National Electrical Installation Standards

Standards as High as Your Own
 
Menu

NECA Online Help Desk
Please leave a message
Submit your Code Question | Subscribe to CQD | Un-Subscribe To CQD | Print | Share This | RSS
?
Tuesday, May 9, 2017

Question:

Hello Charlie,

There is a situation that my Electrical Supervisor and crew found where a metal clad cable was installed in a 4" PVC conduit run, along with both 120/208V feeders and 277/480V lighting branch circuits. The reason the MC cable was installed, I believe, was to provide separation for an emergency circuit. Under 330.10, (A), (7) the NEC states MC cable can be installed in any raceway. Three and a half years after this installation was complete we experienced a short between the feeder conductors and the lighting branch circuit where the insulation was damaged. I believe the cause of the damage was pulling the MC cable in the conduit with the other conductors.

My question is: Can you find anything in what I described that may be a code violation?

Sincerely, Gary

A

Answer:

Hey Gary thanks for your question. Wiring from an emergency source must be kept entirely independent of all other wiring as stated in 700.10(B).

A similar insulation damage problem could occur with non-emergency wiring. The second paragraph of the .22 section in many of the raceway articles also has wording that allows cables to be installed. Consider submitting a Public Input for the 2020 NEC to not allow cables (maybe just metal armored cables) in raceways with other conductors at www.nfpa.org/70next. You have until September 7 of this year.

ABOUT CQD: The Code Question of the Day (CQD) is NECA and ELECTRICAL CONTRACTOR Magazine’s flagship National Electrical Code (NEC®) public forum for the industry, sponsored by EATON. The daily distribution of Q&A generates a lively dialogue and shares relative Code-based practical responses.

SUBMIT YOUR CODE QUESTION: Click here to submit a question to for inclusion in an upcoming edition of the Code Question of the Day, or email codequestion@necanet.org. 

CHARLIE TROUT: 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. Even though Charlie passed away in October of 2015, his work continues in spirit. NECA continues to maintain this question forum for its many subscribers in memory and recognition of all his significant contributions to making the NEC what it is today.

NECA STANDARDS: NECA publishes the National Electrical Installation Standards™ (NEIS™), a series of ANSI-approved performance and quality standards for electrical construction. NEIS can be purchased in the NECA Store in three formats: a printed or  PDF download of a standard or, as an  annual subscription service.

NECA SAFETY PRODUCTS & PUBLICATIONS: NECA produces electrical safety publications and products for the industry including jobsite safety guides, handbooks and resource kits. View a full listing of available resources and products »

IMPORTANT NOTICE: Unless the question requests a response based on a specific edition, all answers are based on the latest edition of NFPA 70® National Electrical Code®.

This correspondence is not a formal interpretation of the NEC® and any responses expressed to the questions are opinions and do not necessarily represent the official position of NECA, NFPA, the NEC Correlating Committee any Code-making panel or other electrical technical committee. In addition, this correspondence is neither intended, nor should it be relied upon, to provide professional consultation or services. 

UPDATE YOUR SUBSCRIPTION PREFERENCES: Subscribe or Unsubscribe from this list.

Submit your Code Question | Subscribe to CQD | Un-Subscribe To CQD | Print | Share This | RSS

© 1999 – 2014 National Electrical Installation Standards. All rights reserved.
Brought to you by NECA. NECA is the voice of the electrical contracting industry NATIONAL ELECTRICAL INSTALLATION STANDARDS, NEIS and the NEIS logo are registered trademarks of the National Electrical Contractors Association.

Created by Matrix Group International, Inc.

Follow Us on: