I have been informed that we can no longer terminate two or more branches of a radial circuit into the DB/CU. Because of increased fault currents potentially exceeding the breaking capacity of the protective device, if there were two simultaneous faults on the two branches. But it is still acceptable to split the radial into branches when it leaves the DB/CU after the first point of utilisation(which could be very close to the origin of the circuit). I am struggling to understand the significant difference in fault currents between these two scenarios. I was directed to Fig15B in the big book, where it no longer depicts a radial circuit's two branches connected to the DB/CU. Does that potentially small length of the radial circuit's conductors at the beginning of the circuit, before it branches, add enough extra impedance to make a difference?
