Our 17 Rex takes 4.5 hours to charge on a dedicated 240V circuit(which was wired with really thick gauge cable and paired with a 50 Amp breaker) here in the US. The voltage on it fluctuates between 225 and 255V. Our i3 maxes out around 31 Amps due to its internal charging limit set by BMW. The math on our charging scenario with our Juicebox Pro 40 works out to about 33.4 kWh of energy pushed into the car including charging losses over those 4.5 hrs of time. Not all 220-240V outlets are created equal and the BMW salesman may have been a bit optimistic. Most existing dryer outlets in garages in the US max out at 30 Amps and are on a 30 Amp breaker, but can only safely provide about 24-26. I wouldn't push them higher for such prolonged periods of time so the charging equipment used should be limited below the max that the i3 can pull (32 Amps) else there's risk involved with wiring and breakers on existing circuits. I suppose there could be significant variance in wiring depending on country, local electric codes n such.
Current daily driver: 2017 BMW i3 Rex
Past car history: Nearly a dozen 85-89 Toyota MR2s including 88 Supercharged, 96 Lexus SC300, 05 Tacoma 4x4 manual, 11 Golf TDI, 01 Honda Insight manual