Hi all. I have a question about a grounding conductor to a subpanel. I have a project where I want to replace an existing 800 amp 480/277V subpanel in a building that is currently fed from the building service via (2) 4" buried conduits with (4) 750 MCM in each. I cannot see where any ground conductor has been installed in the raceways. Question is, how do I get a ground conductor to the subpanel, as the existing feeder is 300-400 feet long approximately, routes under a wing of the building, and has no pull boxes? Can I provide a ground via another route from the main to the subpanel, or will I cause an issue because the ground is not with the parallel feeder? I believe I could physically route a ground in a conduit from the service to the subpanel through the building. Thanks