I would like to ask why the POE power supply switch power distance 100 meters

PoE refers to the power supply switches for electric cable through the distal terminal provides network power switches, network switches and PoE power supply contains two functions, is a common power supply equipment in PoE power supply system, support port output power up to 15.4W, in line with the IEEE802.3af standard, support port output power up to 30W, in line with the IEEE802.3at standard, through the network cable powered by standard POE power supply terminal equipment, eliminates the additional power supply wiring. Accord with IEEE802.3aT
Standard POE switch port, the output power can reach 15-60W popular to say, is to support the power supply cable POE power supply switch switch, which can not only realize the function of data transmission can also supply power to the ordinary switch network terminal
POE cable requirements specifications in more than five categories (including over five categories), the proposed power supply distance of less than 90 meters, up to 100 meters. 8 core over the five categories of cable line of 100 meters, do not use bad lines, plus network extender, can extend the length of 600 meters.