Cost-effective, low-impedance, biased bus differential protection for up to six feeders The B30 features integrated protection, control and metering for MV, HV and EHV busbars, providing cost-effective, feature-focused busbar protection. Use the B30 to protect busbars with up to 6 feeders with up to two three-phase differential zones. The B30 is a cost-effective alternative to high-impedance schemes, ideal for breaker-and-half bus schemes, with integrated feeder backup protection and metering.