How to Lower Cabling Temperature for PoE?

Popular speaking, PoE (Power over Ethernet) is a technology that lets network cables carry electrical power. Recently, PoE has made great strides because it has shown its great advantages such as saving time and cost, flexibility and reliability. As a result, cabling for PoE is at the explosive growth rates. But there is a problem in the cabling when power is added to balanced twisted-pair cabling. The copper conductors generate heat and temperatures could rise, which may lead to higher insertion loss and in turn shorter permissible cable lengths. So, how to lower cabling temperature for PoE? Here are some advice below.

Reduce the number of cables per bundle – If the cable bundle is too big or tight, the temperature will be higher. TIA (Telecommunications Industry Association), has done an experiment about whether the number of cables can influence the temperature. First, they tested the temperature of a bundle of 91 cables, and then they equally separated this cable bundle into three bundles and tested the temperature of each bundle. The results showed that the temperature of the 91 cable bundle is much higher than the smaller three cable bundles. In order to keep the result precise and reliable, they divided the three bundles into smaller bundles, and the result turned out to be the same. So a conclusion can be reached: Separating large cable bundles into smaller bundles or avoiding tight bundles will minimize higher temperatures.

Use higher category cabling – Higher category-rated cable typically means larger gauge sizes, and as power currents increase, these larger conductors will perform better than smaller cable. There is a picture below which shows the different temperature of different category cables with the cable bundle size increased. From this picture, we can see that higher category-rated cable is capable of more stable performance as it can allow for larger bundle sizes under the maximum 15-degree temperature increase. The allowable bundle size was 52 cables for Cat 5e, 64 for Cat 6, 74 for Cat 6A, and a similar increase for Cat 8.

different temperature of different category cables with the cable bundle size increased

Install Shielded Cabling – There is a comparison between Unshielded Twisted Pair (UTP) and Foiled Unshielded Twisted Pair (F/UTP). The samples of cable were tested carrying a PoE+ current of 600 mA per pair over all 4 pairs at an ambient temperature of 60 degrees Celsius. Each cable type was coiled into a separate 90 meters length and terminated with jacks at both ends. They then applied the current while monitoring the temperature rise of the bundle. After testing, they found that UTP cable performed worst, as it required more than 9 meters of length to be removed before it returned a passing insertion loss result. While the F/UTP performed significantly better, for it can pass at less than 90 meters. The difference between the performance lies in that UTP cable has no shield or isolation wrap barrier between the insulated conductors and the outer cable jacket material. In turn, there may be an interaction that changes the dielectric constant around the conductor and contributes to greater attenuation at higher temperature.

In a word, lower cabling temperature for PoE can be benefit to reach a high quality connectivity that is a crucial part in a flexibility and reliability network. The advice introduced above will help you lower cabling temperature for PoE. In addition, Fiberstore, one of the most famous telecommunication equipment manufacturers in the world, has devoted itself to deliver the products of highest performance for cabling systems and offer the best assemblies for fiber optic connectivity, which can help you to receive maximum return on infrastructure investment.

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