The invention relates to an electrical cable (200) intended to be used in a harness (1) to supply power to pieces of electrical equipment, comprising at least: a conductive core (210) comprising at least one conductive strand (211), and an insulating jacket (220) placed around the conductive core. The insulating jacket of the cable has a relative dielectric permittivity lower than or equal to 2 and comprises: a first layer (221) comprising a polymer aerogel, and a second layer (222), covering the first layer, comprising a fluoropolymer. The invention also relates to a harness comprising such an electrical cable.