Power over Ethernet (PoE) has quickly become the standard for digital buildings that are embracing Internet of Things (IoT).
In simple terms, PoE technology sends power and data through one cable. Among its many benefits, PoE reduces installation costs, and provides more flexibility when it comes to locating powered devices.
Without PoE, digital buildings would be much more challenging (and expensive) to design and build. A single IP network is replacing several different (and previously standalone) networks, each which had its own wiring, connectors and pathways. Before PoE, these systems may have been able to come together over one IP network for improved control and monitoring, but they would all still require separate data and electrical connections, as well as proximity to electrical outlets.
The ease of deployment and technical advancements in end devices are driving the need for more power to be delivered over data cabling. Building systems like LED lighting, digital signage, videoconferencing, security cameras with pan/tilt/zoom features, PoE computers and high-powered wireless access points, for example, all require up to 100W of power. As a result, PoE standards have changed to safely and efficiently support higher power levels.
IEEE 802.3bt is the newest PoE standard (currently under development). It calls for:
- 4-pair power delivery to improve efficiency and support complex devices that generate more data
- Two power variants: Type 3 (60W) and Type 4 (100W)
So what does 100W PoE mean for you? It depends on who you are …
100W PoE: Considerations for Network Managers
Category 6A Cables
Using Category 6A 4-pair balanced twisted-pair cabling is critical for new 100W PoE installations. Less power is dissipated in a Category 6A cable, so more of the power running through the cable is actually being transferred to the device instead of being wasted.
Some Category 6A cables also have enough insertion loss margin to handle the extra heat generated when PoE cables are bundled. By running Category 6A cables to each powered device, and implementing a zone distribution architecture, you’ll create a futureproof infrastructure that can support 100W PoE and higher data rates.
PoE cable can be easier to maintain and administer. Moves, adds and changes can be completed quickly. Bringing new systems onto the network is also simple, and doesn’t require a licensed electrician (since no electrical connections are necessary). PoE voltage levels allow for efficient power transfer while still being low enough to be safe.
100W PoE: Considerations for Installers
Bundle sizes and cable tray densities are important when it comes to 100W PoE. As PoE levels increase, so does the cable current level. In these situations, higher PoE power levels (like 100W PoE) can cause performance issues. If cables are tightly packed into trays and pathways, or are in large cable bundles, heat build-up can increase with no way to dissipate away from the cable. Smaller bundle sizes will improve heat dissipation.
A cable can fulfill its full 100 m reach under higher temperatures only when it is designed and manufactured to do so. If the cable is installed at a higher temperature than what its rating permits, it may need to be de-rated to maintain performance across shorter distances.
UL introduced the Limited Power (LP) certification to address concerns about cable temperature rise in PoE applications. UL certifies cables with insulating and jacketing material to ensure that the cabling doesn’t exceed jacketing temperature ratings under certain conditions (after correcting for an ambient temperature of 45 degrees C). Selecting a cable with an LP certification will ensure safe operation without exceeding jacketing temperature ratings.
If an active device with a PoE connection is unplugged, an arc (spark) will occur between the plug and jack contacts. This may cause connection problems and damage jack and plug contact points. For this reason, the connecting hardware you install should pass IEC 60512-99-001 test methods. (In a successful test, after 100 cycles at 600 mA, the contact resistance change must be < 20 mΩ.)
By installing connectors that follow these testing standards, arcing won’t damage plug and jack mating points. An updated version of the IEC method – IEC 60512-99-002 – is currently in draft form. The final version will call for < 20 mΩ contact resistance change after 100 cycles at 2000 mA.
Getting Ready for 100W PoE
Belden 10GXS Cable is proven to reach distances of up to 100 m while maintaining promised performance levels despite higher heat levels. It also has a smaller diameter to save space in cable trays, and utilizes EquiBlock™ Barrier Technology to achieve uniform heat-flow dissipation while maintaining insertion loss performance. The Belden REVConnect Connectivity System is proven to pass the test method IEC 60512-99-002, ensuring that contact resistance will be less than < 20 mΩ even if disconnected 100 times at the high current level of 2000 mA per conductor.
When you’re ready, Belden can help you design and implement cabling infrastructure to support 100W PoE, reduce downtime, bring previous disparate devices to your network and support high levels of productivity. Visit info.belden.com/ecos/digital-building to learn more.
Ron joined Belden in 2016 to help define the roadmap of technology and applications in the enterprise. Prior to this, he developed cables and connectivity for Panduit and Andrew Corp. Ron Tellas is a subject-matter expert in RF design and Electromagnetic Propagation. He represents Belden in the ISO WG3 committee, TIA TR42 Premises Cabling Standards and IEEE 802.3 Ethernet Working Group. Ron is the inventor of 16 US patents. He has a Bachelor of Science degree in Electrical Engineering from Purdue University, a Master of Science degree in Electrical Engineering from Illinois Institute of Technology, and a Master of Business Administration from Purdue University.