A method for sectioning a medium-voltage distribution electric line evidencing a disturbance using a section switch. The steps are: (a) detecting a current having an amplitude and a wave form profile in the medium-voltage line; (b) analyzing the wave form profile to determine whether the fault is transient, permanent, a transformer input current or transformer in-rush current; (c) and determining the behavior of the section switch from the result of the wave form profile analysis. The section switch is installed on auxiliary branches of a distribution network having a main line that is protected by an automatic reset circuit breaker. The section switch has an opening mechanism having a coil and an electronic circuit. The electronic circuit has a power source for the coil and electronic circuit, a detector to detect current and an analyzer to determine whether the detected current is a transient or a permanent fault.