Reliable performance Vacuum-pressure impregnation is used to re-enforce the electrical insulation of the ballast, preclude moisture, inhibit noise, and dissipate heat;Pre-insulated voltage leads reduce the risk of shock and shrink installation time The basic ballast is the open core and coil which is most often used as a component within a lighting luminaire. The core and coil also forms the nucleus of Philips Advance's five other ballast configurations. Vacuum-pressure impregnated with a silica-filled pol