In my limited experience inspectors might have slightly different opinion than engineers or simply interpreting things differently. If possible- try to discuss this with the inspection department.
What follows is my opinion only: in case of lightning strike at panel's site EGC will bring charge into the house as the rod at the panels won't be able to fully neutralize it. What is worse is that charge would go through the equipment grounding path along the way before reaching house grounding rod bringing all equipment grounds up to tens of thousands of volts. If I followed recent discussions on the subject correctly two approaches were suggested to address this:
1. bind grounding rods at panel's site, barn and the house with dedicated #6 copper conductor effectively making GES (ground electrode system) and connect EGC to the house ground at single point only - at the house MSP where it is connected now. In case of a strike that #6 wire will conduct the charge between rods leaving EGC out of this. To protect inverters and possibly other equipment it was suggested to use TVSS on all DC and AC wires coming into the barn and the house.
2. consider all 3 sites as separate systems and run only DC & L1, L2 & N wires between them. Inside each site have its own grounding rod and local EGC. This solution requires TVSS installed on all inputs - DC at the barn and L1,L2 & N at the house with as short as possible path to the local grounding rod. As I understand this TVSS together with electric wires between sites would clamp the lightning charge to the ground along its path.
What follows is my opinion only: in case of lightning strike at panel's site EGC will bring charge into the house as the rod at the panels won't be able to fully neutralize it. What is worse is that charge would go through the equipment grounding path along the way before reaching house grounding rod bringing all equipment grounds up to tens of thousands of volts. If I followed recent discussions on the subject correctly two approaches were suggested to address this:
1. bind grounding rods at panel's site, barn and the house with dedicated #6 copper conductor effectively making GES (ground electrode system) and connect EGC to the house ground at single point only - at the house MSP where it is connected now. In case of a strike that #6 wire will conduct the charge between rods leaving EGC out of this. To protect inverters and possibly other equipment it was suggested to use TVSS on all DC and AC wires coming into the barn and the house.
2. consider all 3 sites as separate systems and run only DC & L1, L2 & N wires between them. Inside each site have its own grounding rod and local EGC. This solution requires TVSS installed on all inputs - DC at the barn and L1,L2 & N at the house with as short as possible path to the local grounding rod. As I understand this TVSS together with electric wires between sites would clamp the lightning charge to the ground along its path.
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