Patent ID: 7166936

Claim:
A method for controlling an electric switching device for alternating current arranged in a current path for opening this device for breaking the current in the current path after occurrence of a fault current in the current path, wherein the current in the current path is detected and the electric switching device is controlled to break the current in the current path directly after a half wave of the alternating current having a peak current below a predetermined current limit value, so that the breaking is completed at a zero-crossing of the alternating current terminating a said half wave; and wherein a peak current value is determined through said current detection of two consecutive half waves of the alternating current after occurrence of the fault current and these peak current values are compared with each other, and that the switching device is controlled to break the current in the current path after a half wave of the alternating current corresponding to said half wave with the same sign as the half wave for the lowest of the peak current values and complete the breaking at a zero crossing of the alternating current after a said half wave.