Illustrated Catastrophes: Alive and Kickin’
All references are based on the 2026 edition of the NEC.
Alive and Kickin’
The voltage tester does not lie. There are many energized 277V power circuits wired with brown, orange, yellow, and black, 600V-rated, THWN-insulated conductors in this wireway and raceway. That, however, is not the problem.
The real problem is the white 18 AWG CL3P cable installed in this same wireway and raceway with those very same 277V power circuits. Some installers may think that Sec. 300.5(C)(1) allows this type of installation because the Class 3 (CL3P) cable is rated for 300V as specified in Sec. 722.140(A)(3), and all the conductors are operating at 277V or less.
However, Sec. 722.15(A) generally prohibits limited energy cables such as this Class 3 (CL3P) cable from being installed in the same raceway, compartment, enclosure, manhole, or box with power conductors unless specifically permitted by Sec. 722.15(B) through Sec. 722.15(K).
None of the prescriptive measures described in (B) through (K) were used to provide the required separation for these circuits. This type of violation is common enough to need the important Informational Note No. 2 for Sec. 300.5(C)(1), which alerts Code users to Sec. 722.15 for Class 2 and Class 3 circuit requirements.
A Pig-Pile of Cables and Raceways
Buried underneath this cluster of cables and raceways is the original ¾-in. electrical metallic tubing (EMT) raceway that was installed before all of these cables and another raceway were attached and secured to that very same ¾-in. EMT. That poor EMT is working really hard carrying all this added weight.
While the original EMT installation was probably Code compliant, the installers who kept piling on more and more cables and another raceway violated the Code by using the EMT to support their cables and raceways.
Generally speaking, Sec. 300.13(C) does not permit EMT as a means of support for other raceways, cables, or non-electrical equipment. This EMT is supporting power supply cords, communication cables, fiber-optic cables, several other types of limited-energy cables, and a communication raceway.
Section 358.12(2) also prohibits EMT from being used for the support of equipment other than conduit bodies. Some limited energy cables in this bundle are secured with cable ties to other limited energy cables in this bundle too, which is a violation of Sec. 722.30(D). Cables cannot be used to support other cables. Lastly, the missing box cover is a violation of Sec. 314.25.
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.