My background is mechanical engineering so not great with the electrical side. I plan on buying a air-preheater (resistive wire heated) which has a power rating of 30kW, supplied by 3-phase. I need to determine whether my 3-phase supply (415V 32A) has a max current that can cope with this. My calculation is as follows: since purely resistive, power factor =1 hence, kW=kVA=30kW line to neutral voltage=line to line voltage/3^1/2=230V 3-phase power is 30kW, therefore single phase power = 10kW Current=VA/line to neutral voltage=10000/230=43.478 amps As far as I am aware this is the current rating from my supply i would need to achieve 30kW from 400V. Do my calculations appear correct? If so I will need to find a power supply rated above this current.