Abstract: Electrical cable, in particular for medium- or high-voltage power transmission or distribution, having a metal shield and a semiconductive water-blocking expanded layer. This layer exerts three main functions, the first one is to elastically and uniformly absorb radial forces of expansion and contraction of the cable coating layers due to thermal cycles of the cable during use, thus preventing deformations or breakages in the metal shield, the second one is to ensure electrical continuity between the cable core and the metal shield, the third one is to effectively avoid penetration and propagation of moisture and/or water along the cable core due, e.g., to possible ruptures in the metal shield. The third function is obtained by including in the expanded layer a water-swellable material.

Abstract: A cable, in particular a cable for electric power transmission or distribution, having an inner layer comprising a self-repairing material with a predetermined cohesiveness and a controlled flowability, so as to re-establish, upon creation of a discontinuity in at least one of the cable coating layers, the continuity in the coating. The discontinuity in the coating can be caused by mechanical abuses of various types, for example accidental impact with cutting tools. Infiltration of moisture and generation of leakage currents, leading to a rapid corrosion of the conductor, are in this way avoided.

Abstract: A cable, in particular a cable for electric power transmission or distribution, having an inner layer comprising a self-repairing material with a predetermined cohesiveness and a controlled flowability, so as to re-establish, upon creation of a discontinuity in at least one of the cable coating layers, the continuity in the coating. The discontinuity in the coating can be caused by mechanical abuses of various types, for example accidental impact with cutting tools. Infiltration of moisture and generation of leakage currents, leading to a rapid corrosion of the conductor, are in this way avoided.

Abstract: The disclsoure describes an electric conductor having a coating layer with the property of strippability so that it can be stripped from the electric conductor, and a method for controlling the strippability of the coating layer from the electric conductor, with the electrical insulation properties of the cable coating being kept constant after exposure to moisture. The method involves adding to a polymeric composition forming the coating layer a predetermined amount of a polyolefinic compound, which contains at least one unsaturation and at least one carboxyl group in the polymer chain.

Abstract: The disclosure sets out a fire-retardant electrical cable including a metal conductor and at least a double layer polymer coating disposed to surround the metal conductor. The double layer coating defines an inner and an outer layer wherein the inner layer includes a polymer matrix, a predetermined first amount of a flame retardant inorganic filler and a predetermined amount of a coupling agent. The outer layer includes a polymer matrix and a predetermined second amount of a flame retardant inorganic filler. The inner layer employs the predetermined first amount of inorganic filler in an amount lower than the predetermined second amount of inorganic filler in the outer layer. The inner layer includes the predetermined amount of coupling agent in an amount such that upon placing the cable in water, it keeps the long term insulation resistance of the cable substantially constant.

Abstract: A cable, in particular a cable for electric power transmission or distribution, having an inner layer comprising a self-repairing material with a predetermined cohesiveness and a controlled flowability, so as to re-establish, upon creation of a discontinuity in at least one of the cable coating layers, the continuity in the coating. The discontinuity in the coating can be caused by mechanical abuses of various types, for example accidental impact with cutting tools. Infiltration of moisture and generation of leakage currents, leading to a rapid corrosion of the conductor, are in this way avoided.