Q. How many neutral wires can I install on a single terminal in a panelboard?
A. According to 408.41, each neutral conductor within a panelboard must terminate to an individual terminal. What's the thinking behind this rule? If two neutral conductors are connected to the same terminal, and someone removes one of them, the other neutral conductor might unintentionally be removed as well. If that happens to the neutral conductor of a multiwire circuit, it can result in excessive line-to-neutral voltage for one of the circuits, as well as undervoltage for the other circuit. See 300.13(B) for details.
This requirement doesn't apply to equipment grounding conductors because the voltage of a circuit is not affected if an equipment grounding conductor is accidentally removed.
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.