Cord for high thermal limit, with low mass and high current capacity, low corona effect and low deformation at high loads, suitable for installation on high voltage overhead lines under extreme climatic conditions (wind and ice) by virtue of its very high ultimate tensile strength. The cord is composed of a core about which at least one ring of quoins of electrically conductive material is wrapped. The core consists of at least three mutually resting twisted-together load-bearing cables, each formed from a plurality of twisted-together wires formed of composite hybrid carbon/glass fibre material and protected by an aluminium sheath (6). At least three aluminium filler elements are provided, twisted together with said load-bearing cables. The load-bearing cables and the filler elements are surrounded by a longitudinally welded second aluminium, or bound with a tape of conductive material.