Comprehensive and scaleable bus and breaker fail protection for LV, HV and EHV busbars. The B90, a member of the UR Family, features integrated protection and breaker failure for re-configurable LV, HV, EHV multi-section busbars up to 24 feeders. Use one or more B90s together to build a sophisticated protection system that can be engineered to meet the specific application requirements. The B90 performs fast and secure low impedance bus protection with sub-cycle tripping time averaging 0.75 cycles.