As far as i know, and providing you are talking about 3 phase, you need 5 wires. That is, earth, neutral, and the 3 phases. Some machinery does not require the neutral wire, but i believe the Tesla does. SPECIFICALLY talking ONLY about the mobile connector supplied with the car, at MAXIMUM efficiency it can only charge to 50km per hour, so a single onboard charger is sufficient. I have not seen the spec for the new WALL connector which is 3phase, but i assume it will allow 32 amps per phase. That being the case, if you want to take full advantage of THAT connector, then you need 2 onboard chargers with should give about 100 to 110 km per hour. ECIT, the car works out at about 200wh per km. Amps x volts equal watts. Therefore 1 kw gives approx 5km. If you are drawing 32 amps on the single phase wall connector, 32x240 = 7.68 kw. 7.68 X by 5=38.5 km more or less per hour. Bear in mind losses occur. This is ONLY for single phase. The calculations are a bit different with 3 phase and not quite as straight forward.