National Electrical Installation Standards

Standards as High as Your Own

Monday, November 21, 2022


Hi Charlie, thanks for keeping this great code forum going. My question is regarding transitioning from one wiring method to another. The common field practice is to use a combination of different fittings to achieve the transition. Is this a code violation, because these fittings need to be listed for the transition? Thanks, Tom Harwood.



Tom, your welcome and thank you for participating in the CQD. Using “Homemade” transition fittings creates several problems, the listing being one of them. The AHJ needs a basis on which to approve an installation. Section 300.10 requires electrical cables, raceways, boxes, and fittings to provide effective electrical continuity. When a “Homemade” transition fitting is used, there is no documentation on how the combination of fittings/parts used will perform, making compliance with Section 300.10 difficult. Using listed transition fittings does provide assurance that the fitting has been tested for a certain purpose and will perform a specified function. This listing provides the AHJ a basis to approve the installation. Using “Homemade” fittings has historically been out of necessity, as there were not listed options available. Now we have several manufacturers that make many different types of listed transition fittings.

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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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