CQD: 9/18/2014

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Wednesday, September 17, 2014

Question:

Hello Charlie,

Thank you for the CQD, it was invaluable during my NEC coursework.

One of our clients is requesting for us to install a 3/16” lexan cover over lugs and fuses within various electrical equipment (e.g.: Fused Disconnects). The particular brand of disconnect we are working on has a touch-safe shield over the line side, but the fuses and lugs are exposed. They are requesting a hinged cover over load side of the disconnect and fuses. My question is, “Does it violate the code to install non UL listed components into a UL listed devise?”

Thank you, Kevin Norris

Answer:

Hey Kevin thanks for your question and the compliment. The NEC does not specifically prohibit modifying equipment. But the manufacturer's instructions might and if so that would be a requirement as stated in 110.3(B). Additionally modifying any manufactured equipment changes what they designed or possibly how they intended the equipment to function. It is no longer the same as when it was evaluated as part of the listing. Even well intended changes such as additional guarding of live parts can sometimes create other problems. The specific decision is left to the AHJ to determine if they can approve the installation. There are listed products available that have "finger safe" rated fuses and their terminations.

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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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