I have a machine which is wired as 3 phase neutral and earth and is 15.1KW, there are no 415v components and all components are 230v, so effectively it is using 3 single phase circuits, however I have always carried out the circuit breaker calculation based on the 415V potential, I.E> 15120W divided by 415V =36.43 therefore I would fit a 40Amp 3 phase breaker, I have been told by the manufacturer that I have incorrectly calculated this and should divide this calculation by 3 to calculate the correct 3 phase breaker and i should fit a 12A 3 phase breaker, I am not convinced that this is correct but am now second guessing myself, can any one assist.