Power over Ethernet (PoE) carries power and data on the same network cable, so each camera needs only one cable run and no local power outlet. It also lets you power cameras from a central UPS. Planning comes down to three checks: the right standard, enough power budget, and cable runs within limits.
PoE standards at a glance
| Standard | Common name | Power at the device (approx.) | Typical use |
|---|---|---|---|
| IEEE 802.3af | PoE | up to 12.95 W | Most fixed cameras, door hardware |
| IEEE 802.3at | PoE+ / High PoE | up to 25.5 W | Cameras with heaters, motorised lenses, small PTZ |
| IEEE 802.3bt | PoE++ | up to 51 W or 71 W (by type) | Large PTZ with heaters and long-range IR |
The power sourcing equipment (switch, NVR or injector) supplies a little more than the device receives, to cover losses in the cable.
Read the camera's real power draw
Use the maximum power consumption from the specifications, not the typical figure. IR illumination at night, heaters in cold weather and PTZ motors all raise consumption. An outdoor PTZ that runs comfortably on a summer day may need much more power on a winter night.
Check the power budget
Every PoE switch or NVR has a total power budget as well as a per-port limit. Add up the maximum draw of every connected device and make sure the total stays below the budget, with about 20 percent spare. A 16-port switch with a 150 W budget cannot power sixteen 15 W cameras at full load.
Cable length and quality
- Ethernet, and therefore PoE, is specified for up to 100 m per run, including patch cords.
- Use solid copper Cat5e or Cat6 cable. Copper-clad aluminium cable heats up and drops voltage under PoE load.
- For longer runs, add a PoE extender, place a switch closer to the cameras, or use fibre with a media converter.
Injectors for single devices
A PoE injector adds power to one cable when the switch has no PoE, or when a single camera needs more power than the switch port can deliver. High-power injectors are common for outdoor PTZ cameras.
Planning checklist
- List every PoE device with its maximum power and PoE class.
- Confirm per-port limits match the most demanding devices.
- Keep the total load below the switch or NVR budget, with headroom.
- Measure cable routes, not straight-line distance, and stay under 100 m.
- Put PoE switches on a UPS so cameras keep recording during short outages.
Share your camera list and cable distances with us and we will check the power plan.