CCTV Power Supply: PoE vs 12V DC Security Camera Wiring

PoE technology allows network cables (like CAT6) to carry electrical power along with data. In a PoE CCTV setup, your cameras plug directly into a PoE NVR or a network switch. This eliminates the need to run separate electrical mains cables or power adapters to each camera location.

The Basics of Power over Ethernet (PoE) for CCTV

PoE operates on safe low-voltage DC (usually 48V under IEEE 802.3af/at standards) and automatically negotiates power delivery. This means you cannot damage a non-PoE device by plugging it into a PoE port, making it highly user-friendly for DIY installers.

Traditional 12V DC Power Supplies: When Are They Used?

Older analogue CCTV systems and some budget wireless cameras rely on separate 12V DC power cables. These systems use a central power supply box (with individual fuses for each camera channel) or separate plug-in wall adapters.

12V DC wiring suffers from voltage drop over long cable runs. If you run a thin power cable more than 20 metres, the voltage at the camera may drop below 11V, causing the camera to reboot constantly or fail to turn on its night-vision LEDs. This is a common issue on DIY setups.

PoE Switches vs PoE NVRs: Designing Your Layout

There are two ways to build a PoE camera network. The simplest is a PoE NVR, where the recorder has built-in PoE ports on the back. You plug each camera directly into the NVR, creating a plug-and-play, isolated network.

The second, more flexible method is using an external PoE switch. The cameras plug into the switch, and a single link cable runs from the switch back to your router or NVR. This layout is ideal if you have multiple cameras on a garage or garden office, as it saves running multiple long cables back to the main house.

Installation Safety & UK Electrical Regulations

Because PoE and 12V DC are low-voltage systems, they do not fall under the strict Part P registration requirements of UK Building Regulations. Homeowners can safely run these data cables themselves without hiring a certified electrician.

However, the central NVR and any PoE switches must be plugged into standard 230V mains sockets. Ensure these devices are installed in ventilated areas, and never overload extension leads or daisy-chain power strips in your loft or utility cupboard.

Video Walkthrough

CCTV Power Supply Comparison