Abstract: A rigid electrical insulator of the type having a base or a pin at its bottom and having at least one groove (18 or 19) for receiving an electrical cable at its top, the insulator being characterized by the fact that it includes at least one central rod (1) fixed at its bottom end to the base (5) or to the pin and at its top end to a rigid head (7) provided with at least one channel (8 or 9), the outside faces of the rod and of the rigid head (7) being covered in waterproof manner by a covering (10), with the head covering being of a flexible elastomer and the rod covering being selected from elastomers, resins, and varnishes, the groove (18 or 19) being defined by the channel (8 or 9) covered by its covering.