Short answer
A PoE switch is a network switch that sends electrical power and data down the same ethernet cable. Devices such as IP cameras, wireless access points and desk phones then run from one cable, with no separate power adapter or nearby mains socket needed.
Updated 2026-09-21 · 4 min read
What a PoE switch actually does
An ordinary switch moves data between devices. A PoE switch does the same job but also injects DC power onto the spare or data pairs of the ethernet cable, up to 100 metres. The device at the far end takes what it needs and the switch keeps the rest for other ports.
The PoE standards, and what each one powers
| Standard | Name | Power per port | Typical devices |
|---|---|---|---|
| 802.3af | PoE | 15.4 W | Desk phones, basic cameras, older access points |
| 802.3at | PoE+ | 30 W | Wi-Fi 5 and Wi-Fi 6 access points, PTZ cameras |
| 802.3bt Type 3 | PoE++ | 60 W | Wi-Fi 6E/7 access points, video bars, thin clients |
| 802.3bt Type 4 | PoE++ | 90 W | Displays, small workstations, high-power devices |
Power budget is the number that catches people out
Each switch has a total power budget shared across all its PoE ports. A 24-port switch with a 370 W budget will not run 24 devices at 30 W each. Add up what your devices actually draw, then leave roughly 25% headroom for future additions.
- Count the real draw of each device, not the standard's maximum
- Leave headroom — sites almost always add cameras and access points later
- Check whether the budget is shared or per-port-guaranteed
- For resilience, look at dual power supplies or a UPS on the switch
When you need one
- Ceiling-mounted wireless access points with no power nearby
- IP camera systems — one cable per camera instead of two
- VoIP handsets, so phones stay up on the comms room UPS
- Door entry, sensors and digital signage in awkward locations
Related questions
- Is a PoE switch worth it for a small office?
- Usually yes. Even an 8-port PoE switch removes the need for a power socket at every camera, access point and phone, which is normally cheaper than paying an electrician to add sockets.
- Do I need a managed PoE switch?
- Managed switches let you use VLANs, control per-port power and reboot a frozen camera remotely. For anything beyond a handful of devices, managed is worth the small extra cost.
Hardware for this
The ranges below cover what this article describes, supplied in the UK with lead times confirmed before you commit.
PoE network switches
8, 24 and 48-port PoE and PoE+ switches with the power budget checked for your device list.
UniFi PoE switches
Ubiquiti UniFi switching for offices, schools and multi-site networks.
Cisco Catalyst switches
Catalyst 1000, 9200 and 9300 switching, quoted with the right PoE licence and optics.