I have a situation that I would like clarity on because I don't know what to do. Here is the situation. I have a house with a 200Amp service. I am adding a garage that is physically attached to the house, but is electrically isolated from the house. The service panel attached to the house is being increased to 400 Amp service. The 400Amp panel is divided into 2 -200 Amp with disconnects for each in the panel. The 400Amp service panel is grounded, and the ground conductor from the 400amp service is bonded to this ground. Everything is correct as far as separation of the disconnects etc. One of the 200 Amp 4 wire (A/B/N/G) lines goes into the house, and the other 200 amp 4 wire (4-4-4-3 A/B/N/G) is routed through a 200ft underground conduit to a breaker panel in the other building. The original failed setup, the inspector said that the garage slab bonding rod needed to be connected to the ground equipment conductor. so the electrician put a bonding wire from the slab to the ground equipment conductor at the garage panel. This was inspected and failed, not due to the slab being insulated from the earth which is is due to a moisture barrier, but because the inspector wanted another separate bare wire run from the slab back to the 400amp service panel. Since it is not possible to run that wire through the already packed conduit, he said we needed to run a 270ft long wire from the slab ground around the outside of the garage to the 400 Amp service. Im not going to poison this thread with my opinions. Can someone explain why i am being asked to put another wire from the slab ground to the 400Amp service when there is already a ground conductor and a ground equipment conductor running through the conduit. I can provide pictures and connection diagrams at request. I would not usually reach out for assistance like this, but when the electrician or I try to talk to the inspector he just keeps saying that we are not in compliance with the NEC and either hangs up on us, or in the case where i went down to the county inspectors office, he refused to discuss the setup with me because I am the homeowner and not the electrician... which he hung up on.
