PoE Update

The potential of power over Ethernet (PoE) continues to grow, creating new installation opportunities for electrical contractors doing integrated systems work.

An established and often specified media, Ethernet cabling and connectivity continue to be deployed for transmission of information, physical security and data. PoE offers the ability to deliver power efficiently and effectively over the existing infrastructure, providing a substantial cost and labor savings. It also continues to advance with the times, parlaying its increasingly robust power capabilities to better leverage integrated systems installations.

What is PoE?

PoE uses an existing local area network (LAN) to transmit low-voltage direct current (DC) power and data, eliminating the need for additional power supplies or electrical wiring. Therefore, PoE enables installers to power an end device, such as a camera or access control reader, without running a second cable. It offers significant labor and hardware savings for contractors and their customers, especially in locations where digging and trenching is difficult or restrictive.

The Institute of Electrical and Electronics Engineers (IEEE) has two established PoE standards, and a third is under development. The IEEE 802.3af PoE standard in 2003 opened the gate for equipment manufacturers to produce and leverage standards-based products that optimize the technology. Under IEEE 802.3af, 15.4 watts (W) of power were available for each powered device, which was adequate for many in-the-field PoE applications at the time.

Times have changed. Many more devices that require additional power have hit the market. A good example is outdoor surveillance cameras with pan-tilt-zoom (PTZ) functionality and those with heaters and blowers used to offset extreme cold and hot temperatures.

The industry’s insatiable appetite for greater power—and an increased emphasis on converged system solutions—has resulted in the release of another standard for PoE, IEEE 802.3at. Also referred to as “PoE Plus” or “PoE+,” it provides enhanced power delivery up to 30W for more power-hungry products, such as motorized PTZ network cameras, electromagnetic door strikes, proximity sensors, intercoms and other security devices.

Still another emerging option is High-PoE, which can deliver up to 60W over the same infrastructure by using special midspan injectors to transmit two separate 30W PoE+ feeds. A midspan is an intermediary device between a non-PoE-capable switch and a PoE device. As camera capabilities and functionality continue to increase, this technology will become more prevalent, and a developing IEEE High-PoE standard will continue to raise the possibilities and uses of Ethernet for additional applications.

According to Joseph Holland, co-founder and vice president of engineering for LifeSafety Power Inc., Mundelein, Ill., PoE continues to grow in popularity and deployment as camera manufacturers scramble to reduce power consumption needed for motorized domes and heaters, for example. Power levels and data rates have increased; power levels will rise further with the standard’s introduction, he said.

This latest higher power implementation of the current standard 802.3at is due to be released in 2017 or 2018.

“It’s currently in the draft stage, and they are making great progress on it,” Holland said. “It opens the door for new specifications not only in the security industry but for custom electronics installers, as audio and video will be able to be powered by PoE.”

High-PoE IEEE 802.3bt will pave the way for devices that require 50W or more, and the specification is supposed to be able to handle up to 100W, he said.

Holland said higher wattages have allowed the support of even higher powered devices.

“An example of one product that requires higher power is CCTV camera illuminators,” he said. “The new standard will also apply more wholly to access-control systems as opposed to simply edge devices, such as readers.”

PoE has changed in other ways, ushering in products such as smart managed midspans that allow for more detailed networking functionality and the ability to proactively address the system solution’s “health” and well being.

The role of midspans and PoE

“Managed midspans have become more popular due to their reporting and control capabilities,” Holland said.

With simple network management protocol (SNMP), the midspan can notify the network of a problem within the unit or a specific port. Port control is possible through the management software, which can turn ports off or on. In some cases, the software also provides the ability to change port behavior based on power draw or port priorities. SNMP is an Internet-standard protocol for collecting and organizing information about managed devices on Internet protocol (IP) networks and remotely accessing that information.

The midspan device provides a method to introduce PoE to the system exclusive of the network switches, thereby helping to keep heat out of network data switches and extending their life.

“A midspan that offers full power [802.3af, 15.4W and/or 802.3at, 30W] per port is the best choice for future-proofing your network because, no matter what end device you want to add—more phones with more functionality, security cameras with advanced functionality, PC 
workstations—the power is available,” Holland said.

Ethernet switches are also an important aspect of the total PoE equation, said Mark Prowten, vice president of sales and marketing for EtherWAN Systems Inc., Anaheim, Calif.

“The Ethernet switch is the critical link between the cameras, network video recorders [NVRs] and any computers that need access to video feeds,” he said. “The Ethernet switch not only provides the data connectivity but often provides the power to the IP cameras via [PoE].”

According to Prowten, Ethernet switches are the fundamental backbone of a LAN.

“The switch is the critical connectivity point for everything that needs to communicate. In other words, the switch creates the LAN,” he said, adding that, without a switch, there isn’t a LAN. “Computers, laptops, printers, IP cameras, NVRs, IP phone systems [voice over IP], Wi-Fi, building infrastructure and access control systems are now put on the LAN. None of these systems could communicate without Ethernet switches providing the connectivity. Network connectivity is everywhere and goes well beyond the security industry. Ethernet is in every industry and even our homes now.”

Prowten said contractors should steer clear of cheap or low-cost switches because they do not provide the switching bandwidth performance or enough PoE budget to power all of the cameras reliably.

“These low-cost switches are usually unmanaged, meaning there is no option to log into the switch to troubleshoot connectivity or PoE power issues,” he said.

EtherWAN Systems works closely with its channel partners, dealers, integrators and end-users to help spec the right products for the application.

“We also provide Ethernet 101, PoE, advanced Ethernet and group trainings,” Prowten said. “Training can be done face to face at contractor locations, via Web meeting, or at our HQ facility in Anaheim.”

PoE continues to grow in popularity and will evolve to embrace and support a wide range of security and other integrated technologies in a cost-effective manner.

About the Author

Deborah L. O'Mara

Freelance Writer

O’MARA writes about security, life safety and systems integration and is managing director of DLO Communications. She can be reached at dlocommunications@gmail.com or 773.414.3573.

Stay Informed Join our Newsletter

Having trouble finding time to sit down with the latest issue of
ELECTRICAL CONTRACTOR? Don't worry, we'll come to you.