The construction (M10) has an outer casing, and an attachment ring (20), which has an inner circumferential surface corresponding to an inclination of an outer circumferential surface (14) of a water containment part. The ring slides towards an axis of a shielded cable so as to exert pressure at an end section of the cable to reduce a diameter of the part, in a condition, with which an inner circumferential surface (24) of the ring is arranged on the outer circumferential surface.