Issue with Ufer Grounding

[jaggedben]

This is actually bugging me a little bit. This very rarely comes up in discussion in my work, it's generally a given that the point of connection to a "Metal Underground Water Pipe" per 250.52(A)(1) shall be made within 5 feet of the point of entrance to the building, but is that actually what the code says?

...

Yeah I've argued elsewhere on this forum that that is not actually exactly what it says. But you do need to bond metal water pipes.

 

[NEC Inspector]

This is actually bugging me a little bit. This very rarely comes up in discussion in my work, it's generally a given that the point of connection to a "Metal Underground Water Pipe" per 250.52(A)(1) shall be made within 5 feet of the point of entrance to the building, but is that actually what the code says?

250.50 tells us that all qualifying electrodes described in 250.52(A)(1) through (A)(7) shall be connected to create the Grounding Electrode System. All good there.

250.53 says that if a water pipe is used as an electrode it shall have "Continuity" and a "Supplemental Electrode" is required. Okay, no problem. In the case of the OP's example, a CEE could be that supplemental electrode. Good so far?

250.53(D)(2) includes an exception that the supplemental electrode can be connected per 250.68(C)(1).

250.68 covers connections to Grounding Electrodes. It states that the GEC shall connect to the electrode per (A)-(C). 250.68(C) says that GEC’s and bonding jumpers “shall be permitted to be connected at the following locations and used to extend the connection to an electrode(s):
(1) Interior metal water piping that is electrically continuous with a metal underground water pipe electrode and is located not more than 1.52 m (5 ft) from the point of entrance to the building shall be permitted to extend the connection to an electrode(s). Interior metal water piping located more than 1.52 m (5 ft) from the point of entrance to the building shall not be used as a conductor to interconnect electrodes of the grounding electrode system.”

Is that really saying they must connect to that electrode at that point, or is this only addressing the supplemental electrode connection? Is the “5-foot” rule present somewhere else that I’m missing?

Thanks.

Section 250.68 is for all GEC's or bonding jumper between electrodes. 250.53 is just saying to treat the supplemental electrode conductor the same way you would treat any other GEC or bonding jumper between electrodes.

The "electrode" portion of the water pipe is only that section which is in direct contact with the earth. The code tells you to bond the electrodes themselves together in 250.50, which would technically mean that you would have to run a wire to the portion of pipe that is in direct contact with the earth. Since that is usually a less practical solution, the code then clarifies in 250.68 that you could instead bond to piping that is connected to the electrode, as long as the section of pipe connected to the electrode is less than 5' long. So, you could bond to the electrode itself outside underground somewhere with a proper fitting, or inside within 5' of the wall.

In this case, if practical, I might trench a wire to the pipe location and bond to the pipe underground outside the house. No finishes get messed up, and no one will destroy that electrode until the pipe is replaced with plastic anyway.

One other solution that I believe is technically legal in this case would be to dig up the water pipe, replace a section within 10' of the building with PEX, and thereby eliminate the electrode. Frowned on, but appears to be legal per NEC.

 

[tortuga]

In older versions of the code the entire metal water pipe system was allowed to be used as a conductor.
So a landline phone provider could bond their protector wire from the DMARC to say a hose bib on one side of the house even if the GEC is on another. CATV was also bonded this way.

 

[jaggedben]

In older versions of the code the entire metal water pipe system was allowed to be used as a conductor.
So a landline phone provider could bond their protector wire from the DMARC to say a hose bib on one side of the house even if the GEC is on another. CATV was also bonded this way.

Arguably the code is still ambiguous as to where the water pipe as electrode ends. I think the language describing it has not been updated since the period you allude to.