National Electrical Installation Standards

Standards as High as Your Own

Tuesday, December 17, 2019


Re: CQD answers published November 28 and December 10, 2019 -Water Piping Replacement

Electrode retrofitting replacement is not in the NEC that I know of, but since so many inspectors read this excellent CQD, I will offer up my solution for losing the metal main water supply line. It details Chuck Mello's mention of a 250.53(D)(2) supplemental electrode.

The replacement of the water supply line essentially always requires that a trench be dug.  At this time it is very easy to install a supplemental electrode system [250.53(D)(2)]. Place a bare copper conductor in the trench with the new plastic pipe, with at least one but preferably two ground rods [250.52(5) & 250.53(A)(3) & 250.53(B)].  These rods are also driven in the trench, then use direct burial conductor clamps. This creates a "permanent" retrofitted electrode which is not easily damaged. Bare #6 copper would be allowed, but I used 25+ feet of  #2, more in compliance with 250.52(A)(4) - an extra $20 cost - and put the rods 20' apart.

Scott Cline


Hey Scott thanks for your follow up comment and the kind words. You have a good suggestion for solving a problem that is worth sharing, if building water supply piping is replaced. But as the original question stated the cold and hot water lines were being replaced, nothing was mentioned about replacing the water supply piping to the building or if any electrical work was being done.

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