What’s Wrong Here? Hint: Roof Decking Raceway Run

Feb. 5, 2020

Do you know how this installation violates the NEC? Hint: Roof decking raceway run

Hint: roof decking raceway run

While running a raceway up above the truss work may be a quick and easy way to get the job done, sometimes it’s best to take your time and do the job right.

Section 300.4(E) requires raceways, cables, and boxes installed underneath metal-corrugated sheet roof decking to be installed no closer than 1½ in. from the lowest portion of the roof decking. The reason for this spacing can be seen in the Photo. Sheet metal screws used for making repairs to the roof, are poking down through the roof decking. When raceways are installed too close to the roof deck, these screws could wind up penetrating the raceway causing severe damage to the enclosed circuit conductors. Strut could be secured to the roof deck as a means of separating the raceway from the roof. Securing the raceway to the strut would then be permitted. Of course, there are many other ways to provide the required separation too.

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.