Oct 23, 2017   SOURCE: BusinessWire

Power over Ethernet Testing Shows Real World Applications Are Not as Limiting as Cabling Standards Suggest

Are today’s cabling standards that govern Power over Ethernet (PoE) overly conservative? Findings from recently completed testing at the Panduit® labs indicate this is the case.

This first-of-its-kind PoE testing was a joint effort of Panduit, Cisco and Philips Lighting, who presented their findings at a recent Institute of Electrical and Electronics Engineers (IEEE) Conference in Berlin, Germany. The results were also shared in a September workshop at the BICSI conference in Las Vegas. This was the first real-world PoE test case, where power and data were transmitted over 192 cables of varying lengths, with temperature rise measured at the center of the 192-cable bundle. This enhanced test method produces more accurate results by taking into account the ‘constant power’ nature of PoE. The findings are summed up in two high-level statements:

  • Real world worst-case PoE deployment scenarios have lower temperature rise than the previous worst-case models
  • PoE cable bundles can be larger than current standards recommend

The findings have been presented to IEEE and the three sponsoring companies are developing an annex on engineered power delivery, collaborating with the IEEE’s PoE Task Group, which is working on the new Power over Ethernet standard. “In addition,” Panduit Director of Research Ron Nordin said, “we plan to work with the National Fire Protection Agency (NFPA) to provide better guidelines for the delivery of power over LAN cabling and installation best practices.” The NFPA recently enacted standards that govern installation of cabling that is delivering the highest level of PoE.

The testing focused on constant current vs. constant power. Some of today’s standards are built around constant current models – delivering the same worst-case level of current through the channel regardless of channel length. Conversely, constant power model reflects the actual IEEE PoE standard which limits powered devices to a maximum wattage regardless of the cable length. The implication of constant power is that with shorter channels, less power and current is delivered from the source, due to the lower power losses over the channel, than in the constant current models. The Panduit laboratory setup (which utilized 29,000 feet of cable) was designed with varying lengths of cable to represent a typical setup of Enterprise cabling length distribution. The power at the source was then modified to ensure that the power at the end device was held constant. Additionally, to ensure the quality of transmission during the testing, a bit error rate generator was used to transport data across the cabling.

The testing provides validated proof that will guide best practices for customer installations. The three sponsoring companies mutually agreed that the constant power methodology should be the method standards bodies refer to in generating best practices.

About Panduit:

Since 1955, Panduit’s culture of curiosity and passion for problem solving have enabled more meaningful connections between companies’ business goals and their marketplace success. Panduit creates leading-edge physical, electrical, and network infrastructure solutions for enterprise-wide environments, from the data center to the telecom room, from the desktop to the plant floor. Headquartered in Tinley Park, IL and operating in 112 global locations, Panduit’s proven reputation for quality and technology leadership, coupled with a robust partner ecosystem, help support, sustain, and empower business growth in a connected world. Learn more about Panduit.