National Electrical Installation Standards

Standards as High as Your Own

 
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Friday, December 1, 2023

Question:

Hi Charlie, I can't start my day without checking in on the Code Question of the Day. My question is clarification for the routing of Service Entrance conductors. Specifically, when a whole house transfer switch is installed, which also serves as the service disconnect. I have seen the service conductors routed through the existing panel and then through a short piece of PVC to the new service disconnect/transfer switch. Then a separate PVC is used to bring the main power feeder back to the existing panel and connect to the main feeder breaker to supply what will now be the Sub-Panel for the entire house. Section 230.7 indicates that service conductors can't be installed in same "raceway" with other conductors but doesn't recognize the gutter area of a panel as a raceway (as explained in the enhanced content area in the NFPA link website).
The installation described above doesn't seem to meet the intent of the code but the actual wording in the code may allow this. What say you, Charlie? Thank you again for your insight on these Code questions, much appreciated! Rick Kinsman
A

Answer:

Hello Rick, thanks for the kind words and participating in the CQD. This poses a great question as the to the intent of 230.7. In the traditional installation the gutter space would accommodate branch-circuit, feeder, and service conductors as they are all terminating in that enclosed panelboard. Since the service conductors are not terminating inside this enclosed panelboard, it could be argued that a violation of 230.7 now exists. Additionally, there may be a manufacturer installation instructions/listing issue as that enclosed panelboard may not be designed for pass though applications.

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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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