Power over Ethernet for CCTV Cameras
Power over Ethernet for CCTV Cameras
Power over Ethernet, or PoE, allows compatible equipment to receive network data and electrical power through suitable Ethernet cabling. In a CCTV system, the power source may be a PoE switch, an injector, or supported NVR ports. The camera must support the required power method.
Match the source and the camera
Check the camera’s specified PoE type, class, and maximum power demand. Match these to the switch or injector’s supported standard and output. IEEE 802.3af, 802.3at, and 802.3bt describe different PoE capabilities; a PoE label alone does not establish that enough power is available.
Check both per-port power and total budget
A switch may support a stated amount per port but have a lower combined power budget than all ports at their maximum. Account for every connected device. Heaters, infrared illumination, and PTZ movement can increase camera demand, so do not size the system only from an idle reading.
Switch, injector, or splitter?
A PoE switch provides supported data switching and power. An injector adds compatible power to a network connection. A splitter can separate power and data for a suitable device, but its voltage, polarity, connector, and power capability must match that device. Do not improvise adapters or assume all splitters are interchangeable.
Standards-based PoE is not passive PoE
Standards-based PoE includes detection and power-management mechanisms. Passive power products may apply a fixed supply without the same negotiation. Verify equipment documentation before connecting an unknown injector or passive adapter.
Cabling and backup power
Use cabling and connectors suitable for the installation, required network performance, and PoE load. Respect manufacturer channel-length and environmental requirements. For outage planning, include the PoE source, recorder, and any network equipment needed for the intended operation.
Before installation
- Record camera models and maximum power requirements.
- Verify per-port and total power capacity.
- Check cable type, route, length, and terminations.
- Test operation with required heaters, lights, and movement active.
- Document the power source and backup-power plan.
Read about Ethernet cable, NVR selection, and backup power. Return to the CCTV FAQ for more answers.