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Friday, September 30, 2022

Question:

Dear CQD, thanks for this wonderful learning experience and the free service the CQD provides. Can you explain the intent of Section 312.2 of the 2020 NEC®? More specifically explanations of the methods for meeting the 1/4inch of airspace requirements, and the use of fittings.

Thank You,

Willy Culley II

A

Answer:

Willy, thanks for the kind words, and glad to hear that you enjoy the CQD. Section 312.2 requires enclosures installed in damp or wet locations shall be placed as to prevent moisture or water from entering and accumulating within the cabinet. It also requires a 1/4" of air space between the enclosure and the wall or surface it is mounted to. Many manufacturers will build enclosures with convex mounting holes that protrude out far enough to achieve the 1/4" of air space required by this code section. Section 312.2 also mandates the use of fittings listed for wet locations, when a raceway or cable enters an enclosure above live parts. Not all gasketed fittings are listed for this purpose, it is always advisable to consult with the manufacturer if you are unsure. 

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.

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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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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. 

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