Abstract: The invention relates to an insulator for an electrical conductor provided with an outer shield, especially a so-called coaxial cable or shielded twin cable, in order to achieve an insulation at the shield that insulates against DC and low frequency AC signals transforming through the conductor and that includes a first and a second element (3,4) formed from electrically conducting material that by means of a dielectric (5) are electrically insulated and delineated from one another. and that are intended to be connected between an interruption at the shield or between the shield and an external earth connection.