Lighting Inverters are special use Uninterruptible Power Systems [UPS]. They provide uninterrupible power for emergency lighting. Emergency lighting is mandated by LAW [National, State and local electrical codes and the NFPA Life Safety code] to provide continuous and adequate illumination for a minimum of 90 minutes. The lighting loads may be a combination of incandescent, fluorescent or metal-discharge sources that have unique load and power factor characteristics. Some lighting sources, such as metal-discharge, may have a long re-start time if the power is interrupted for even a brief few cycles.