Author(s): Casey Grant. Published on November 1, 2017.

Power Plan

How the research community is meeting the fire and life safety concerns associated with the evolving technology of power over ethernet

For more than 120 years, the National Electrical Code® (NEC®) has evolved alongside technology to safely achieve the fundamental task of transmitting electricity from a centralized power source to electrically powered devices. Now, another technological twist called Power over Ethernet (PoE) is at our doorstep, and code developers and researchers must again step up to meet the challenge.

PoE cables carry both data and electrical power to equipment. Powering devices with the same cables that are used to help those devices “communicate” with each other has a number of advantages, including reduced wiring costs, more design flexibility, scalable designs with plug-and-play devices, and the ability to remotely service diagnostic issues with the equipment. In a world where seemingly every electrically powered device is now connected to the World Wide Web, these advantages have resulted in PoE’s rapid proliferation.

But meshing together the cables and supporting equipment needed for power supplies along with those used for lower-energy communications devices is not a simple blend. And as with many emerging technologies, there are a few fire and life safety concerns that need to be considered.

One question being posed by experts is how PoE will fit into the current electrical infrastructure, which has evolved over more than a century. Important characteristics of wires and cables—such as type, size, quantity, and types of materials—are well-established based on the electrical loads they are expected to carry, but PoE could alter that. As PoE challenges some of these primary tenets of electrical power distribution, electrical engineers and fire protection engineers in turn must reassess some fundamental electrical and fire concerns. These include electrical shock hazards, fire ignition propensity, flame spread characteristics, fuel load, and potential products of combustion. Today, our safety record with electrical systems design is relatively good, and going forward we want to keep it that way.

Another PoE concern is the evolution of the technology itself. Though PoE has gained recognition and consideration for widespread use in the last decade, traditionally the cables only supplied low levels of power. Today, PoE cables are capable of higher electrical outputs, powering phone communications, security cameras, lighting, programmable logic controllers, mass-notification devices, and kiosk/annunciation appliances, and are used to charge all kinds of additional electronic devices. It’s not unusual to see these cables in large bundles, which raises questions about overheating and other potential hazards.

To begin addressing these concerns, in October the Fire Protection Research Foundation conducted a “Power over the Ethernet Research Planning Workshop” at the University of New Hampshire’s InterOperability Laboratory. The event was designed to identify and prioritize knowledge gaps, recommend next steps, and plan action items in support of reasonable, realistic, and safe regulatory oversight. Proceedings from the workshop will be available by November on the Foundation’s website.

While PoE is evolving, we aren’t starting from scratch. NFPA has been at the forefront of assuring safety with this technology from the beginning in numerous codes and standards. Technical committees for these codes will have to keep a close eye on how PoE evolves and proliferates.

While the Fire Protection Research Foundation workshop on PoE was an important start, it is only the beginning of a longer journey as we dive into this new era that many refer to as the “Internet of Things.” This new era, along with the devices and technologies that support it, including PoE, are here to stay. It is imperative that the regulatory community rises to address this new sweeping challenge.

CASEY GRANT is executive director of the Fire Protection Research Foundation.