One of the first questions I ask myself with every new installation is: PoE or traditional power supply? This is a decision that affects the cost, installation time, reliability and expandability of the system. There is no one right answer - there are several scenarios in which each solution wins.
What is PoE and how does it work?
PoE, i.e. Power over Ethernet, is a technology that allows you to transmit power and data through the same network cable - Cat. 5e or Cat. 6 twisted pair. A camera connected to a PoE switch or NVR with PoE ports receives both image and power through one cable.
Standardy PoE:
- IEEE 802.3af (PoE) – up to 15.4 W per port. Enough for most IP cameras without heating.
- IEEE 802.3at (PoE+) – up to 30 W. Needed for PTZ cameras, cameras with heater or strong IR.
- IEEE 802.3bt (PoE++) – up to 90 W. Used for advanced thermal cameras and industrial devices.
Important note: a PoE switch has a specific power budget - the sum of watts available to all ports simultaneously. A switch with 8 PoE ports and a budget of 120 W will simultaneously support a maximum of four cameras consuming 30 W each. When planning the installation, I always count the actual power consumption of all devices.
Zalety PoE
One cable instead of two. For large installations, this saves a lot of time and material. Instead of running a network cable and a power cable (230V or 12V DC) separately, I run one UTP cable. Less work, fewer cable routes, fewer connectors.
Easier camera placement. I don't have to plan the installation around electrical sockets. I can mount the camera where I need it - not where there is electricity.
Centralne podtrzymanie zasilania (UPS). One uninterruptible power supply at a PoE switch or recorder protects the entire system. With traditional power supply, I would have to place a UPS next to each camera or install a power supply unit with a battery.
Diagnostyka z jednego miejsca. Modern PoE switches allow you to remotely restart individual ports - in fact, you can restart the camera without climbing a ladder. In the event of a camera failure, this saves time and nerves.
Kiedy PoE zawodzi – ograniczenia
Distance. Ethernet has a limit of 100 meters for one cable segment. For larger facilities, intermediate switches or PoE extenders are necessary. This increases cost and complicates installation.
Switch power budget. As I mentioned – the switch has a specific budget. When planning a large installation, it is easy to forget that not all ports can operate at full capacity at the same time. I have seen installations where cameras reset randomly because the switch was overloaded.
Equipment cost. A good managed PoE switch costs more than a simple switching power supply. For small installations - three or four cameras - traditional power supply may be cheaper.
Cameras analogowe (AHD, TVI, CVI). PoE only works with IP cameras. Older analog systems require 12 V DC or 24 V AC power supply - always traditionally.
Zasilanie tradycyjne – kiedy to lepsza opcja?
When modernizing an existing analog installation where the power cables are already routed - there is no point in replacing the entire thing with PoE. I'm adding it IP cameras with local power supplies and converters for existing cables.
For outdoor cameras with strong heating and IR - the camera may consume 40-60 W. A cheaper solution is a local 24 V AC power supply than an expensive PoE switch with a high power budget.
At very large distances - over 90 meters - low-voltage power supply (24 V AC) via a two-core cable is a simpler and cheaper solution than building intermediate network nodes.
My standard in practice
In a typical office or warehouse installation, I use an NVR with built-in PoE ports for up to 16 cameras. This is the simplest possible solution - camera, UTP cable, recorder. No additional power supplies, no additional electrical wiring.
For larger installations, I use managed PoE switches (usually Ubiquiti UniFi or TP-Link TL-SG2428P) and build a separate VLAN for cameras - which I write about in the article about network segmentation.
If you are planning an installation and wondering which solution will be better in your case, I will be happy to advise you. Each object is different and it is worth adjusting it before work begins.