National Electrical Installation Standards

Standards as High as Your Own

The National Electrical Code is the bedrock of the electrical construction business.

Do you know all the ins and outs of the Code? NECA and Electrical Contractor magazine are pleased to present their daily online feature, “Code Question of the Day,” Sponsored by Eaton.

  • ?
    Wednesday, September 18, 2019


    NEC Article 350.30 (A) Exception No. 4, states following: “Lengths not exceeding 1.8 m (6 ft) from the last point where the raceway is securely fastened for connections within an accessible ceiling to luminaire(s) or other equipment. For the purposes of 350.30, listed LFMC fittings shall be permitted as a means of securement and support.” 1. I am looking for last sentence clarification “For the purposes of 350.30, listed LFMC fittings shall be permitted as a means of securement and support.” Is this only applicable to Exception 4 for the ceiling luminaries or is it applicable for entire 350.30 (A) and (B) article? 2. Exception 4 allows LFMC fittings as means of securement and support. Do the fittings have to be specifically listed for LFMC support or can they just be listed for use with LFMC?

    Thanks Chris
  • ?
    Tuesday, September 17, 2019


    What is the difference between Article 376.23(A) and 376.23(B)?  What is an example or application of 376.23(A)?

    Thank you for this forum, Paul


    Hey Paul thanks for your question and you are welcome. Metal wireways are raceways as defined in 376.2 and are often used for multiple circuit conductor installations that are many feet in length. The title of 376.23 indicates the rule is for insulated conductors so it is about avoiding damaging conductor insulations during their installation.

    If insulated conductors are pulled into the ends of metal wireways then the rules in 376.22 are used to size the metal wireway. If the conductors are pulled in at other than the ends, or if the wireway has an elbow that changes the wireway direction more than 30 degrees, the "width" of the wireway at that point must be at least that of Table 312.6(A) as stated in 376.23(A). For example, this applies if a cable entry or raceway is connected to the side of the metal wireway.

    It is becoming more common to use short sections of metal wireways in place of a pull box. The dimensions of metal wireways used that way need to be at least that of 314.28(A) - typically 6 times (for angle pulls) or 8 times (for straight pulls) the raceway size.

ABOUT CQD: NECA’s Code Question of the Day (CQD) is a leading National Electrical Code® forum for NECA and the industry. The CQD generates a lively dialogue and relative practical and Code-based responses to an ever-increasing and interactive audience.

IMPORTANT NOTICE: All answers are based on the latest edition of the National Electrical Code®, unless the question requests a response based on a specific edition. This correspondence is not a formal interpretation of the NEC®. Any responses expressed to the questions are opinions and do not necessarily represent the official position of NECA, NFPA, or any technical committee. In addition, this correspondence is neither intended, nor should it be relied upon, to provide professional consultation or services.

ABOUT CHARLIE: 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. Charlie was also a member of NECA’s Academy of Electrical Contracting. Charlie’s experienced team of industry experts keep the CQD dialogue and discussions active and informative in the spirit of the man himself, as he wanted.

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