The BAL 500 fluorescent emergency ballast works in conjunction with the AC ballast to convert new or existing fluorescent fixtures into emergency lighting. The emergency ballast consists of a high-temperature nickel cadmium battery, charger and electronic circuitry in one compact white case. The BAL 500 can be used with one 17 W through 40 W (2' - 4') T8, T10, or T12 fluorescent lamp without integral starters, including U-shaped, HO, VHO, circline, energy saving, and (4-pin) long compact. It is also compatible with most 1, 2, 3, and 4-lamp electronic, standard, energy saving, and dimming AC ballasts. If used in an emergency-only fixture, no AC ballast is necessary. This ballast is not suitable for use in air handling heated air outlet fixtures, and wet or hazardous location fixtures.