Code Quiz of Day

Voltage Drop Limitations on Branch Circuits

May 5, 2015

Branch-circuit rating rules are covered in Part II of Article 210.

The recommended maximum total voltage drop on branch-circuit conductors is ____%.

a) 2
b) 3
c) 4
d) 5

See answer and applicable Code reference

The correct answer is: b) 3

Article 210 outlines the requirements for branch circuits. Branch-circuit rating rules are covered in Part II of this Article. As noted in the first sentence of Informational Note No. 4 of Sec. 210.19(A), "Conductors for branch circuits defined in Art. 100, sized to prevent a voltage drop exceeding 3% at the farthest outlet of power, heating, and lighting loads, or combinations of such loads, and where the maximum total voltage drop on both feeders and branch circuits to the farthest outlet does not exceed 5%, provide reasonable efficiency of operation."

About the Author

Mike Holt

Mike Holt is the owner of Mike Holt Enterprises (www.MikeHolt.com), one of the largest electrical publishers in the United States. He earned a master's degree in the Business Administration Program (MBA) from the University of Miami. He earned his reputation as a National Electrical Code (NEC) expert by working his way up through the electrical trade. Formally a construction editor for two different trade publications, Mike started his career as an apprentice electrician and eventually became a master electrician, an electrical inspector, a contractor, and an educator. Mike has taught more than 1,000 classes on 30 different electrical-related subjects — ranging from alarm installations to exam preparation and voltage drop calculations. He continues to produce seminars, videos, books, and online training for the trade as well as contribute monthly Code content to EC&M magazine.