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Monday's Question: Hello CQD, I have an 1 1/2 inch EMT with multiple branch circuits. can you run one oversized ground wire for all branch circuits and attach it to a ground bar in the 12x12 box that all the circuits run into.
Monday's Answer: Hello Daniel, A single equipment grounding conductor can be installed with multiple circuits in the same single run of electrical metallic tubing (EMT). Section 250.118 recognizes that the EMT by itself can serve as the required equipment grounding conductor. An installed single equipment grounding conductor must be sized based on the rating of the overcurrent protective device ahead of the largest branch circuit in the run. See Section 250.122(C). Connecting the equipment grounding conductors together and to the box using an equipment grounding terminal bars one way of complying and this is covered in Section 250.148.
Thanks for the additional comment on the response for the 08-03-2021 question and answer. The Code Question of the Day provides responses based on what is included as minimum requirements of the National Electrical Code. Your comment is a good one and provides a reminder for readers that there certainly could be local code requirements that are more restrictive than the minimum rules in the NEC. In those cases, legally adopted local electrical code rules would be applicable.
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