UL 635 covers insulating bushings and accessories for insulating bushings used for the following purposes in electrical equipment: a)Insulating bushings used for the protection of cables, flexible cords, and insulated wires, where routed through internal or external walls of electrical equipment; b) Insulating bushings used to provide strain-relief for flexible cord and single conductor insulated wiring and to protect such cords or wiring; and c) Accessories to insulating bushings used to supplement the characteristics of the bushing.