Cable Box Bushing Transformer Bushings Voltage Class – 1.1 kV Voltage Class – 3.6 kV Voltage Class – 12, 17.5 kV Voltage Class – 24 kV Voltage Class – 33/36 kV Voltage Class – 36 kV (For Use in Highly Polluted Atmosphere) Current Transformer Bushings Voltage Class – 22 kV Voltage Class – 36 kV Voltage Class – 36 kV (For Use in HighlyPolluted Atmosphere)