Ecmweb 16303 9 21 17wwhweb
Ecmweb 16303 9 21 17wwhweb
Ecmweb 16303 9 21 17wwhweb
Ecmweb 16303 9 21 17wwhweb
Ecmweb 16303 9 21 17wwhweb

What’s Wrong Here? Hint: A Terrible Tap

Sept. 21, 2017
Think you know how this installation violates the NEC?

Hint: A terrible tap

Scroll Down to See the Answer

This was a terrible attempt to tap power from this 800A circuit breaker. The installer simply took a 12 AWG wire and shoved it into the same terminal with the 350kcmil conductor. This created a very poor connection, which resulted in some arcing and sparking. The heat from this arcing ultimately damaged this 800A breaker to the point where it needed to be replaced because the terminals were so badly damaged. The conductors were also damaged. Thankfully, this did not start a fire.

Jamming two conductors into a terminal designed for only one is a violation of Sec. 110.14(A) and can result in damaged equipment, or even worse. There is one open terminal remaining for each pole of the breaker, but the terminal is much too big to accommodate the 12 AWG wire. If this installer was trying to make a feeder tap, there are splicing devices that could have been used to make a connection directly onto the conductors instead of jamming wires into the terminals. Of course, the installer could have put the 12 AWG wires on their own breaker 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.

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