National Electrical Code

Making Sense of NEC Chapter 5 — Part 2

Sept. 7, 2021

Article 500 defines terms and concepts related to hazardous locations.

In Part 1, we said Chapter 5 is arranged thematically; Article 500 defines terms and concepts related to hazardous locations and provides requirements that apply to them generally. We showed the first three logical groupings (ending with Art. 540). The other logical groupings are:

540 – 555. Special kinds of structures in which people work or live. These are manufactured buildings and relocatable structures (545), agricultural buildings (547), and mobile homes manufactured homes, and mobile home parks (550).
551 – 552. Vehicles in which people temporarily work or live. These are recreational vehicles and parks (551), and park trailers (552).
555. Marinas and boatyards. This article has undergone extensive revision and expansion over the last few code cycles. The impetus for it is the many tragic electrocutions that have occurred not because of faulty equipment, but because of faulty installation practices. The underlying principle of this article is to keep water and electricity separate from each other so people are separated from electricity when in the water.
590. Temporary installations. The rules for these installations allow for the fact that each is meant for a specific purpose, after which it will be removed.

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.