PoE in Surveillance and NVR Systems

PoE is the backbone of modern IP surveillance: each camera takes its power and its network from one cable, so there is no separate power run at the camera position, often the most awkward part of an install. The footage is aggregated and recorded centrally, either on a dedicated network video recorder (NVR) or on an edge computer that records and analyses in the same box.

The cameras are the powered devices. The source is either a PoE switch feeding a recorder, or an industrial PoE computer with built-in PoE ports that powers the cameras directly and records them, removing the separate switch. Which you choose depends on camera count, the power each camera needs, and whether you also want analytics running on the same box. Before settling on either, work out the PoE power budget for every camera at peak load, since a source’s total budget is often lower than its per-port figure suggests.

Where the equipment lives shapes the build. An indoor recorder in a comms room has an easy life; a roadside cabinet, a depot or a vehicle does not. For those, a fanless, wide-temperature computer survives the environment, and the cameras themselves need the right ingress rating. The recorder can sit centrally or out at the edge near the cameras, depending on bandwidth and resilience.

The number of channels, their resolution and frame rate, and how long you retain footage drive the storage and the recorder. More cameras and higher resolution mean more write bandwidth and more disk, which is why a surveillance computer often carries multiple drives, sometimes in RAID for redundancy. Size the storage for the retention you actually need, not the maximum the cameras can produce.

Recording is only half of what modern surveillance does. A PoE-powered computer with an NPU or GPU can run analytics on the streams it records, for example licence-plate recognition, people counting or intrusion detection, without sending video to the cloud. These are edge AI computers: doing the inference on site cuts bandwidth and keeps the footage local.

For straightforward recording, an industrial NVR captures and stores the streams. Where you want analytics as well, a PoE computer can power the cameras, record, and run the inference in one box. See our guide to industrial Power over Ethernet for the power side.