National Electrical Installation Standards

Standards as High as Your Own

Wednesday, March 8, 2023


Hi Charlie, thanks for this forum. Does the smoke evacuation system for a theater get connected to the emergency electrical system? It makes sense to wire the smoke control system to the emergency power, but we are being told this incorrect. I cannot find any article or code section in the NEC® that specifies this one way or the other. Thanks in advance Phil Adams


Hi Phil, glad to hear you enjoy the CQD. This is another example of where work performed by electricians and electrical contractors has become more complex. As a result, these complex systems are impacted by other Codes in addition to the NEC®. This is also a good example of the importance of ensuring we use the appropriate terminology. Terms like: Emergency Power, Standby Power, Back Up Power, are just some examples terms used universally, but they all have a very different meaning in the Code.

Emergency System (Article 700) – A required system, regulated for reliability and the top of the hierarchy in importance, as it generally includes the electrical loads necessary in aiding the safe and speedy evacuation of people in the building during an emergency.

Legally Required Standby Systems (Article 701) – A required system, second in the hierarchy. It generally supplies electrical loads that help the first responders as they enter a building to provide aid to occupants and/or fight a fire etc.

Optional Standby Power (Article 702) – An optional system intended for convenience type loads that do not qualify as an Emergency Loads or Legally Required Standby Loads.

Article 700 of the NEC® covers installation of the wiring related to the emergency system. The actual loads connected to an emergency system are generally specified in Chapter 27 of the International Building Code (IBC®).  Section 2702.2 establishes where Emergency Systems and Standby Systems are required. Section 2702.2.17 states “Standby Power shall be provided for Smoke Control Systems as required in Sections 404.7, 909.11, 909.20.7.2 and 909.21.5.

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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