National Electrical Installation Standards

Standards as High as Your Own

?
Tuesday, March 17, 2020

Question:

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

A

Answer:

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.

Happy St. Patrick's Day!

ABOUT CQD: The Code Question of the Day (CQD) is NECA and ELECTRICAL CONTRACTOR Magazine’s flagship National Electrical Code (NEC®) public forum for the industry, sponsored by EATON. The daily distribution of Q&A generates a lively dialogue and shares relative Code-based practical responses.

SUBMIT YOUR CODE QUESTION: Click here to submit a question to for inclusion in an upcoming edition of the Code Question of the Day, or email codequestion@necanet.org

CHARLIE TROUT: Charles M. Trout, better known as Charlie, was a nationally known NEC® expert and author. He served on several NEC® technical committees and is past chairman of CMP-12. In 2006 Charlie was awarded the prestigious Coggeshall Award for outstanding contributions to the electrical contracting industry, codes and standards development, and technical training. Even though Charlie passed away in October of 2015, his work continues in spirit. NECA continues to maintain this question forum for its many subscribers in memory and recognition of all his significant contributions to making the NEC what it is today.

NECA STANDARDS: NECA publishes the National Electrical Installation Standards™ (NEIS™), a series of ANSI-approved performance and quality standards for electrical construction. NEIS can be purchased in the NECA Store in three formats: a printed or PDF download of a standard or, as an annual subscription service.

NECA SAFETY PRODUCTS & PUBLICATIONS: NECA produces electrical safety publications and products for the industry including jobsite safety guides, handbooks and resource kits. View a full listing of available resources and products »

IMPORTANT NOTICE: Unless the question requests a response based on a specific edition, all answers are based on the latest edition of NFPA 70® National Electrical Code®.

This correspondence is not a formal interpretation of the NEC® and any responses expressed to the questions are opinions and do not necessarily represent the official position of NECA, NFPA, the NEC Correlating Committee any Code-making panel or other electrical technical committee. In addition, this correspondence is neither intended, nor should it be relied upon, to provide professional consultation or services. 

UPDATE YOUR SUBSCRIPTION PREFERENCES: Subscribe or Unsubscribe from this list.