National Electrical Installation Standards

Standards as High as Your Own

?
Friday, April 27, 2018

Question:

I have a project that I am currently working on that requires the replacement of 15 KVA primary transformers. Upon research of the existing transformers and branch I ran across a transformer that feeds a bank of disconnect switches. The secondary side of the disconnect switches then feed back into the secondary section of the transformer and out to their specified load in underground conduit.  “see attached email with pictures of existing and notes from plans”

Can the secondary section of the transformer be used as a wireway?

Thank You, Roger Schmidt

A

Answer:

Hey Roger thanks for your question. We were not able to view the pictures and notes and also are wondering if you meant 15 KV primary transformers especially because you mentioned separate secondary section. Possible concerns can be restricting ventilation and having sufficient space for the additional conductors. But Article 450 does not specifically prohibit conductors from being routed back through a transformer enclosure to supply other equipment.

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.