Issue link: http://www.e-digitaleditions.com/i/1327492
January/February/March 2021 I 33 temperature rating result in a higher LP rating and more wattage to the device without bundle size restrictions, thereby simplifying cable installation. WI-FI STANDARDS KEEP PACE WITH DEMAND The key driver for the growth of today's 90W PoE networks is the proliferation of high-powered WAPs for use in IoT networks. In discussing these wireless applications, the industry is using new, simplified terminology recently released by the Wi-Fi Alliance to replace the original designations: • 802.11n is now known as Wi-Fi 4 • 802.11ac is now known as Wi-Fi 5 • 802.11ax is now known as Wi-Fi 6 (802.11ax6E Wi-Fi 6E for unlicensed 6 GHz spectrum) 2 • 802.11be (now under development by the TSB task force) will be known as Wi-Fi 7. The tremendous growth in the number of wireless devices used for IoT applications has resulted in an explosion in data rate transmission. Wireless standard data rates have risen from 100 Megabits (Mb) to 1 GB/s and 10 Gb/s over a period of 17 years. HOW LP RATINGS IMPACT CABLE DESIGN AND CHOICES As mentioned, heat rise is a primary concern when it comes to LP ratings. The cable's temperature rating is one of the most important factors for determining heat rise and LP ratings. The higher the temperature rating, the higher the LP rating it will receive. A cable's temperature rating is affected by several factors: • Insulation material used on copper conductors: This is usually a fluoropolymer for plenum cable and a high-density polyethylene for riser cable; most commercial category cables use PVC jackets. A 100 percent fluorinated ethylene polymer (FEP) insulation will have a higher rating than partial FEP or polyolefin insulation used in riser cable. While a cable does not need to be plenum-rated to receive an LP rating, the materials used in plenum cables usually give a higher temperature rating and, therefore, a better LP rating performance. • Gauge size: Lower resistance in the cable improves heat performance. A larger copper size (denoted by a lower gauge number) generates less heat and is better at mitigating heat rise. Category 5e cable uses 24 AWG copper, while Category 6 and 6A use 23 AWG (some specialty cable products on the market now use 22 AWG copper). • Use of discontinuous metallic tapes: Some Cat 6A cables include discontinuous metallic tapes in their construction to prevent alien crosstalk. These cables provide better heat dissipation largely because the metallic tape in their construction works as a heat sink, providing a path for heat to escape the cables and decrease heat rise. To summarize, heat rises as more power runs through the cable. In testing, under high-power conditions, Cat 5e cable showed higher heat rise, while Cat 6A showed the best performance. Lower heat rise and higher Today, 90-100W PoE can power devices and systems, such as advanced lighting, videoconferencing, and the rapid proliferation of high-powered WAPs. These power-hungry applications are driving users to install a more robust 6A cabling infrastructure.