Usually you can use a standard RCA cable (with or without ground wire) and connect the separate grounding wire using any simple cable. As the old Oracle's used an acrylic arm mount, we had to have separate grounding points and ground cables for chassis and tonearm, eventually with a third wire going to the motor. All of them connected to the the ground lug on the phono amplifier. If by any reason the motor case was connected to ground of the mains for safety reasons (not usual, but some after-market power supplies had this characteristic ), you should not connect the motor ground wire to the phono it, as it would create a ground loop injecting noise in the phono ground.
