Ecmweb 8234 6 2 16wwhlarge
Ecmweb 8234 6 2 16wwhlarge
Ecmweb 8234 6 2 16wwhlarge
Ecmweb 8234 6 2 16wwhlarge
Ecmweb 8234 6 2 16wwhlarge

What’s Wrong Here? Hint: In and Out

June 2, 2016
Can you identify the Code violation(s) in this photo?

How well do you know the Code? Think you can spot violations the original installer either ignored or couldn't identify? Here's your chance to moonlight as an electrical inspector and second-guess someone else's work from the safety of your living room or office. It's your turn to identify the violation.

Hint: In and out

Find the Answer

This NM cable has lots of sharp bends in it. Some of these bends appear to have kinked the cable, which could indicate that the cable jacket or the conductor insulation has been compromised. Bending NM type cable this sharply is a sure way to damage the wires.

According to Sec. 334.24, bends in NM cable must be made in such a way as to not damage the cable. The bending radius of the curve must be at least five times the diameter of the cable. For an example, if we use some typical manufacturer’s dimensions of 12/2 NM cable, we could say that the outside diameter of the smaller dimension might be approximately 0.16 in. Therefore, any cable bends in the smaller diameter would need a curve radius of 5 x 0.16 inches, or 0.8 in. This would be the equivalent of bending the cable around a 1.6 in. diameter ball. As you can see in the photo, the bends at the lowest portion of this cable are very sharp and have a bend radius that is much too small. In fact, these cables are bent at a 90 degree angle. This is not what you want to do when installing this type of cable.

Lastly, since this building is a store, Sec. 334.10(3) requires this NM cable to be concealed behind a 15-minute thermal barrier, such as ½-in. sheetrock.

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.

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