Code Q&A: NEC Requirements for RMC Installed in Contact With Dissimilar Metals

Oct. 12, 2023

Test your knowledge of the NEC.

Q. What are the NEC requirements if RMC is installed in contact with dissimilar metals?

See answer below.

A. The requirements for RMC installed in contact with dissimilar metals are found in Sec. 344.14.

If practical, contact of RMC with dissimilar metals should be avoided to prevent the deterioration of the metal because of galvanic action. Aluminum and stainless steel fittings and enclosures are permitted to be used with galvanized steel rigid metal conduit where not subject to severe corrosive influences.

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About the Author

Mike Holt

Mike Holt is the owner of Mike Holt Enterprises (www.MikeHolt.com), one of the largest electrical publishers in the United States. He earned a master's degree in the Business Administration Program (MBA) from the University of Miami. He earned his reputation as a National Electrical Code (NEC) expert by working his way up through the electrical trade. Formally a construction editor for two different trade publications, Mike started his career as an apprentice electrician and eventually became a master electrician, an electrical inspector, a contractor, and an educator. Mike has taught more than 1,000 classes on 30 different electrical-related subjects — ranging from alarm installations to exam preparation and voltage drop calculations. He continues to produce seminars, videos, books, and online training for the trade as well as contribute monthly Code content to EC&M magazine.