Power over Ethernet (PoE) is a technology which use network to provide equipment with direct current. Since the nineties of the 20th century, PoE technology with reliable and cost-effective features have been widely respected, PoE equipment is also very common in our daily life, then, what kind of cable we should use to PoE equipment power supply? This tutorial will give you an answer.

PoE standard

IEEE802.3.af and IEEE 802.3.at are the first standards for PoE, and these two standards of power supply can provide 15W and 30W of direct current to the PoE equipment via cable, respectively. These two standards are generally suitable for low power PoE devices such as IP phones, wireless APs and some cameras. In order to meet the needs of high-power PoE equipment, people later developed the IEEE 802.3.bt standard, in line with this standard power supply equipment can provide high-power PoE equipment with 60 watts or even 100 watts of direct current. However, when supplying power to high-power PoE equipment, the cable is prone to heat, and if handled improperly, it may cause damage to the equipment and the network cable. Therefore, not all network cables are suitable for powering high-power PoE devices. In general, in the choice of network cable to the PoE device, we should take into account the structure of the cable, the size of the conductor and other factors.

Factors to consider when selecting a network cable for a PoE device

For high-power PoE devices, it is important to use a suitable network cable, which is a basic requirement to ensure network transmission quality and reliability. In general, the following points should be noted when selecting a network cable for high power PoE devices:

Conductor size

The resistance of the wire conductor is the main reason for the heat of the network cable. In general, the size of six types of cable and seven types of cable wire are larger than the ultra-five types of cable, and the larger the size of the conductor, the smaller the resistance, the less heat generated, for example, the heat generated by six types of cable super Five lines of 80% of the network. As a result, the larger the conductor is, the more suitable the high-power PoE device will be.

The construction of the cable

The construction of the network cable is also one of the reasons for the heat. According to the different structure, the network cable can be divided into non-shielded cable and shielded network cable. It is proved that the shield with a metal foil shielding cable has a better cooling performance than non-shielded cable heat dissipation performance. For example, in the same environment, the six types with aluminum foil total shielding of cable have more than 40% heat dissipation than the six types of non-shielded cable, and double shield (the total shielding for the screen, the line shield for the aluminum foil shield) seven types of cable cooling performance than the total shielding of six types of aluminum cable cooling performance it is good.

Temperature rating of the cable 

The common temperature ratings for the cable are 60 ° C, 75 ° C and 90 ° C, and the higher the temperature rating, the more powerful the power loss in the network cable. If the cable temperature is too high, it will reduce its electrical performance, affecting the physical properties and life of the cable, but compared with non-shielded cable, shielded cable is more vulnerable to temperature.

Network cable deployment

The deployment of the network cable also has a significant impact on its temperature, in general, if a lot of cables into a bundle of air is not in place will cause the network cable a high thermal conductivity, the number of cable bundles, the higher the temperature .

Conclusion

PoE equipment is widely used in all aspects of our lives, such as IP cameras, wireless access IP, etc., in order to protect the performance of these PoE devices, we should choose the conductor size, good heat dissipation performance cable.