802.3Af Vs 802.3At Poe For Cctv Uk

Direct answer: 802.3af is the older PoE standard commonly associated with up to 15.4 W at the power-sourcing equipment, while 802.3at, often called PoE+, raises that budget to about 30 W at the power source. For CCTV, match the camera datasheet and the switch power budget, not the nickname on the listing.

The practical symptom is familiar: a camera boots in daylight, then reboots when infrared LEDs, heaters or motors draw more power. That can look like a network fault when the real issue is power class or total switch budget.

Quick comparison

Standard	Common name	Typical CCTV fit	Installer check
IEEE 802.3af	PoE	Lower-power fixed cameras and simple indoor devices	Check camera maximum watts, not only idle draw.
IEEE 802.3at	PoE+	Many outdoor cameras, IR models and higher-demand access points	Confirm the switch supports enough per-port and total budget.
IEEE 802.3bt	PoE++ / higher power PoE	Specialist high-power devices	Use equipment specified for the class; do not assume a budget checker load-tests it.

Read the camera before blaming the cable

UK explainers such as this PoE standards wattage table and the NETGEAR PoE standards overview show why “PoE” is not one single power level. A camera that needs PoE+ may still appear to connect on an af-only port, then become unstable when load rises.

Field decision path

Read the PD power requirement. Use the camera datasheet for maximum draw, including IR, heater or pan-tilt operation.
Check per-port support. A switch may have a total PoE budget that is fine on paper but limited per port.
Add the whole switch budget. Four cameras starting night mode together can expose a marginal budget.
Verify at the camera end. If the port should supply enough power, check PoE presence at the far end, then test wiremap and length if power is absent or unstable.

Passive and non-standard PoE

Some older or specialist devices use passive or non-standard power arrangements. Do not mix them casually with IEEE PoE equipment. Keep the labels clear, read the device documentation and avoid connecting test tools or cameras that are not rated for the supply involved.

When to escalate

The UK IP camera PoE installation guide discusses matching PoE classes to CCTV use cases. If a camera only fails during night IR or cold-weather load, a simple presence check may not be enough; use a load-capable PoE verifier or call an installer with one.