I have a manufactured home that is going to be 60' away from the service equipment. I need to install a disconnect within 30' of the home. My question is do I need to run 4 wires between the service equipment and the disconnect? I thought there was an exception to only run 3 wires and drive 2 ground rods and then 4 to wires to the home. I looked in article 250 and 550 and did not see the exception. Can someone tell me where its located? Thanks