Tesla is building a 200 bay Bucces sized Supercharger they don’t have a habit of failure their engineers are world class. They will string in 66.4 kilovolt distribution from the closest substation and use on-site 66kv to 480/3phase in banks of 50 chargers that’s a 12,500Kva transformer a common size in medium voltage power engineering. They would need four of them on-site. The site they chose is near a nuclear plant you can bank pun intended they will hardwire to the substation driven by that plant.
It’ll be a lot more interesting to see those sort of charging facilities spring up off of rural interstate off-ramps, very far from the nearest nuke power plant. That’s the real test - putting them where they’ll be needed, not cherry-picked locations that are ideal as proof-of-concept. Musk may be smart and ambitious, but large scale EV adoption is realistically a fifty-year project - IF we can afford it.