NFPA Journal

I HAVE ALWAYS MAINTAINED that contractors with a thorough understanding of National Electrical Code ®(NEC®) rules enjoy a competitive advantage, not only from a first-time compliance standpoint but also from using code rules that can result in overall cost savings. With that in mind, the 2017 NEC will include a couple of new rules that will have positive impacts on safety as well as pocketbooks.

In the two most recent revision cycles for the code, the NEC code-making panel responsible for load calculations has accepted changes that can be used to reduce the overall calculated load in commercial and mercantile occupancies. The driver of these proposed changes was the increased adoption and enforcement of energy conservation codes in the United States, codes that establish requirements for efficient operation of power, lighting, and heating and air-conditioning systems in residential and commercial buildings, with the overall goal of reducing demand on energy sources. Energy codes are ubiquitous in today’s construction and code compliance worlds, and they must be compatible with construction safety codes to work in the best interest of property owners, whether the project is a single-family home or a multistory commercial complex.

The 2017 NEC has followed suit, and a change to the assigned lighting load for office and bank buildings will become available via a new exception to Section 220.12. This section and its accompanying table specify a minimum general lighting load for a number of typical occupancy types. The calculation uses a specified unit load per square foot (or square meter) of the building or portion of the building that is one of the occupancy types included in the table. The decreased lighting load results in potential savings due to smaller services, feeders, transformers, and less panelboard capacity. In cases where there is a generator, the generator itself may be smaller, along with associated equipment such as transfer switches. The fact that the energy code constricts the lighting density has the potential to reduce the overall cost of the project—a win-win in that the building is more energy efficient and the initial infrastructure cost can be reduced.

The economy of scale is in play here and the larger the building, the more impact this permitted exception will have. While a small decrease in lighting costs for a small building may not seem significant, the same reduction in a very large building can be significant. As a point of reference, the newly constructed One World Trade Center in New York City contains 2.6 million square feet (241,548 square meters) of office space.

The code-making panel has received proposed changes to reduce the minimum general lighting load values for a number of revision cycles and has taken a cautious approach to the issue—after all, it was being asked to reduce the “minimum.” Energy codes started out as a regional issue and the panel was hesitant to change the code based on local requirements. However, the landscape has changed significantly, with federal and state energy-saving mandates currently used throughout the country. With that information, the code-making panel has more experience to draw from, which in turn provides the necessary level of confidence that reducing the general lighting load is not compromising the number-one priority—a safe electrical infrastructure.

JEFFREY SARGENT is a regional electrical code specialist for NFPA.