Code Q&A

Aug. 6, 2009

Q. Can we use EMT in a masonry wall, or must we use RMC?

A. Electrical metallic tubing (EMT), elbows, couplings, and fittings can be installed in concrete, in direct contact with the earth, or in areas subject to severe corrosive influences where protected by corrosion protection and judged suitable for the condition [358.10(B)]. According to the UL White Book (Category FJMX), "galvanized EMT installed in concrete on grade or above generally requires no supplementary corrosion protection." If the galvanized EMT is in a concrete slab below grade (such as a concrete floor of a basement), or emerges from concrete into earth, supplemental protection may be required.

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.