IMC and Dissimilar Metals

April 10, 2015
Article 342 covers the use, installation, and construction specifications for intermediate metal conduit (IMC) and associated fittings.

Where practicable, contact of dissimilar metals shall be avoided in an IMC raceway installation to prevent ______.

a) corrosion
b) galvanic action
c) shorts
d) none of the above

See answer and applicable Code reference

The correct answer is: b) galvanic action

Article 342 covers the use, installation, and construction specifications for intermediate metal conduit (IMC) and associated fittings. As noted in the first sentence of Sec. 342.14, "Where practicable, dissimilar metals in contact anywhere in the system shall be avoided to eliminate the possibility of galvanic action."

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.

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