ASC 91742031C 4P 120V LTG CONT 20A MECH-HELD W/ENCLOSURE All standard panels feature the ASCO 917 electrically operated, mechanically held lighting contactor. This contactor is specifically designed to be used for lighting applications, including metal halide, mercury vapor, quartz halogen, tungsten or fluorescent lighting. Because the contactor is mechanically held, the panels provide quieter operation with a longer life expectancy than electrically held contactors would allow. NEMA 1 enclosures are standard. NEMA 12 and 3R enclosures are also available.