National Electrical Code

Making Sense of NEC Chapter 5 — Part 1

Aug. 17, 2021

Think thematically

In Fig. 90.3, you can see Chapter 5 Special Occupancies is grouped with Chapter 6 Special Equipment and Chapter 7 Special Conditions. Each of these three chapters supplements or modifies other chapters in Chapters 1 through 7.

In the loose-leaf version, Chapter 5 covers 147 pages. Why is there so much space given for these “special occupancies? Is Chapter 5 just a collection of similar but slightly different requirements for a big list of occupancies? No, it’s arranged thematically.

Article 500 defines terms and concepts related to hazardous locations and provides requirements that apply to them generally. The articles then appear in logical groupings. For example:

501 – 510: Hazardous Locations. The three types are those with combustible gases (501), dust (502), or fibers (503). The other chapters cover other aspects, such as the zone system.
511 - 516. Places where fuel and similar solvents are inherently used, such as garages, aircraft hangers, and dipping processes.
517 – 540. Places where people may not quickly evacuate or where crowds are present. These include health-care facilities, movie theaters, and carnivals.

About the Author

Mark Lamendola

Mark is an expert in maintenance management, having racked up an impressive track record during his time working in the field. He also has extensive knowledge of, and practical expertise with, the National Electrical Code (NEC). Through his consulting business, he provides articles and training materials on electrical topics, specializing in making difficult subjects easy to understand and focusing on the practical aspects of electrical work.

Prior to starting his own business, Mark served as the Technical Editor on EC&M for six years, worked three years in nuclear maintenance, six years as a contract project engineer/project manager, three years as a systems engineer, and three years in plant maintenance management.

Mark earned an AAS degree from Rock Valley College, a BSEET from Columbia Pacific University, and an MBA from Lake Erie College. He’s also completed several related certifications over the years and even was formerly licensed as a Master Electrician. He is a Senior Member of the IEEE and past Chairman of the Kansas City Chapters of both the IEEE and the IEEE Computer Society. Mark also served as the program director for, a board member of, and webmaster of, the Midwest Chapter of the 7x24 Exchange. He has also held memberships with the following organizations: NETA, NFPA, International Association of Webmasters, and Institute of Certified Professional Managers.