Based on the 2023 NEC.
Question: What is the minimum distance to the concrete wall opposite a 400A 480/277 Volt 3Ø service entrance panelboard?
(A) 24 in.
(B) 30 in.
(C) 36 in.
(D) 42 in.
See answer below.
Answer: (D) 42 in.
Explanation: NEC Table 110.26(A)(1) in the 2023 NEC confirms the minimum distance to the concrete wall opposite a 400A 480/277 Voly 3Ø service entrance panelboard is 42 in.
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.