National Electrical Installation Standards

Standards as High as Your Own

Monday, December 9, 2019


Charlie and Friends,

Thank you for this wonderful resource and the continued support to the industry.  I read the CQD everyday and get a lot out of the questions and interpretations provided.

This response is in regard to the question where the hot and cold water piping was being replaced with PEX and what to do with the grounding electrode conductors from the service.  I would have to assume that the PEX replacement is just on the interior piping so it is unknown if the supply water line is still metal or not meeting 250.52(A)(1).   As the answer stated, if the water supply is still a valid electrode as described then reconnection of the grounding electrode conductor to some point on the metal water pipe up to 5 feet from the entry to the building is still required.  This may mean replacing or extending the existing grounding electrode conductor.  If extended then the splice would have to comply with 250.64(C).

I believe a good addition the answer given would be to mention 250.53(D)(2) where an additional supplemental electrode is required and that grounding electrode conductor installed to be independent of the metal water pipe.

Keep up the good work and look forward to the question and answer everyday.

Chuck Mello


Hey Chuck thanks for your comments and the kind words. You add some good information. If the grounding electrode conductor needs to be spliced (extended) then the splices must be irreversible compression type that are listed as grounding and bonding equipment or be exothermically made as stated in 250.64(C)(1). As you mention a supplemental electrode to the water pipe is required as stated in 250.53(D)(2) but that might not have been the case when the original electrical installation was made. The question didn't mention if any electrical work was being done at this time.

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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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