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, August 21, 2019


    I need to understand how the main breaker (in this case 1200A) can support by code feeders of 400A, 800A, & 1000A. The question my customer posed to me was how does the main of 800A support what appears to be a total of (400 + 800 + 1000A) 2200A. I understand the breakers are sized to protect the conductor size but I find limited information on how the 1200A main can support the 2200A feeder loads.  

    Rick Gardner
  • ?
    Tuesday, August 20, 2019


    Hi, We are building a medical office in New Jersey and wanted to ask if we need hospital grade wiring. It is a basic care space where only minor procedures and examinations will be performed in this office.

    Thank you. Joseph


    Hey Joseph thanks for your question. Yes. Patient Care Space, as that term is defined in 517.2, must use the wiring methods in 518.13(A) and have insulted equipment grounding conductors in 518.13(B) as stated in 517.13.

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 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 to view or purchase NECA safety products.

CONTACT US: To submit a Code question, subscribe, or unsubscribe from this list, please e-mail: