National Electrical Code

Chapter 9 of the NEC — Part 2

Feb. 2, 2021

Why Table 2 and Table 4 are helpful

You aren’t required to use the Chapter 9 tables of the National Electrical Code (NEC), but they can be surprisingly useful. Consider Table 2.

If you are bending 1-in. EMT with a one-shot bender (manual) or a full shoe (machine), what is the minimum radius? Answer: 5.75 in.
Your company is installing a machine it bought from a German supplier, and the raceway sizes are in millimeters. The specification calls for 16-mm and 21-mm tubing. What size EMT do you need? Answer: ½-in. and ¾-in.
Part of that machine’s installation package came with a length of 53-mm tubing that has to be custom-bent once the machine is set in place. What size shoe do you use, and what is the minimum radius in inches? Answer: Use a shoe for 2-in. EMT; your minimum radius is 9.5 in.

Then there’s Table 4, which is actually a collection of raceway-specific tables. Each is identified by an NEC Article number and the name of a raceway type. It gives metric and SAE dimensions for combinations of wire count and fill percentage in multiple sizes of a given raceway type.

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.