National Electrical Installation Standards

Standards as High as Your Own

Tuesday, March 17, 2020


Hello Code Folks, I'm being told that the color code for a 480Y-277-volt system is Brown, Orange, Yellow, and Gray for the neutral. Is this required by the NEC? I can't seem to find a rule that spells this out. I would appreciate your views on this. Thank you.

Darrin Watkins



Hi Darrin, the NEC does not require those specific colors to be used for the ungrounded conductors and the grounded conductor of a 480Y/277-volt system. What is required by the NEC is identification of the branch circuit and feeder conductors where the premises wiring system has branch circuits supplied from more than one nominal voltage system. Each ungrounded conductor of a branch circuit shall be identified by phase or line and system at all termination, connection, and splice points. Section 210.5(C) addresses identification for branch circuit conductors and 215.12(C) addresses identification for feeder conductors. Note that specific colors are not specified in either section, but color coding can be used as an option for the identification. The purpose is to differentiate one systems from another. The colors brown, orange, yellow, and gray have been used as a common practice for these systems, just like the colors black, red, blue, and white have been used for 208Y/120-volt systems.

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