Without documentation indicating that the equipment presents a balanced load, it should not be assumed that it will. If the equipment power lead has a neutral then it is probably not a completely balanced load and the neutral will probably need to be connected. The consequences of not connecting the neutral could be excessive voltages getting applied to some parts and reduced voltages getting applied to other parts of the equipment. This is not good. If the equipment does always present a balanced load, it may allow the option of connecting it in wye (star) or delta format and the supply voltage required would be different in each case. To clarify the voltage specification, there are two different ways of specifying the voltage in a three phase system. The "phase voltage" is the voltage between any one of the three live conductors and the neutral conductor. The "line voltage" is the voltage between any two of the three live conductors. The line voltage is sqrt(3) times higher than the phase voltage. The line voltage provided by the supply should match the line voltage required by the equipment. The same applies to the phase voltage, although if one matches, the other will also. Phase voltage doesn't really have a lot of meaning for a system without a neutral and such a system should be specified by line voltage only. Regards, Peter Coghlan.