Embassy fluorescent ballasts allow the same fixture to be used for both normal and emergency operation. In the event of a power failure, the emergency ballast switches to emergency mode and operates one or two of the existing lamps for a minimum of 90 minutes. Each emergency ballast contains a battery, charger and invertor circuit in a single package. The emergency ballast can be mounted in the fixture wireway or on top of the fixture, and is UL listed for factory installation or retrofit applications.