NEC 250.53 (A)(3) Informational Note Question

[Gunnar]

Hi folks,

I recently was at an older home where the electrical serivce had been moved from its original overhead location on the left side of the house to an underground service at the right side. In this case, a new service equipment with a single main disconnect was placed at the right side and fed to a new panel that replaced the original service equipment at the left side. A new ground rod was driven near the new service and bonded to the original ground rod near the replacement (sub) panel with a #6 conductor. The distance between the two rods got me to thinking (dangerous, I know).

NEC 250.53 (A)(3) in general requires two rods placed a minimum of 6 feet apart and the Informational Note says that twice the distance of the longest rod is better (but not required). I cannot find a maximum limit in distance for the two rods and began wondering if there would be some kind of issue given the length of the #6 conductor and the potential resistance that would occur over that (estimated) 80+ foot distance? I realize that this should not normally carry any voltage/current, but in the (unlikely) event of a lightning strike, would that contribute to failure of the conductor? What if that distance were greater, like 200 feet?

This is essentially a four-part question:
1) Does anyone know of a maximum distance for the two rods (electrodes, whatever)?
2) The IN talks about the increase in "paralleling efficiency". Would that efficiency drop if the rods were placed even farther apart? (I wouldn't think so, but...)
2) Should that #6 conductor have been increased to #4 (or greater) to address potential distance/resistance/voltage drop?
3) Am I overthinking this and should I just go read a good book?

Thanks

 

[infinity]

1-None
2-I don't think so
3-No, the #6 is the maximum required because any larger is a waste of money.
4-Many here have opined that ground rods have a limited value.

 

[tortuga]

When a utility converts an overhead service to underground, or electrical contractor (EC) relocates the service, it’s common for one or more communications services (CATV, telephone, etc.) to remain at the old location. In these cases, the EC may leave the original ground rod in place and bond to it, to comply with requirements on communications protector grounding. As the old protectors bond there also.
800.100 imposes limits on the bonding conductor or grounding electrode to the communications protectors.
If a new service is more than 20 feet from the existing say a CATV or POTS drop you'll typically see the old electrode left and bonded to the new system.
When a grounding electrode systems is replaced you want to see all the existing communications protectors bonded to the new system so that EC probably did a good thing there.