Smart Buildings

The Industry’s First UL-Certified Class 4 Cabling System: Belden Digital Electricity™ Cables

Roy Kusuma

This October, the National Fire Protection Association (NFPA) is expected to publish the 2023 edition of the National Electrical Code® (NEC, or NFPA 70). Updated once every three years, the code provides installation guidelines for electrical components and systems to prevent fires and electrical accidents.


Since the 2020 edition was published in September 2019, work has been happening behind the scenes on the next revision. (Learn more about NFPA’s standards development process here.)


To make sure new safety and technology practices are addressed and implemented, 18 code-making panels (CMPs) made up of inspectors, users, installers, laborers, testing lab specialists and manufacturers (Belden included) continually collaborate to review and update the NEC.


What NEC 2023 Will Include

As part of the 2023 edition, several new articles are proposed. The new articles cover topics ranging from the use, installation and construction specifications of instrumentation tray cable to connecting alternative energy systems to utility service equipment. Included in these articles is also an update proposed by NFPA CMP 3 that will impact structured cabling: New Article 726, Class 4 (CL4) Power Systems. It was recently confirmed that Class 4 fault-managed power systems and cables will be included in NEC 2023.


Class 4 is a new classification standard dedicated to fault-managed power systems. It was created to properly bring this type of technology—which also includes packet energy transfer (PET), Digital Electricity™ (DE), pulsed power and smart transfer systems—into the NEC since it isn’t considered a Class 2 or Class 3 system.


Explaining Class 4 Power Systems

These systems provide the convenience and safety of low-voltage power, like Power over Ethernet (PoE), which offers up to 100W; however, Class 4 offers close to 20 times the power of PoE over hundreds of meters, offering a safe alternative to AC power. Class 4 systems also combine power and data in a single cable run, saving valuable installation time.


These types of systems are designed with safety at the forefront. Instead of limiting power source output like Class 2 and Class 3 systems do, they limit energy and power available during a fault event. In other words: If someone accidentally touches exposed wires or splashes water onto circuits during operation, then the system immediately and automatically shuts off before causing harm. To limit fault energy, a transmitter and receiver monitor for faults and control power delivery. This technology makes Class 4 systems just as safe as—if not safer than—Class 2 and Class 3 systems while offering more power availability.


UL Certification to Ensure Class 4 Safety

To support NEC New Article 726, UL has also been working behind the scenes to prepare for Class 4 systems, recently publishing UL 1400-2. This Outline of Investigation encompasses requirements for Class 4 cables, including DE Cables, to ensure their safe installation and operation. (We expect UL 1400-1 to be published soon as well. It will describe requirements for fault-managed power systems.)


Belden is very familiar with UL 1400-2 certification—because we helped create it. As new technologies like fault-managed power systems emerge, we think it’s important to help the industry define and support standards around their safe application.


We’re also proud to announce that Belden DE Cables are the industry’s first-ever Class 4 cabling system to receive the UL 1400-2 certification. These cables allow end users to take advantage of Digital Electricity to safely deliver lots of power across long distances using small conductors.


DE Cables were designed in conjunction with VoltServer, the creator of Digital Electricity, to ensure that they can support many types of applications. They’re available in copper-only and hybrid copper/fiber constructions to transmit power and data over long distances in a single cable run. Similar to PoE, DE Cables can be installed by the same low-voltage integrators that install Category cabling.


As smart buildings become increasingly intelligent, you’ll see Digital Electricity Cables used to support:



In the future, it will be necessary to operate these systems with a Class 4 Listed cable that complies with UL 1400-2—and Belden is honored to be the first to offer a portfolio of UL-certified Class 4 cabling.


The UL certification is happening in phases. First to be certified are Belden’s indoor/outdoor copper Digital Electricity Cables—soon to be followed by other cable constructions. We’ll keep you updated as additional DE Cables receive UL certification.


Learn more about Belden’s Digital Electricity Cables.




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Digital Electricity™: 5 Things You Need to Know