400V refers to European 3-phase 230V. You will not be able to charge any faster in Europe than in the USA, the maximum charge rate for this car is determined by the OBC (On Board Charger) which is 9.6 kW (9600 watts) at 240 volts which is 40 Amps.
There is no DCFC (DC Fast Charge) option for the B-Class, and I would not consider it ever being possible unless Tony Williams of www.quickchargepower.com sees a market for his JDeMo add -on. He currently installs these add-ons for owners of the Toyota RAV4 EV which is also a Tesla battery and motor.
Mercedes says they are making an all-new B250e in a couple of years with their own battery, their own motor, and their own charging system -- definitely with DCFC. Research Mercedes ELC.
Many answers found here:
https://answers.yahoo.com/question/index?qid=20100221075203AANuZ1O
The 400 volt number comes from √3 times 230. It is the phase to phase voltage corresponding to 230 volts phase to ground.
It is a 3 phase circuit. If the line to neutral voltage is 230, the line to line voltage is sqrt(3)*230=about 400 volts. A circuit always need two wires. If you use a line and neutral you get 230; if you use 2 lines, you get 400.
On 1st Jan 1995 government agreed that the electricity supplies are to be harmonized with the rest of Europe, from 415 V and 240 V to 400 V and 230 V.
