PoE for CCTV cameras explained
Power over Ethernet (PoE) sends power and data down the same network cable, so an IP camera needs one cable and no power supply at the camera.
PoE standards
| Standard | Power per port | Typical devices |
|---|---|---|
| PoE (802.3af) | Up to 15.4W | Most fixed cameras, intercom stations, access points |
| PoE+ (802.3at) | Up to 30W | Cameras with heaters or strong IR, small PTZs |
| PoE++ (802.3bt) | 60W to 90W | Large PTZ cameras, multi-sensor cameras |
PoE budget
A PoE switch or NVR has a total power budget as well as a per-port limit. Add up the maximum power of every camera on it and leave around 20% spare. For example, eight cameras at 7W each need 56W, so a switch with a 65W budget is tight and one with 120W is comfortable.
Distance
Standard PoE runs up to 100 m on Cat5e or Cat6. For longer runs, use a PoE extender, or cameras with ePoE (Dahua), which reach up to 800 m at lower speed.