A try to make it short: The Roadster can charge up to 70A from a single phase. But we have three phases in Europe/Switzerland and you should not use more than 16A per single phase (3,6kVA - Werksvorschriften). So charging higher than 16A (32A, 40A, 63A, 70A) from a single phase is against those specifications. Plus charging at high power needs thicker cables (just look how thick the 70A HPC cable is). If you charge from all three phases together at the same time you can charge at higher rates than the 16A - for example say 50A or more. Example: Charging single phase from a CEE16 (blue, single phase) socket -> 3'680 W (16A*240V) Charging three phase from CEE16 (red, three phase) socket -> 11'000 W (that's almost 48A if we would use single phase) So we have almost 3 times more power when using all three phases - without upgrading the cables!