Am I right to think 250.64(C)(1) applies only to a single GEC and say, for example, splice onto it in order to extend it?
Why the junction boxes?
If my math is correct, I need a #2 Common GEC, which is larger than #4 and would require protection from physical damage according to 250.64(B)
It sounds like your advocating for using a GEC tap with the #8, but you say a single #8. I don't think panels #1 and #2 could share the same tap.
using the water system as a ground is not a good idea, bonding a water system is to protect the water system from becoming energized, not to be used as a path to earth ground for the purpose of diverting a fault current from an electrical system, I would attach the earth ground of each 100 A panel from the grounding electrodes and make the #4 continuous, uncut, I know its a hassle but uncut is the best practice if possible.
Well, underground water piping is a code approved electrode... and in my 10 years + in the field as a residential electrician, we've always done one GEC to the street side of the water main and another at the meter to two ground rods. Are there other code approved methods? Absolutely. But this is common practice in my experience. To your point, I actually just stumbled upon a comment by Mike Holt that the water utility doesn't like this practice, which is news to me, but it's NEC approved nonetheless.
Uncut is not just best practice, it's required for the GEC unless you use exothermic welding or irreversible connections.
I mean a grounding bus bar would essentially be the same set up - a common GEC and taps to each panel, but it would cost more than a couple split bolts.
I hear you and appreciate the feedback. Your point is not invalid, but I wouldn't call a couple junctions boxes making this "FAR more complicated than it needs to be." Something about a split bolt resting in the main panel just seems sloppy to me, hell the split-bolt in a j-box still seems sloppy to me, I would prefer a nice C-tap but don't have the tools required.
Huh? #4 and larger only require protection when "exposed to physical damage".
I wouldn't put the split bolts in the panels, do it outside the panels.
I'm with this method. Drop two ground rods, run continuously to the furthest panel from the rods, then, tap off to the two panels in between. #4 solid so no need for any protection unless the environment or conditions require. Least amount of wire. 2 pink c-taps for the jumpers. Legal.
The way I've learned and the way I understand the 2 methods mentioned is that yes we bond the water system typically within the 1st 10' of were the water main enters the structure , I usually put it on the load side of the water meter for inspection purposes, again that bond is specifically for stray or fault current to find its way back to the grounding rods which is the true fault current bleed off.
Grounding electrodes have 2 functions that I am aware of
Not sure what this argument was ..
That does sound pretty scientific, but probably not.
Sorry, but that's incorrect. The supply neutral is the fault-current pathway that assures protection activation.
what if the surge coming in to ones service drop is rushing toward the home, it seems at that point the utility return is alittle late
