My trusted electrician just left. We have a 400 amp service with two 200amp boxes in the house with breaker protection on each of them. He is going to add another 400amp service and run it about 125 feet underground around the house and then back into the garage. I'm pretty sure he said he'd use 6 gauge wire for this run. Please correct me if I misunderstood. This would be run to another 200amp panel in the garage for the NEMA 14-50 and the HPWC with 50amp and 100amp circuit protection. He said that the transformer is 50Kva (does that sound right?) and is more than enough. BUT the wires from the transformer are ALREADY not enough for the house. As an example he said that the wire he was going to run underground around to the garage will carry more than the wires from the transformer right now. He said the minimum he would accept from the PoCo from the transformer for the new setup would be 750 MCM. Not sure MCM is correct but the 750 is definitely the number he said. He is aware that within two years we will most likely have a ModelX in the same garage charging at the same time as the MS. Opinions? Advice? Comments? Flasher? Knox? All you smart people please let me know what you think.