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.”


  • ?
    Tuesday, August 21, 2018

    Question:

    Re: CQD answer published Wednesday, August 10, 2018 - Temporary Feeder 2

    Aerial cable such as Triplex, is not listed or labeled by a National Recognized Testing Laboratory (NRTL). It may be used up to the service drop since the NEC does not incorporate that part of the service system owned by the utility. From there on, Listed material must be used unless specifically allowed or sanctioned by other means.

    I've heard of Four-Plex cable that allows for the insulated neutral wire (grounded conductor) to be carried with the messenger cable, normally used for the grounding conductor. However, I've yet to come across this method of wiring being described in the NEC for use.

    Best Regards, Nick Abbatiello

  • ?
    Monday, August 20, 2018

    Question:

    Re: CQD answer published Thursday, August 9, 2018 -Service Equipment

    In response to the new question for Wed August 8th. I have always assumed that if there is a main disconnect, then any service wires on the load side of that disconnect are to be considered a feeder. Then also the main grounding must occur at the service disconnect and not anywhere downstream of that disconnect. If I read the question correctly, then there is a main disconnect/ overcurrent protection at the meter pedestal he is talking about in his question.

    Therefore I would agree with him that a ground neutral and two hot wires are going to the home from the main at the pedestal. I do not see how it can be done any other way unless the ahj has said that the wiring to the home from the pedestal can be considered as though they were a service drop to the home.

    Kenneth Lynes

    A

    Answer:

    Hey Kenneth thanks for your comment. The original question submitter indicated there is a service pedestal supplying a remotely located one family dwelling. The service overcurrent device must be located "at" the service disconnecting means location as stated in 230.91. Service conductors do not extend beyond the service disconnecting means based on the definition of Service Conductors in Article 100. You are correct, the conductors on the load side of the service equipment (from the service pedestal and the one family dwelling) are feeders based on the definition of Feeder in Article 100.

    As we stated using a 120/240 volt single phase 3-wire feeder on the load side of the service is not allowed because both grounded equipment grounding conductors would be connected to it in the single family dwellings - a violation of 250.24(A)(5). An equipment grounding conductor must be run with the grounded and ungrounded conductors to the one family dwelling. Service Drop conductors are overhead and are utility owned based on their definition in Article 100.

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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