Five 30A x 208/240V drops terminating with Nema L6-30r receptacles. Get Some PDUs to plug into those. Save
the last 10A of headroom for some huge ass fans. You'll need them.
You don't get 208V with a normal residential service. 208V is one leg of a 3-phase service .. usually data-center grade.
What you get with a residential service is 250V split phase. That should be good enough for mining, but the data-center PDUs are not rated for it.
https://bitcointalk.org/index.php?topic=521520.msg8182756#msg8182756Have fun!