A blood pump system for left ventricle assist has an implantable pump unit having a multiphase stator having a plurality of windings connected between respective junctions for forming first, second, and third phases. An external control unit comprises an H-bridge inverter having first, second, and third phase legs. A percutaneous cable is provided having first, second, and third parallel pairs of redundant conductors. Each conductor pair is connected between a respective phase leg and a respective junction. The conductors are arranged concentrically around a cable core so that individual conductors of each pair are separated by at least one conductor of a different conductor pair.