Actuation systems and lithographic apparatus which address the issue of uncontrolled return of common mode currents are provided. In an embodiment such systems aim to prevent the occurrence of corona and discharge between high voltage electric cables in low pressure environments. An exemplary actuation system includes comprises an actuator module, a power source and power transmission cables. The actuator module includes an electrical motor and a first plurality of shielded cables configured to connect to the electrical motor at one end. The actuator module is located in a low pressure environment and each shield of the first plurality of cables is grounded. The transmission cables electrically connect the first plurality of cables with power supply, and include an extra cable configured to connect each shield of the first plurality of cables with the first extra cable, via a choke so as to provide a return path for common-mode currents.