Sometimes we need to look at the past to get a better view of our future. I find it somewhat ironic that although the rear view mirror in a car is nearly 90 times smaller than the windshield, the clarity it provides of what is in the past is more defined than the unknown of what lies in the ever-changing path in front of us. The same can probably be said from a lighting technology perspective. Dating back to 1879, when Thomas Edison invented the first commercially viable incandescent light bulb, made of carbon filament, we can see the different changes in lighting technology that have led us to where we are today. The path ahead – well, that has yet to be determined, but it will continue to be defined, as it always has been, by advancements in technology meeting the present-day need.
Lighting the Past
Edison’s first incandescent lamp really set the stage for future inventors to begin experimenting with improving upon it to find new, more efficient ways to deliver light. Inventors began to try different types of materials for the filaments being used within incandescent lamps. Where Edison’s initial lamps first used cotton-based, and then modified to bamboo-based, carbonized filaments in a high-vacuum glass envelope, the lamps did not have a very long lifespan. In the early 1900s, inventors began using tungsten to develop the filaments for lamps, which resulted in brighter light and longer lifespans. This time period also saw the creation of mercury vapor lamps and their distinct blue-green light they provided. About a decade later, Irving Langmuir determined that filling the lamps glass envelope with inert gases, like argon and nitrogen, reduced tungsten evaporation, which resulted in even greater efficiency and a longer lifespan. Modifying the gases utilized in lamps seemed to be the major area of focus over the next couple of decades, resulting in the development of neon lighting as well as low-pressure sodium (LPS) lamps that provided a highly efficient monochromatic yellow light that was ideal for use in street lighting. LPS was further expanded upon in the 1960s with the invention of high-pressure sodium (HPS) and metal halide lamps that have been long-used, respectively, within exterior lighting applications and for large interior spaces, such as warehouses and factories, well into the 1990s.
Lighting the Present
While the 1930s certainly cannot be considered to be present day, the lighting technology invented during that decade, most notably fluorescent lighting, are still being utilized in electrical applications today. While not as many fluorescent light fixtures are being newly installed, they are still present on some level within the homes and buildings that electrical professionals need to service. There is nothing like the distinct smell of a ballast that needs to be changed, am I right?! Fluorescent lighting and continued use of incandescent lamps dominated the 1980s and 1990s until the government stepped in the 2000s to try to better manage energy consumption. The Energy Policy Act of 2005 and the Energy Independence and Security Act of 2007 all but did away with the standard incandescent lamps that had been used throughout many years by requiring more efficient lighting, first in the form of compact fluorescent lamps (CFLs) and now in the light-emitting diode (LED) lamps that all but dominate today’s lighting market.
An interesting fact on LED lamps is that the first one was actually invented in 1927 by Russian inventor, Oleg Losev; however, the initial model was far from the extremely efficient LEDs that we see being used today. It took many decades and changes in the LED lamps colors reproduced to get to the 2000s when bright white LED lamps were available for commercial use. While extremely efficient and capable of producing immense amounts of light, those early LEDs were often seen as too bright and producing a light that was not conducive to environments that people were comfortable being in, especially within work offices and homes. As technology does, LED lamps continued to improve over the coming decades to produce a wide array of colors as well as functionality improvements, such as becoming dimmable.
Lighting the Future and Changes to the NEC
As we look toward the future of lighting, LEDs are well-established in their use and the colors that they produce; however, what seems to be changing more is the way in which they are being used. One example is where LEDs are starting to be used more and more in a horticultural application within cannabis facilities for growing plants. Shifting away from older lighting technologies, such as HPS and metal halide, to LED offers tremendous savings on power consumption. This also contributes to less burden on the electrical system within the building and the utility electrical infrastructure that is providing power to the facility.
LEDs are also being used in more human-related applications, such as therapeutic lighting and human-centric lighting (HCL). Therapeutic lighting can be used to help treat skin conditions, aid in muscle recovery, and help regulate sleep patterns. It has been suggested that HCL can have a direct impact on human well-being, mood, productivity, and circadian rhythms by adjusting the color temperature and intensity throughout the day and in different settings. Typically, HCL is integrated with smart systems that can help control and automate lighting adjustments as needed based on the time of day, occupancy, user preferences, and even real-time adjustments, such as accounting for the amount of natural daylight changing when a thunderstorm suddenly arises outside.
As technologies change, so too must the requirements of NFPA 70®, National Electrical Code® (NEC®) adapt to help ensure safe installations of this equipment and associated components. With the growth of cannabis facilities and the use of horticultural lighting on the rise, the 2020 edition of the NEC saw the addition of Part XVI to Article 410 to add requirements around horticultural lighting equipment. This new part addresses items pertaining to horticultural lighting, such as listing, installation, and use, locations permitted and not permitted, flexible connections, and ground-fault circuit-interrupter (GFCI) protection.
The 2023 NEC opened the door for energy-efficient lighting that is becoming more readily available to be better utilized by permitting the use of 10-amp branch circuits for lighting applications. Another change during this edition of the NEC cycle that may impact lighting technology is the addition of Class 4 fault managed power (FMP) systems in new Article 726. A 10-amp branch circuit lighting load may fit well within the limits of an FMP system. At base level, FMP allows for safe and efficient transmission of higher voltage and power levels over a longer distance, making it more viable to distribute loads throughout premises wiring. The means of transmission also offers a level of safety from electric shock and potential arc flash hazards because FMP has the ability to shut down as soon as a break in the line or fault is sensed. Although the addition of FMP in Article 726 of the 2023 NEC did not permit it to be used in dwelling units, the 2026 NEC was modified to allow FMP to be used in residential applications, giving it the potential to change the way we wire homes of the future for lighting and other applications.
The 2026 NEC also saw another substantial change with respect to reflecting how far we have come with the efficiency of lighting technology. For years, Article 220 of the NEC has maintained the use of 3 volt-amps per square foot (va/ft2) for calculating the minimum load for dwelling units. For the 2026 NEC, former Article 220 has become new Article 120, which continues to address branch-circuit, feeder, and service load calculations. Section 120.41 has been modified to require that the minimum load for dwelling units is now to be calculated at 2 va/ft2 instead of the 3 va/ft2 that was previously required. In their committee statement, NEC Code Making Panel 2 referenced the use of high-efficacy lighting in new dwelling units, as well as a study from the Lawrence Berkeley National Laboratory, as justification for making this change. This is a great example of how changing lighting technology over the decades has not only impacted functionality and needs-based use but has also become efficient enough to begin to impact long-standing NEC calculation requirements to now provide more latitude toward less power demand. Our rearview mirror gives us a clear picture of where have been in the development of lighting technologies. Looking through the windshield, we have a view of what is on the immediate horizon but anxiously anticipate what may be in the beyond.
The 2026 National Electrical Code (NEC) is available for immediate access in digital form though NFPA LiNK® by visiting www.nfpa.org/LiNK.
Important Notice: Any opinion expressed in this column is the personal opinion of the author and does not necessarily represent the official position of NFPA or its Technical Committees. In addition, this piece is neither intended, nor should it be relied upon, to provide professional consultation or services.
