A disconnector and related surge arrester include first and second connection terminals connecting to active electrical leads, between which a protection element is inserted, having electrodes electrically connected to the connection terminals, a disconnector between the first terminal and an electrode of the protection element including a metal plate having a base end electrically connected to the first terminal and a distal end maintained electrically connected to the electrode, the plate being able to sublimate in the presence of short-circuit currents above a preset threshold, an intercepting slider, mounted longitudinally slidable along a longitudinal direction which lies between the base end of the lamina and the electrode of the protection element to intersect development of an electric arc, a sliding guide for the intercepting slider, the slider being biased in the longitudinal direction, through a preloaded elastic unit, towards an intercepting position abutting a portion of the plate.