A mechanical assembly for a wire-fuse circuit-breaker, the assembly being adapted to be removably and pivotally mounted between two parts of a support of the circuit-breaker, the assembly including: · a fuseholder tube adapted to accommodate a fuse wire and having an upper end that includes a dome adapted to close the tube, to enable the insertion of one end of the fuse wire, and to hold it in place and having a lower end that is open to allow gases produced by breaking the fuse wire to exhaust, the fuseholder tube being adapted to be mounted to pivot between an open position in which it is in contact only with the lower part of the support and a closed position in which it is also in contact with and abutted against the upper part of the support, characterized in that it comprises: · a fuse-breaker including: · a trunnion on which the fuseholder tube is pivotally mounted, including pins adapted to be removably mounted on the lower part of the support to enable pivoting of the mechanical assembly relative thereto, and means for fixing the other end of the fuse wire; · a drive lever mounted to pivot on the trunnion and adapted to be actuated by an operator; · a breaking lever mounted to pivot relative to the trunnion and adapted to be actuated by the drive lever and to stretch the fuse wire mechanically to break it; · in which assembly the direction of pivoting of the drive lever on the trunnion is the opposite of the direction of pivoting of the fuseholder tube and the mounting of the levers and the fuseholder tube on the trunnion leaves sufficiently clear the area in the vicinity of the open lower end of the tube regardless of the position of the levers and the tube in order to allow gases produced by breaking the fuse wire to exhaust without disturbing the flow thereof. · a fuseholder tube adapted to accommodate a fuse wire and having an upper end that includes a dome adapted to close the tube, to enable the insertion of one end of the fuse wire, and to hold it in place and having a lower end that is open to allow gases produced by breaking the fuse wire to exhaust, the fuseholder tube being adapted to be mounted to pivot between an open position in which it is in contact only with the lower part of the support and a closed position in which it is also in contact with and abutted against the upper part of the support, characterized in that it comprises: · a fuse-breaker including: · a trunnion on which the fuseholder tube is pivotally mounted, including pins adapted to be removably mounted on the lower part of the support to enable pivoting of the mechanical assembly relative thereto, and means for fixing the other end of the fuse wire; · a drive lever mounted to pivot on the trunnion and adapted to be actuated by an operator; · a breaking lever mounted to pivot relative to the trunnion and adapted to be actuated by the drive lever and to stretch the fuse wire mechanically to break it; · in which assembly the direction of pivoting of the drive lever on the trunnion is the opposite of the direction of pivoting of the fuseholder tube and the mounting of the levers and the fuseholder tube on the trunnion leaves sufficiently clear the area in the vicinity of the open lower end of the tube regardless of the position of the levers and the tube in order to allow gases produced by breaking the fuse wire to exhaust without disturbing the flow thereof. · a fuse-breaker including: · a trunnion on which the fuseholder tube is pivotally mounted, including pins adapted to be removably mounted on the lower part of the support to enable pivoting of the mechanical assembly relative thereto, and means for fixing the other end of the fuse wire; · a drive lever mounted to pivot on the trunnion and adapted to be actuated by an operator; · a breaking lever mounted to pivot relative to the trunnion and adapted to be actuated by the drive lever and to stretch the fuse wire mechanically to break it; · a trunnion on which the fuseholder tube is pivotally mounted, including pins adapted to be removably mounted on the lower part of the support to enable pivoting of the mechanical assembly relative thereto, and means for fixing the other end of the fuse wire; · a drive lever mounted to pivot on the trunnion and adapted to be actuated by an operator; · a breaking lever mounted to pivot relative to the trunnion and adapted to be actuated by the drive lever and to stretch the fuse wire mechanically to break it; · in which assembly the direction of pivoting of the drive lever on the trunnion is the opposite of the direction of pivoting of the fuseholder tube and the mounting of the levers and the fuseholder tube on the trunnion leaves sufficiently clear the area in the vicinity of the open lower end of the tube regardless of the position of the levers and the tube in order to allow gases produced by breaking the fuse wire to exhaust without disturbing the flow thereof.