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What Is a PoE Security Camera?
What a PoE security camera is, how Power over Ethernet works, and why one cable for power and video suits commercial installations.
PoE stands for Power over Ethernet. A PoE security camera receives both its power and its network connection through a single Ethernet cable. That single fact changes the whole installation, and it is why PoE has become the standard for commercial camera systems.
How PoE Works
An Ethernet cable has several wires inside it. In a PoE system, some of those wires carry data and some carry power, or the power is carried on the same wires as the data. Either way, one cable does both jobs. The power comes from the switch — the device the camera plugs into — so there is no need for a power outlet at the camera.
The switch has a total power budget, and each camera draws from it. A basic indoor camera draws a small amount of power. An outdoor camera with infrared lighting draws more. A PTZ camera with a heater draws more still. The design adds up the draw of every camera and checks it against the switch budget, with headroom to spare.
Why One Cable Matters
One cable matters most where cameras are hard to reach — high warehouse ceilings, outdoor walls, parking lot poles, gates at the far end of a yard. Running one Ethernet cable to each of those spots is simpler, cleaner and easier to maintain than running power and video separately.
It also makes the system easier to manage. Because power comes from the switch, a camera can be restarted remotely by cycling its switch port — a small thing that saves a ladder trip when a camera needs a reset. And because there is no separate power adapter at each camera, there are fewer components that can fail in hard-to-reach places.
PoE Standards
There are three main PoE standards. The basic standard supplies up to about 15 watts per port, which suits basic indoor cameras. The second standard supplies up to about 30 watts, which suits most outdoor cameras and PTZ cameras. The third supplies up to about 60 to 90 watts, which suits high-power cameras with heaters and multi-sensor units.
The standard matters when the switch is chosen. A switch that only supplies the basic standard cannot run a PTZ camera that needs more power. The camera list and the switch specification should be checked against each other before anything is ordered.
Limits to Know About
The main limit is cable length. A standard Ethernet run is about 100 metres. On a large property, some camera locations will be further than that from the switch, and those runs need a plan — an intermediate switch, an extender, or a fibre link. Discovering the limit after the cable is pulled is an expensive mistake.
The second limit is the power budget. If the cameras together draw more than the switch can supply, the cameras furthest away or with the highest draw will fail — often at night, when infrared lighting switches on and power demand rises. The design should total the draw of every camera and add headroom.
Is PoE Right for Your Property
PoE suits most commercial properties, because it simplifies installation, centralises power control and makes expansion easy. It is especially useful for outdoor cameras, high cameras and large properties where power outlets at each camera would be impractical.
If you are planning a system, the design should include the power budget and the cable lengths, so the switch and the cabling are sized for the cameras. A PoE system that is planned properly is a system that runs reliably; a PoE system that is not planned is a system that fails at night.
Frequently Asked Questions
What does PoE mean in security cameras?
PoE means Power over Ethernet. A PoE camera receives power and its network connection through a single Ethernet cable, so there is no need for a separate power supply at each camera.
Which switch is needed for PoE cameras?
Yes. PoE cameras need a switch or injector that can send power over the Ethernet cable, and the switch must have enough total power budget for all the cameras connected to it.
How long can a PoE cable run be?
A standard Ethernet run is about 100 metres. Longer distances need an intermediate switch, a PoE extender or a fibre link to carry the connection further.
What happens to PoE cameras in a power cut?
If the switch loses power, the cameras connected to it lose power too. That is why the switch and recorder are often connected to a battery backup, so the system keeps running through a short outage.