Terminal casing comprising at least one upper cover and one lower cover in which there is made a housing that can be closed by means of a removable hatch having a curvilinear profile, characterized in that: - the hatch, or the lower cover, comprises a plurality of grooves (55 1 -55 8) distributed longitudinally on at least two parallel faces in following said curvilinear profile, - the lower cover, or the hatch respectively, comprises a plurality of tabs (25 1 -25 8) distributed longitudinally on at least two parallel faces in following said curvilinear profile, each tab being designed to cooperate with an associated groove, in that the tabs and the grooves are shaped so as to enable: - through a first combination of motions comprising a translational motion followed by a rotational motion of the hatch, an insertion and a guidance respectively of the tabs in the grooves, when the hatch is inserted into the lower cover according to a direction of insertion of the hatch, - through a second combination of motions comprising a rotational motion followed by a translational motion of the hatch, a guidance of the tabs in the grooves and a withdrawal of the tabs from the grooves respectively, when the hatch is withdrawn from the cover according to a direction of withdrawal of the hatch opposite to the direction of insertion; and in that: - the grooves of each face are each tilted relative to the curvilinear profile by an angle of tilt that increases in the direction of withdrawal of the hatch and decreases in the direction of insertion of the hatch, - the tabs of each face are each tilted relative to the curvilinear profile by an angle of tilt that increases in the direction of withdrawal of the hatch and decreases in the direction of insertion of the hatch. - the hatch, or the lower cover, comprises a plurality of grooves (55 1 -55 8) distributed longitudinally on at least two parallel faces in following said curvilinear profile, - the lower cover, or the hatch respectively, comprises a plurality of tabs (25 1 -25 8) distributed longitudinally on at least two parallel faces in following said curvilinear profile, each tab being designed to cooperate with an associated groove, - through a first combination of motions comprising a translational motion followed by a rotational motion of the hatch, an insertion and a guidance respectively of the tabs in the grooves, when the hatch is inserted into the lower cover according to a direction of insertion of the hatch, - through a second combination of motions comprising a rotational motion followed by a translational motion of the hatch, a guidance of the tabs in the grooves and a withdrawal of the tabs from the grooves respectively, when the hatch is withdrawn from the cover according to a direction of withdrawal of the hatch opposite to the direction of insertion; - the grooves of each face are each tilted relative to the curvilinear profile by an angle of tilt that increases in the direction of withdrawal of the hatch and decreases in the direction of insertion of the hatch, - the tabs of each face are each tilted relative to the curvilinear profile by an angle of tilt that increases in the direction of withdrawal of the hatch and decreases in the direction of insertion of the hatch.