I have crossed paths with a 3 phase 45KVA 480VAC Isolation XMFR on rubber wheels. I'm not sure what to make of this install and use of a transformer. I'm concerned about the electrical shock potential. I might guess its not unlike a welder, another transformer on wheels. I've looked over Articles 450 and 250 and believe this install can be on wheels but may require a grounding rod to be driven. There are no specific details for a portable transformer. Any thoughts would be helpful.