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.”


  • ?
    Thursday, March 30, 2017

    Question:

    Sir, I have worked in the field for many years and mostly on doing rewires and new home construction or additions to existing homes. In normal practice here in Minnesota we are normally using romex for the wiring system and all of it now is NMB so it has better ratings than the old NM. My usual practice is to wire completely using plastic boxes for inside outlets and for flush mounted outlets for the outside. If that is not possible (in doing old work or adding an outlet for outside) then a metal box is cut into the outside wall or a surface mount wp box is used. Along with the "in use cover" required on almost all outside outlets now days, we are also required to use a GFI or receptacle rated for damp locations. I sometimes try to install the GFI receptacle inside to prevent exposure of an expensive item to the weather at all. But in all cases we are to use a receptacle suited for damp locations.

    The whole issue should be made plain by code experts or at least a paragraph in the code book which states once and for all if romex is ever allowed to be enclosed in pipe of any kind. There seems to be as many answers to that question as there are inspectors and code experts.

    Ken Lynes

  • ?
    Wednesday, March 29, 2017

    Question:

    Re: CQD answer published Wednesday, March 22, 2017 - Equipotential Bonding

    This is pertaining to the question on attaching the equipotential bond to the service panel. In a situation where you lose the service neutral and your pool equipment and everything associated with it is attached, how will it be determined that the neutral doesn't exist?

    Eric Samek

    A

    Answer:

    Hey Eric thanks for your follow up question. If a service neutral connection becomes disconnected usually it will be very evident by malfunctioning equipment. Line to neutral connected loads become connected in series across the line to line voltage. The path back to the utility transformer using only the earth has much higher impedance that the neutral conductor. Other paths can also exist, such as metal piping systems that are interconnected between more than one service supplied building or structure.

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.

NECA STANDARDS: NECA publishes the National Electrical Installation Standards™ (NEIS™), a series of ANSI-approved performance and quality standards for electrical construction. Visit NECA-NEIS.org for more information. NEISÔ can be purchased in three formats: as paper books, on CD, or as electronic downloads.

NECA SAFETY PRODUCTS: NECA publishes valuable electrical safety books and CDs for the industry. Visit necanet.org/store to view or purchase NECA safety products.

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