Abstract: A cable failure device for a mobilizing a garage door in the event of a failure of one of the cables or one of the elements holding the cables is described. The cable failure device of the invention includes a support structure mounted on the cable operated door and includes a connection point onto which a tensioned cable is connected. A braking assembly is mounted onto the support structure and includes a casing mounted onto the support structure and a brake operable between a rest position and an operable position. The brake is movably mounted to the support structure and is located adjacent the outside of a fixed frame such as guide rails and is adapted to co-operate with a roller on the garage door so that a portion of the guide rail lies between the roller and the brake. A tension detector co-operating with the tension cable is provided for detecting a tension in the tension cable and an actuator is operatively connected to the tension detector and to the brake.