National Electrical Installation Standards

Standards as High as Your Own

 
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Monday, February 20, 2023

Question:

Good day and thank you for providing us out in the field with great information. I was in a newly constructed house in Arizona to replace existing single and 3-way switches with compatible dimmer switches. The grounds from the NM cables were crimped together in the plastic boxes. However, there were no equipment grounding wires connected to any of the switches. I even found a fan speed control that had the attached equipment grounding pigtail cut off. I say that any device, even in a nonmetallic box, should have the yoke bonded. Is there a code section that references this?  Thanks, Tom Ercole
A

Answer:

Hi Tom, your welcome, and glad to hear you are enjoying the CQD. Section 250.148(D) requires nonmetallic boxes to provide an equipment grounding conductor arranged so a connection to any fitting or device requiring connection to an equipment grounding conductor, can be made. Additionally, Section 404.9(B) requires snap switches, dimmers, and control switches to be connected to an equipment grounding conductor by one of the methods in Section 404.9(B)(1) & (2). There are 3 Exceptions to 406.9(C) summarized as follows:

  • Exception No. 1 - Applies to replacement switches where an equipment grounding conductor connection is not available, but then a nonmetallic faceplate and screws, or nonmetallic yoke must be used.
  • Exception No. 2 – Listed kit or listed assembly with nonmetallic components.
  • Exception No. 3 – A snap switch with integral nonmetallic enclosure complying with Section 300.15(E).

 Hope this helps.

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