What’s Wrong Here? Hint: Pigtail Problem
Hint: Pigtail problem.
I spotted what I am assuming to be a partially completed installation and asked myself, where’s the “pigtail” connection from the green equipment grounding conductor splices to the metal box? The metal jacket of these interlocked metal-tape-type MC cables does not provide an effective ground-fault current path as described in Sec. 250.118(10) and cannot be used by itself for bonding and grounding of the metal box. The green equipment grounding conductor must also be connected to the metal box. In fact, Sec. 250.148 requires a connection used for no other purpose to be made between the metal box and the equipment grounding conductor(s). The equipment bonding jumper or equipment grounding conductor must be sized from Table 250.122 based on the largest OCPD protecting circuit conductors in the box. Perhaps once this installation is completed the installer will make sure to install that pigtail connection for the EGC and also install a box cover or whatever equipment might be getting installed here.
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.