National Electrical Installation Standards

Standards as High as Your Own

 
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Friday, August 25, 2023

Question:

Hi CQD, I have a steam shower in an individual dwelling unit. The nameplate shows the unit FLA as 42A. Manufacturer says we need to use #8AWG copper conductor. Is this correct? Thanks, Michael Birckhead
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Answer:

Hello Michael, great question! With the information you provided a #8 AWG copper conductor may not be large enough for a 42A load. Depending on the temperature rating of the terminations/lugs and Table 310.16, a #8 AWG copper conductor has an ampacity anywhere from 40A to 55A. In this case the conductor should be sized to whichever is more restrictive, the NEC® or the manufacturer’s installation instructions, but in no case smaller than a #8 AWG copper conductor to maintain compliance with the installation instructions and listing of the equipment.   

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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®.

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