Single phase power System transient short circuit phenomenon. The short circuit current is conpound by a steady state sinusoidal component and an initual unidirectional exponential term decreasing as time goes by. The first current peak, in this case may reach 3 kA (almost 1,5 times the steady state peak current). This first peak depends in the instant when The breaker is closed or, more in general, the time when the short circuit fault occurs. Current overpeak in inductive circuit always occurs, but it is really important to account in case of short circuit and faults in Order to guarrantee that breakers Will be able to interrupt such a current peak without being damaged.