Code Quiz: Clearance Requirements Below Metal Roof Decking

Test your knowledge on raceways installed below metal roof decking.

Dec. 11, 2019

True or False?

Question: Raceways installed below metal roof decking must be installed at least 1-½ in. below the lowest point of the metal decking.

See the answer below.

Answer: False

Explanation: While it is true that Sec. 300.4 (E) requires raceways, cables, or boxes to maintain a 1-½ in. clearance from the lowest point of the metal decking, there is an exception that permits rigid metal conduit (RMC) and intermediate metal conduit (IMC) to be installed less than 1-½ in. from the lowest point of the decking. Therefore, the correct answer is false.

Lupacchino is a senior design engineer with Gaylor Electric, Inc. in Noblesville, Ind. and serves as an alternate on NEC Code-Making Panel No. 3. He is currently licensed in more than 80 jurisdictions. He can be reached at [email protected].

About the Author

John Lupacchino

Senior Design Engineer

John began his career in electrical construction as an apprentice and worked his way through the trade. He is currently licensed in more than 80 jurisdictions. With more than 35 years of experience, he now plays a vital role in Gaylor Electric’s Engineering Department, where he serves as a senior design engineer. With a focus on design engineering, quality assurance, and code compliance, he has earned the highest level of respect from industry professionals alike. John currently serves as an alternate on NFPA 70 Code Making Panel No. 3. In addition, he enjoys sharing his electrical knowledge through education. As an Associated Builders and Contractors instructor, he continues to help grow a new generation of high-performing construction leaders.