A method of improving immunity of a three-phase electric cable to external magnetic fields, said three-phase electric cable comprising a respective current conductor for each electrical phase thereof, the method comprising: splitting each of the respective current conductors of the three-phase electric cable into two ( n =2) electrically insulated sub-conductors for forming a three-phase cable arrangement having the improved immunity to the external magnetic fields; determining a cross-sectional area for each one of said two electrically insulated sub-conductors to provide a desirable maximal electrical current density of said respective current conductor; arranging the electrically insulated sub-conductors in said cable arrangement in an intervening fashion such that each electrically insulated sub-conductor is placed adjacent and alongside at least one neighboring electrically insulated sub-conductor associated with a different electrical phase of said three-phase electric cable; and for each of said respective current conductors, electrically connecting in parallel the two electrically insulated sub-conductors associated with said respective current conductor, characterized in that the determining of cross-sectional area for each one of said electrically insulated sub-conductors is such that for each respective current conductor a sum of the cross-sectional areas determined for the two electrically insulated sub-conductors associated with said respective current conductor is smaller than a cross-sectional area of said respective current conductor for said maximal electrical current density, and an attenuation factor of said three-phase electric cable arrangement to external magnetic fields is about 5.5, 10.7, 21.1, 31.5, 52.4, 73.2, and 104.6, for an external magnetic field source at a distance of about 0.1, 0.2, 0.4, 0.6, 1.0, 1.4, and 2.0 meters, respectively, from said three-phase cable arrangement. splitting each of the respective current conductors of the three-phase electric cable into two ( n =2) electrically insulated sub-conductors for forming a three-phase cable arrangement having the improved immunity to the external magnetic fields; determining a cross-sectional area for each one of said two electrically insulated sub-conductors to provide a desirable maximal electrical current density of said respective current conductor; arranging the electrically insulated sub-conductors in said cable arrangement in an intervening fashion such that each electrically insulated sub-conductor is placed adjacent and alongside at least one neighboring electrically insulated sub-conductor associated with a different electrical phase of said three-phase electric cable; and for each of said respective current conductors, electrically connecting in parallel the two electrically insulated sub-conductors associated with said respective current conductor, characterized in that the determining of cross-sectional area for each one of said electrically insulated sub-conductors is such that for each respective current conductor a sum of the cross-sectional areas determined for the two electrically insulated sub-conductors associated with said respective current conductor is smaller than a cross-sectional area of said respective current conductor for said maximal electrical current density, and an attenuation factor of said three-phase electric cable arrangement to external magnetic fields is about 5.5, 10.7, 21.1, 31.5, 52.4, 73.2, and 104.6, for an external magnetic field source at a distance of about 0.1, 0.2, 0.4, 0.6, 1.0, 1.4, and 2.0 meters, respectively, from said three-phase cable arrangement.