Although Power over Ethernet (POE)-based LED lighting has been in use for almost six years, it has only recently been of interest to the LED lighting industry. This may be subject to change with the recent release of IEEE 802.3bt-2018 (IEEE Revised IEEE Standard for Ethernet Standards): Release of Four Pairs of Power over Ethernet Cables.
POE was originally used in proprietary Voice over IP (VOIP) systems developed by Cisco in 2000, and each new generation of POE standards and technologies includes higher power specifications. At the same time, the efficacy of LED lamps is also increasing year by year. By 2017, the 25.5W limit set by the now-replaced IEEE 802.3at standard is sufficient to power nearly one-quarter of indoor lighting.
The IEEE Standards Board Council approved the IEEE 802.3bt standard on September 27, 2018, including some important improvements to LED lighting systems. The main driver of this improvement is the transmission of up to 90W of power over a 100m cable by using four pairs of cables. This simplifies the installation process by allowing multiple fixtures to be daisy-chained.
Other enhancements in the new specification include increasing the efficiency of current POE levels (ie, 25.5W of output power) because cable power consumption is reduced by approximately half. For example, a power supply unit operating under previous standards needs to provide at least 30 W of power to ensure that the powered device receives 25.5 W of power because the Ethernet cable can lose up to 4.5 W of power. Powering the same device under the new standard will reduce the loss to less than 2.25W and increase the efficiency by about 7%.