A follower cap drive system for a fast grounding device, said system comprising: • a guide casing that is stationary; • a grounding rod mounted to slide longitudinally relative to the guide casing in order to be put in contact with a stationary contact of the grounding device; • a follower cap placed on the same axis as the grounding rod, positioned around the axis and designed to follow said grounding rod over a determined fraction of its stroke; and • a slide on which the grounding rod is fastened, driven by a drive rod and sliding longitudinally relative to the guide casing; the system being characterized in that it comprises: • a trigger pivotally mounted about a trigger pin that extends perpendicularly on the grounding rod, the trigger itself comprising: * a first end referred to as an abutment end; and * a second end referred to as a blocking end offset angularly relative to the abutment first end by about 90°; • a stationary abutment of the guide casing placed on the path of the abutment end of the trigger in order to cause the trigger to pivot in a determined first direction when the follower cap is required to stop during closing of the grounding device and thus release the follower cap; and • a movable abutment secured to the follower cap and placed on the path of the abutment end of the trigger, being placed relative to the abutment end of the trigger on its side remote from the stationary abutment in order to cause the trigger to pivot in a second direction opposite to the first direction, during opening of the grounding device and to drive the follower cap together with the grounding rod. • a guide casing that is stationary; • a grounding rod mounted to slide longitudinally relative to the guide casing in order to be put in contact with a stationary contact of the grounding device; • a follower cap placed on the same axis as the grounding rod, positioned around the axis and designed to follow said grounding rod over a determined fraction of its stroke; and • a slide on which the grounding rod is fastened, driven by a drive rod and sliding longitudinally relative to the guide casing; • a trigger pivotally mounted about a trigger pin that extends perpendicularly on the grounding rod, the trigger itself comprising: * a first end referred to as an abutment end; and * a second end referred to as a blocking end offset angularly relative to the abutment first end by about 90°; * a first end referred to as an abutment end; and * a second end referred to as a blocking end offset angularly relative to the abutment first end by about 90°; • a stationary abutment of the guide casing placed on the path of the abutment end of the trigger in order to cause the trigger to pivot in a determined first direction when the follower cap is required to stop during closing of the grounding device and thus release the follower cap; and • a movable abutment secured to the follower cap and placed on the path of the abutment end of the trigger, being placed relative to the abutment end of the trigger on its side remote from the stationary abutment in order to cause the trigger to pivot in a second direction opposite to the first direction, during opening of the grounding device and to drive the follower cap together with the grounding rod.