Ethernet Cable are being used to linked the different network devices. PoE (power over Ethernet), is a technology that can transport data and power over single Ethernet cable. PoE devices take the twisted pair in category cables to send the power. While buying PoE products, you may find IEEE802.3 standard always stand up. The IEEE 802.3 specifics how the power should transported in Ethernet cable and what is the maximum power budget. The IEEE802.3af supply 15.4 watts and IEEE802.3at (also name PoE+) supply 30 watts, which fit for lower power consumption devices like IP cameras, access points, VoIP. IEEE802.3 bt is the next generation PoE power which can offer 95 watts power . It benefits high power demanding equipments such as Televisions and interactive displays, Point of Sales (POS) and information kiosks. Therefore, different network devices may need different power and the suitable cable should be picked to match the requirements.
Considering 4 factors before picks the cable for PoE.
- Speed
There’re many cables with different speed on the market, including Cat3, Cat5, Cat6, Cat7 and so on.
From the table, it is clear to know cables’ speeds are different. Nowadays, most of home and business network have 100Mbps even 1000Mbps network. Cat5e should be the minimum choice today. If cables are being using in large computer communication or data transmission, Cat6 and Cat7 should be considered as well.
- Conductor Size and Material
As we know, conductor’s resistance brings bad effect on power transmissions. The electric currently pass through cable and convert to the heat because of the inline resistance. While the conductor size is small, the resistance is larger and the heat will be higher as well. Usually the cat6 and cat7 cable has the larger dimension than cat5 and cat4. If there is too much power loss cable inline, the remote powered devices may don’t have enough voltage to start up. Pick the bigger size conductor if possible.
Moreover, what made of the conductor does matter. Some manufacturers try to cut off cable costs by using copper-clad (or dipped) aluminum wires to replace pure copper core, which leads to higher resistance. It is going to accelerate the power loss inline. Check the cable’s material. It must be fit into the standard specification. Generally, pure copper is always the best.
- Plenum-Rated/Temperature
Other than the core of the cable, the outer skin needs to be checked. The plenum rated is relative to fire requirement. Check the fire code especially when the cables are been deployed to the public facilities such as Hospital, hotel, city hall. Air and water causes negative impact to cables in outdoor application. The cables are easy to get damage somehow while it is exposure directly. Choose the Cable with UV resistance can greatly reduce contact with air and provides better waterproof rate.
Common temperature ratings for cables are 60°C, 75°C and 90°C. If the temperature rises up in the environment, the electrical performance will become worse. Estimate the operating temperature before picking the cable.
- Installation
No matter what the cable category and construction structure, while large bundle of cable stick together, it will make heat accumulated which could cause safety issue. Be careful this could turn into problems while installing the cables in the dense place.
Cable speed, conductor size, material, plenum-rated, temperature and installation need to be overseen before choosing the cable. In addition, price is also a factor. If the cable are being selling too lower price, it may need to double confirm the quality. We mentioned the long distance power transport will make the voltage drop. Different voltage can be applied to power over Ethernet (PoE) cable.
Click here show you Long distance IP Camera setup with PoE network extender.