Maximum Phase Fault Current Calculation
Maximum Phase Fault Current Calculation The total impedance is the sum of the impedances of the conductors from the origin of the installation to the circuit under consideration. For single phase circuits, the maximum fault current is between the phase and the neutral and in three phase circuits it is when all phases are shorted (symmetrical current). The total impedance is that with operating temperature 20οC (lower temperature means lower resistance). In particular: For single phase circuits: For three phase circuits: With:

Protective Device Breaking Capacity Check
