I have noted in the training videos that in a three phase system configuration, the negative out of the 3 phase MUST be connected (/or in this case the 9 units).
May the negatives from Quattros be interconected between units but be isolated from the negative loads (or NEG from generator if the case), or they MUST be connected to NEG from the load all the time?.
I normally install a 4x100Amp breaker and neg is disconected from load on each 3 phase line, and maybe I am doing this wronly.
Regards.