The enclosed HVF circuit breakers are rated for voltages from 4.76kV up to 40.5kV, with withstand voltages up to 190kV and rated currents up to 4000A. The open frame HAF circuit breakers are rated for voltages from 4.76kV up to 24kV, with withstand voltages to 125kV and rated currents up to 3,150A.