I had a well pump installed and in the process discovered the significance of tying all metal surfaces together by EGCs to provide a path back to neutral.
Diagram is attached for reference.
The neutrals and grounds throughout all subpanels are bonded. There is a single ground rod tied into neutral bar at utility pole.
There is no ground wire in the system - equipment and appliances are simply "grounded" through their neutral wire.
Much of this can be rewired, or a separate ground wire added. What won't happen is a ground wire running from the point of first disconnect (utility pole) a thousand feet to the farm buildings.
The main line from the pole is spliced(split) to go to two different buildings.
- There is no required electrical code for this rural installation. - -
I'm not 100% clear on this, but it seems one way to retrofit would be to ground and bond to neutral at each of these second disconnects. Then the only danger of losing path of low resistance back to the source would be if the neutral wire from these two second disconnects were to be broken.
And then of course I would isolate ground from neutral for all other subpanels and circuits.