jar546
CBO
OK so this one is the most complicated of them all. Impedance is a major factor and there is more than one way to do this. This calculator is base on those that already know the available fault current at the secondary taps of the POCO or owned transformer. For us in Florida, FPL provides that unless we have a pad mounted transformer with a readable dataplate. Then we can figure that ourselves. This one errs on the side of caution and reads a little high for safety sake.