National Electrical Installation Standards

Standards as High as Your Own

Monday, December 27, 2021


Hello Code Question of the Day Staff.

The question today is about exit stairwells in buildings. Can a large feeder (1200 ampere) be installed vertically through a stairwell to get from the basement floor to the roof? The stairwell does seem to be a required egress stairwell. You opinion on this would be very much appreciated.

Clay Smith



Hello Clay,

Thanks for the question. A new rule in the 2020 NEC Section 300.25 addresses your question. It reads as follows: Exit Enclosures (Stair Towers). Where an exit enclosure is required to be separated from the building, only electrical wiring methods serving equipment permitted by the authority having jurisdiction in the enclosure shall be permitted within the exit enclosure. This rule restricts electrical equipment in the exit enclosure other than the electrical equipment and wiring serving that exit enclosure.

Hope this is useful. 

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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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