Cabling system for connecting, to a plurality of electronic printed circuit boards, a common electrical cable, for example a grounding cable, and respective electrical board cables, for example power supply cables for independently powering at least some of said electronic boards, comprising: - a bundle of electrical cables comprising the common electrical cable and the plurality of board cables, at least some of said board cables being intended to be connected independently to the respective electronic boards; - a plurality of multipolar, insulation-piercing connectors placed in succession along said bundle of cables, each of said connectors being suitable to be connected to a respective electronic board for electrically connecting, to said electronic board, the common cable and at least one board cable, each insulation-piercing connector, with the exception of a terminal connector that terminates the bundle of cables, being suitable to receive the common electrical cable, the board cable to be connected to the respective electronic board, and the board cables that must be connected to the successive connectors, and being suitable to transmit to a successive insulation-piercing connector, or the terminal connector, the common electrical cable and the board cables that must be connected to the successive connectors, wherein each insulation-piercing connector is provided with cable seats electrically insulated from each other and suitable to receive respective cables in input to the connector, wherein the cable seats for the cables that exit from the connector are pass-through seats, and wherein the cable seats for the cables that must be electrically connected to the electronic board to which the connector is fixed, are engageable by respective insulation-piercing electrical contacts suitable to cut or pierce the respective electrical cable, wherein each pass-through cable seat is not provided with an insulation-piercing electrical contact or all the cable seats have insulation-piercing electrical contacts but not all the electrical contacts are electrically connected to the respective electronic board. - a bundle of electrical cables comprising the common electrical cable and the plurality of board cables, at least some of said board cables being intended to be connected independently to the respective electronic boards; - a plurality of multipolar, insulation-piercing connectors placed in succession along said bundle of cables, each of said connectors being suitable to be connected to a respective electronic board for electrically connecting, to said electronic board, the common cable and at least one board cable, each insulation-piercing connector, with the exception of a terminal connector that terminates the bundle of cables, being suitable to receive the common electrical cable, the board cable to be connected to the respective electronic board, and the board cables that must be connected to the successive connectors, and being suitable to transmit to a successive insulation-piercing connector, or the terminal connector, the common electrical cable and the board cables that must be connected to the successive connectors, wherein each insulation-piercing connector is provided with cable seats electrically insulated from each other and suitable to receive respective cables in input to the connector, wherein the cable seats for the cables that exit from the connector are pass-through seats, and wherein the cable seats for the cables that must be electrically connected to the electronic board to which the connector is fixed, are engageable by respective insulation-piercing electrical contacts suitable to cut or pierce the respective electrical cable,