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Monday, May 29th, 2017

Data Center and Infrastructure

Power over Ethernet to support needs of 5GBASE-T and beyond

Broad industry support for the development of the IEEE 802.3 standard and Ethernet’s continuing ability to evolve based on changing market needs have enabled the timely delivery of robust standards.

In mid-2015, the IEEE P802.3bz 2.5/5GBASE-T Task Force unanimously adopted the IEEE 802.3 base standard to define the physical layer specifications for 2.5GBASE-T and 5GBASE-T operating over category 5e, category 6 or better cabling.

Two important benefits of the 802.3bz standard, which could be ratified in 2016 or 2017, include support of energy-efficient Ethernet and Power over Ethernet (PoE).Click thumbnail to view larger image

Panduit Corp, the global provider of network infrastructure solutions, has been actively supporting the IEEE 802.3bz standard for 2.5G/5GBASE-T to ensure performance and interoperability of the entire ecosystem of switches, servers, PHY, connectors and cable. This effort is critical for customers seeking to deploy an enterprise network that is low cost, provides PoE and offers backwards compatibility over multiple data rates.

Early the previous year, the Ethernet Alliance global consortium had formed its Power over Ethernet Subcommittee to support IEEE 802.3 projects encompassing PoE, 10, 40 and 100 Gb/s Ethernet, Next Generation Passive Optical Networking (EPON), and more. For example, 4-pair PoE, being standardized in IEEE P802.3bt, will deliver at least 49 W to thin clients or other applications like intelligent building management systems.

Temperature tests

The shifting Ethernet landscape encompassing a broader spectrum of technologies and a diversity of new challenges has intensified the need for reliable power.

Ethernet-networked items, such as digital signage, next-generation wireless access points, nurse call stations, and thin clients, have power needs beyond the existing PoE+ standards. This has rallied the industry to develop PoE++ equipment that will supply 51 to 71 W. Such equipment could be launched as early as this year.

In installing cabling and connectivity with the PoE+ and PoE++ standards, Panduit officials have pointed out that the cables and connectors by themselves can handle the 960 mA current and the 71 W of power. The real issue lies with heat and temperature rise that occurs when the cables are bundled, causing cable insertion loss and bit errors for applications.

Extreme temperature exceeding the recommended cable operating range can damage the cable while arcing that occurs when a plug is removed from a connector with live PoE can damage plug and jack contacts and make transmission through them impossible.

The Telecommunications Industry Association (TIA) TSB-184 provides guidance for installing cables that run PoE with currents up to 600 mA on 2 pairs while the TSB-184-A upgrade offers guidance for POE++ which is up to 960 mA on 4 pairs. TIA recommends that a bundle of cables should not exceed a 15oC temperature rise within the center of the bundle. The temperature rise depends on the size of bundle; current running through the wire pairs and number of energized pairs; and cable wire gauge and construction.

For example, if 96 cables are needed to run between floors, it is possible to have a large bundle of 96 Cat 6A cables for PoE++, or four smaller adjacent bundles of 24 Cat 6A 28 AWG to run PoE and limit the temperature rise to 15oC.

Meanwhile, the International Electrotechnical Commission (IEC) has developed test methods IEC 60512-9-3 and IEC 60512-99-001 to address the issue of arcing.

Panduit has provided guidance with TSB-184-A through tests on diverse selection of cables and temperature rise measurements in varying bundle sizes having a variety of currents applied. Further, Panduit plugs and jacks are designed to pass the test methods of IEC 60512-9-3 and IEC 60512-99-001 to minimize damage to the critical plug and jack mating point.

Panduit offers small-diameter solutions that use wire gauges such as 26AWG or 28AWG to allow for better cable management, improved air flow and increased capacity in existing wire trays.


Panduit recommends having a diversity of power delivery to ensure redundant power sources and room for future data and power needs. This entails running two Category 6A cables to each powered device and having each run of the Cat 6A cable coming from a different zone distribution area.

For example, by running two Category 6A cables that can each support 10GBASE-T and 71 W of power, it can be assured that the cabling infrastructure will be future proofed to support power requirements for the foreseeable future.

Panduit recommends all new installations use Category 6A due to the fact it supports the highest data rate of 10GBASE-T, and has no bundle size limitations with any current or future PoE application.

Case study

One of Panduit's award-winning PoE projects is the Cisco Canadian headquarters, a LEED-certified smart building. It is a large-scale commercial high-rise that operates on a single, converged IP network, with electricity delivered primarily via PoE. A structured Cat 6 cabling infrastructure delivers both communications and primary electrical power.

These features deliver efficiency and lower operating cost as well as a comfortable and practical working environment. Panduit cabling provides the PoE connections to power HVAC controllers, closed-circuit cameras, door locks and LED lighting. The building features 1,400 PoE LED lighting fixtures and 1,800 PoE controllers for the HVAC system.

The new Cisco Canada Headquarters has been hailed as a living example of how organizations can harness the power of the Internet of Everything to create a smart building that’s truly sustainable and energy efficient.

This is a QuestexAsia feature commissioned by Panduit.