We have a customer requesting FOP. the site already existing and constructed. When doing a FOP test which ground rod is used to start your test. I can understand if the site was a new construction and raw land. the site already has grounds and ground rod in place. which ground rod already 3 foot deep would be the best to use. Or just install new ground rods. Sorry first time doing FOP so im still not comfortable doing test. I think we would everntually sub out to contractor but i still want o know the process. I can figure it out for raw land but the existing construction is my problem.