Joe Penachio

Hello KC, try this.
Making this connection would make the pool grid part of the grounding electrode system.
Since this grid is not listed as a grounding electrde as per 250.52(A)(1)-(A)(8), it is not even permitted to be connected to the grounding electrode system per code.
It would not meet (A)(6) because it is not listed, and it would not meet (A)(8) because it is not a piping system, underground tank, or underground metal well casing

thekctermite

Thanks Joe. That's a code section I've been eyeballing pretty hard. I think they could make a somewhat solid case for 250.52 (A)(3) (concrete-encased electrode) if they were using a #4 or larger wire. They've specified a #6 though.

I've spoken with the architect about my concerns, and spent some time expaining the difference between grounding systems and bonding grids, and why I feel there's an issue with connecting the two in this manner. I think they're trying to go above and beyond the code's bonding requirement by doing this, but lack the fundamental understanding of what the bonding grid does. We'll see what plays out.

Joe Penachio

I wouldn't consider the slab as a concrete encased electrode because a concrete encased electrode is " located horizontally near the bottom or vertically and within that portion of a concrete foundation or footing " etc. with 20' of 1/2" rebaar or 20' of # 4 Cu.