I've searched forum but haven't found answer I'm looking for. I have a 480/277 panel 3P 4W and a contractor wants to run a straight 480 3P 3W sub panel off it. What are the requirements per the NEC. I believe not running a neutral is ok, but what rating does the sub panel and breakers have to have? Should everything be 480 rated or is 480/277 ok for panel and breakers? Obviously no 277 circuits will be run from sub but I think a 120/208 x-former and 480 single and three phase equipment. I've looked at 240.85, but I dont think that pertains to this. Thanks