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

TINLEY PARK, Ill.–(BUSINESS WIRE)–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.

Contacts

Panduit Corp.
Sandy Beggs
(708) 532-1800 Ext. 81935
slb@panduit.com