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Thursday, November 23, 2023

Question:

Hello Charlie, I am trying to find out if it is acceptable to use a rectangular wall box in the ceiling. I know the ceiling box is supposed to accept 8/32 screws. Is the wall box volume smaller than a ceiling box? Is there a certain amount of space I should have free in the ceiling mounted box? Thanks, Ronald Detmer

A

Answer:

Hi Ronald, the volume of the box is determined by Section 314.16(A)-(B), based on how many conductors/devices will be installed in the box, regardless of whether the box is installed in the ceiling or wall. The type of box used in a wall or ceiling will depend on:

  1. The manufacturer’s installation instructions/listing of that box; AND
  2. What if any utilization equipment will be served by that box.

Sections 314.23 and 314.27 provide guidance on the support requirements for boxes and boxes supporting luminaires.

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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.

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