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
?
Monday, June 5, 2023

Question:

Good morning, Charlie. Seeing the code question of the day every morning is always a nice way to get into the technical mindset. Anyhow, here's the question: For an installation of high current rated cable, is there a direct callout in the code for bending radius operating at a nominal voltage under 1000VAC?

 

We are installing a service with parallel (2 sets) of 500kcmil at 480V and things are getting a bit tight. I decided that my minimum is 14" based on Table 312.6(A), but that's not what that table is used for. I've oversized the enclosures to account for needed space, but knowing a minimum bending radius would be excellent. Thanks, Jeremy Dyer
A

Answer:

Hello Jeremy, glad to hear you enjoy starting your day with the CQD. The 2017 NEC® does not specify a minimum single conductor bending radius for installations under 1000V. However, Tables 312.6(A) and 312.6(B) of the NEC® specify the minimum required gutter space for enclosures, ensuring there is adequate room for the installation of conductors on to the appropriate terminals. The manufacturer’s installation instructions may also provide minimum bending radius for their conductors. Section 300.34 does provide guidance on conductor bending radius for installations over 1000V

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: