What’s Wrong Here? Hint: It’s Time to Read the Grounding Rules, Again!

Jan. 16, 2020

Think you know how this installation violates the NEC? Hint: It’s time to read the grounding rules, again!

Hint: It’s time to read the grounding rules, again!

Whomever installed this time clock apparently does not take grounding and bonding rules too seriously. If the installer had followed the instructions for this equipment, the equipment grounding conductors would have been connected to the green, hexagonal head, grounding screw on the time clock body, instead of wrapping them around one of the enclosure’s mounting screws.

Section 250.8(A) provides installers with eight options for connecting equipment grounding and bonding conductors. Listed pressure connectors and pressure connectors specifically listed for grounding and bonding can be used. Section 250.8(A) also permits the use of terminal bars, exothermic welding, machine screw fasteners engaging at least two threads or secured with nuts, thread-forming machine screws engaging at least two threads, connections part of a listed assembly or other listed means. Using a sheet metal mounting screw for the double purpose of connecting the equipment grounding conductors is not permitted.

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.