National Electrical Installation Standards

Standards as High as Your Own

Friday, March 2, 2018


Charlie, Thank you for all of your great work to help the electrical industry.

My question concerns a 60 amp, three pole, four wire power receptacle that has been factory built into a fused disconnect switch. Typically, these receptacles and switches are rated at 600V.  Am I prohibited from using one of these receptacle / fused disconnect assemblies in a 240V, three pole, four wire application?

Thank you, Robert Frye, PE



Hey Robert thanks for your question and the compliment. Electrical equipment must be rated for at least the nominal circuit voltage as stated in 110.4. Receptacles connected to circuits with different characterizes (such as different nominal voltages) must be designed to be noninterchangeable, on the same premises as stated in 406.4(F). So unless the listing instructions prohibit it and you are not using the same receptacle configuration for a different voltage the 600 volt switch/receptacle combination is allowed to be used for a 240 volt application.

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ABOUT CHARLIE: 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. Charlie was also a member of NECA’s Academy of Electrical Contracting. Charlie’s experienced team of industry experts keep the CQD dialogue and discussions active and informative in the spirit of the man himself, as he wanted.

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