Power over Ethernet (PoE) is a way to safely transmit electrical power and data over standard structured cabling to remote devices where there may not be a power outlet or where it is too expensive to install a new outlet or bring in additional electrical service.


“PoE uses Internet LAN [local area network] cables to deliver low-voltage power up to 60 volts [V] to an array of devices,” said Masood Shariff, engineer senior principal in the systems engineering group of Commscope Inc., Hickory, N.C.


The idea of providing both communications and power to a device through one cable was born in the 1980s. At that time, users began to shift from permanently mounted telephones that didn’t require electrical power to ones that were voice over Internet protocol (VoIP) based.


“The initial PoE technology operated at around 15 watts,” said Jim Sinopoli, managing principal of Smart Buildings LLC, Spicewood, Texas.


By 2003, low-voltage devices—such as security cameras, access-control and card-reader systems, wireless access points, some home automation sensors and lighting controls—and even some basic building automation systems started using PoE.


Three forms of PoE technology are available. The original IEEE 802.3af standard for PoE provided for a minimum of 12.95 watts (W) over a nominal voltage of 48V. By 2009, the PoE+ standard provided roughly 30W, while today’s PoE++ (or Ultra PoE) goes up to 60W.


“The end-device being installed will dictate the type of PoE and wattage required,” said Curt Carlson, product manager for enterprise and government products for Transition Networks Inc., Minnetonka, Minn.


Driving the resurgence


As additional alternating-current devices—such as terminal devices in the financial industry, which require up to 45W; televisions; contemporary building-
system controls; and smart lighting controls—become candidates for PoE, the technology will become an increasingly popular option.


PoE offers many other benefits that can help to drive its continued resurgence. For example, by eliminating the need to install separate electrical wiring and power outlets, a PoE system can save the end-user up to 50 percent of the overall installation costs when used in VoIP, wireless LAN and IP security applications.


A common end-user benefit of combining power and data into one network is more intelligence and flexibility in delivering, managing and coordinating power usage.


“Every PoE controller device in use today is smarter than ever and knows what kind of power each device it is connected to needs and when and how to deliver that power,” Shariff said.


In addition, the fact that the IEEE standards for PoE technology are international enables larger companies to deploy PoE across their entire enterprise, Sinopoli said. Additional benefits include reduced costs for the end-user’s overall network infrastructure and safety.


“For electrical contractors, PoE can allow them to extend their reach and leverage existing skill sets to create new market opportunities,” Sinopoli said. 


Electrical contractors (ECs) can also use PoE to help customers monitor and analyze sophisticated device operations. 


For their own businesses, ECs can create monthly revenue streams by providing analytics and generating new ways for building owners to experience further efficiencies.


“With the increased low-voltage expertise gained from installing devices that use PoE technology, contractors can become more of a single-source installer for their customers,” Carlson said.


As with any technology that people are not familiar with, there is a bit of reluctance to adopt it. 


“It will take some time and degree of education to overcome people’s hesitation and build the confidence that PoE solutions are as reliable, robust and safe as traditional power and data systems,” Shariff said.


In addition, some devices, like videophones or computer desktops, require higher levels of power than is currently available with PoE technology, creating a barrier to wider acceptance. 


“As standards organizations define the next level of power in PoE systems, manufacturers can create the devices that will be connected to those PoE cables,” Carlson said.


Contractors need to understand PoE’s ability to integrate power with smart devices in buildings’ automation systems, and they need to better understand the various low-voltage systems that can use PoE, such as security systems.


“They also need to learn about Ethernet cabling, including how to install it, where it’s used and its capabilities,” Sinopoli said. 


Many organizations, such as BICSI, focus on low-voltage systems and standards and provide training.


As more devices are equipped with communications capabilities, PoE will become an increasingly necessary alternative for cost-effectively wiring power and operating those devices.


“PoE has become the largest single worldwide application for networking and power and will only continue to grow with the next generation of applications,” Shariff said.