GE 2-Bulb Contractor Residential Grade Electronic Fluorescent Light Ballast, 4 Count GE residential grade electronic ballasts are residential grade using only 120 volt. Their feature rapid start and electronic ballast. Replace your magnetic ballasts with GE electronic ballasts that use less energy. Use this GE 240RES120 electronic ballast in T12 (1-1/2-inch diameter) 2-bulb residential fixtures that are designed for F40T12 48-inch fluorescent bulbs.