Protection device for an electrical control system operable by a control member and positioned in a control panel, comprising: - a body having a longitudinal axis designed to extend perpendicularly to a wall of said control panel, - a rotary hood, movable around an axis of rotation (X2-X'2) coaxial with the longitudinal axis of said body, between a rest position wherein it prevents access to said control member so as to prevent operation of the electrical control system, and an access position wherein it allow access to the control member for the purpose of manual operation by a user, characterized by - a first cam and a second cam accommodated in said body, - the first cam being integral in rotation with said hood, and the second cam being movable only in translation with respect to the body in an axial direction parallel to the axis of rotation of the hood and driven toward the first cam by an elastic member, - the first and the second cam having cam profiles (P1, P2) adapted to one another for obtaining successively, from the rest position toward the access position: (i) a first stable interlocking in said axial direction of the first and the second cam in the rest position, (ii) a translation of the second cam in said axial direction counter to the pressure of the elastic member under the influence of the rotation of the first cam to a position of unstable equilibrium beyond which the elastic member drives the second cam in translation approaching the first cam, (iii) a second stable interlocking in said axial direction of the first and the second cam in the access position. - a body having a longitudinal axis designed to extend perpendicularly to a wall of said control panel, - a rotary hood, movable around an axis of rotation (X2-X'2) coaxial with the longitudinal axis of said body, between a rest position wherein it prevents access to said control member so as to prevent operation of the electrical control system, and an access position wherein it allow access to the control member for the purpose of manual operation by a user, - a first cam and a second cam accommodated in said body, - the first cam being integral in rotation with said hood, and the second cam being movable only in translation with respect to the body in an axial direction parallel to the axis of rotation of the hood and driven toward the first cam by an elastic member, - the first and the second cam having cam profiles (P1, P2) adapted to one another for obtaining successively, from the rest position toward the access position: (i) a first stable interlocking in said axial direction of the first and the second cam in the rest position, (ii) a translation of the second cam in said axial direction counter to the pressure of the elastic member under the influence of the rotation of the first cam to a position of unstable equilibrium beyond which the elastic member drives the second cam in translation approaching the first cam, (iii) a second stable interlocking in said axial direction of the first and the second cam in the access position. (i) a first stable interlocking in said axial direction of the first and the second cam in the rest position, (ii) a translation of the second cam in said axial direction counter to the pressure of the elastic member under the influence of the rotation of the first cam to a position of unstable equilibrium beyond which the elastic member drives the second cam in translation approaching the first cam, (iii) a second stable interlocking in said axial direction of the first and the second cam in the access position.