What's Wrong Here?

What’s Wrong Here? Hint: A Cornucopia of Connectors and Couplings

May 9, 2024

Think you know how this installation violates the NEC?

Hint: A cornucopia of connectors and couplings

This is not the first time I a have spotted installations where the installer was able to transition from one wiring method to another without using a transition fitting. In this case, the wiring methods transition from EMT to LFMC, with an EMT connector threaded into one end of an RMC coupling, while the other end of the RMC coupling has a 90° LFMC connector threaded into it.

One concern I have is the possibility of the internal threads of the RMC coupling potentially being a cause of damage to the conductors inside the raceway. Another concern I have is the connectors having external threads being connected to a coupling with internal threads. Both of these connectors are designed to be secured with a locknut. The threads on these fittings are not tapered as the threads on RMC are tapered. That RMC coupling is designed to be used with conduit having tapered threads. Using fittings with wiring methods other for than which they are listed is a violation of Sections 110.3(B) and 300.15.

About the Author

Russ LeBlanc | Owner

Russ started in the electrical trade as an apprentice in 1985. He worked his way up to become a Journeyman Electrician and then eventually became a Master Electrician and Licensed Construction Supervisor. In 1999 Russ become an Electrical Instructor for The Peterson School of Engineering in Massachusetts where he developed his passion for teaching, and quickly became Department Head of Electrical Instruction. Russ has taught thousands of apprentices, electricians, engineers, inspectors, and other electrical professionals during his career as an instructor. He continues to provide electrical professionals with Electrical Code seminars, Arc-Flash Awareness training seminars and educational material through his LeBlanc Consulting Services in North Reading, MA whose specialty is educating electricians. He has been an active member of the NFPA Electrical Section and has authored hundreds of National Electrical Code proposals and comments which have become Code rules to improve the safety for the electrical industry. Russ is also an IAEI certified Electrical Inspector.

Please visit www.russleblanc.net for more information.