National Electrical Installation Standards

Standards as High as Your Own

?
Thursday, November 2, 2017

Question:

In definitions of 517 for “Essential Electrical System” and “Critical Branch” and “Life Safety Branch” it is clear that parts of these systems include Feeders and Branch circuits. In my mind I see this not only from the service disconnecting means bout also from the alternate source of power ie: generator. In section 517.30(C)(3) under “Mechanical Protection…”. In number (1) of this section if PVC is used Schedule 80 is required. In Number 2 of this section if schedule 40 PVC is used it shall be encased in 2” of concrete.

Q- Would this requirement be from the alternate source ie: Generator all the way to the building (ie: underground installation) / the branch circuit Panel Board?

Thanks

Lukas Koomen

A

Answer:

Hey Lukas thanks for your question. The rules for mechanical protection of the essential electrical system wiring are now in 517.31(C)((3)  in the 2017 NEC. Yes, this rule applies to all the wiring regardless of its location to its source.

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.

 CONTACT US: To submit a Code question, subscribe, or unsubscribe from this list, please e-mail: codequestion@necanet.org.