS and every PoE powered device is backed up at once.
Quick answers on PoE powered computers
PoE powered computers: common questions
Can a mini PC run on PoE?
Some can. Mini PCs with low-power processors fit within a PoE++ budget, either built for PoE or through a PoE splitter that outputs DC. Check the full load, including USB devices, against the power at the device.
Do I need a special switch to power a computer?
A PoE switch of the right class. The switch port must supply the class the computer requests. An ordinary switch with a PoE injector in the line also works for a single computer.
Is PoE safe for a computer?
Yes, with standard PoE. Standard PoE only powers a device after detecting a valid PD signature. Passive PoE skips that check and can damage equipment not built for it.
How far can a PoE powered computer be from the switch?
Up to 100 m. That is the standard Ethernet limit for data and power together. Beyond it, use a PoE extender or move the switch closer.
Can a laptop charge from PoE?
With an adapter. A PoE++ splitter with a USB-C Power Delivery output can charge many laptops, within the power class available.
We build PoE powered and PoE sourcing computers as standard, fitting the storage, memory and modules you need and checking the power draw against the PoE class before the system ships.