National Electrical Installation Standards

Standards as High as Your Own

Tuesday, April 21, 2020


Hello, I am working in a lighting distribution on a new building, where I have 5 separate circuits with 10 lights per circuits. Can I run all the circuit using one conduit and using pull boxes to branch to different locations where the lights are.


Frank Hernandez



Hi Frank, thanks for your question. The short answer is yes, you can install those lighting circuits in a single conduit. There are a few things to consider and apply to attain Code compliance. First, the installation would need to meet Section 300.17 and the specific conduit fill requirements in the XXX.22 section of the wiring method chosen for the installation. This section provides a reference to Table 1, Chapter 9 of the Code. Next, there are correction factors that would have to be applied based on the number of current-carrying conductors in the raceway. See Section 310.15. Where the number of current-carrying conductors exceeds three, a correction factor needs to be applied. Once those rules have been satisfied, be sure that the conductors are protected in accordance with their ampacities after the correction factors have been applied. See Section 240.4 and 240.6.

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

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.