Ballasts are necessary in all lighting fixtures equipped with an an arc source light bulb such as fluorescent, high pressure sodium or metal halide. A ballast essentially functions as a power converter altering the incoming electrical current to provide the proper voltage and amperage for operating a given light source. Additionally, the ballast or ballast kit controls the starting function of the arc source lamp by providing either a preheating function or a simple voltage surge as required by the light bulb for correct ignition. Ballasts are generally rated for a specific lamp type and wattage or in the case of electronic fluorescent ballasts for a range of acceptable lamp types. As a general rule lamp and ballast combinations should have matching specifications to avoid early lamp failure or other serious electrical system issues. Please consult with your Kelsun sales representative should you require assistance with correct ballast identification for your lighting installation.