A conductor for electric lines includes a load-bearing core on which conductors for electric energy transportation are arranged. The load-bearing core includes a plurality of aligned aramidic fibres defining one or more ropes wrapped in one or more sheaths.

Systems, methods and tools for the interrogation of fiber-reinforced composite strength members to assess the structural integrity of the strength members. The systems and methods utilize the transmission of light through optical fibers that are embedded along the length of the strength members. The inability to detect light through one or more of the optical fibers may be an indication that the structural integrity of the strength member is compromised. The systems and methods may be implemented without great difficulty and may be implemented at any time in the life cycle of the strength member, from production through installation. The systems and methods have particular applicability to bare overhead electrical cables that include a fiber-reinforced strength member.

The invention concerns an electric power transmission cable, particularly for an overhead power line, comprising at least one central composite ring (1) formed of fibers impregnated by a matrix, of which the specific breaking strength is greater than 0.4 MPa.Math.m.sup.3/kg and at least one layer of conductive wires (3) nested within one another, made of aluminum or an aluminum alloy and windings around said ring (1), said cable having an outer diameter at ambient temperature called the initial diameter (D.sub.i) and the ratio between the thermal expansion coefficient of the conductive wires (3) and that of the central ring (1) is greater than three. According to the invention, said conductive wires (3) nested within one another are of a geometry such that the increase in the outer diameter of one length of said cable shorter than 45 m, during an increase of temperature lasting two to four minutes, from ambient temperature to a temperature between 150 and 240 C., is less than or equal to 10% of the initial diameter (Di), said cable being subject to a mechanical tension between 10% and 30% of the nominal breaking strength of the cable. The invention also concerns a conductive wire geometry enabling such a level of expansion of the diameter.