The scenario
An electrical engineer preparing permit drawings for a new commercial building needs a feeder distribution SLD.
What is in this drawing
Read the decisions behind it.
01
Two-busbar arrangement (A/B) allows either feeder bus to be de-energized independently for maintenance.
02
800 A feeder breakers sized to protect bus cable; 200 A load breakers provide downstream discrimination.
03
Main CB at 2000 A provides bus-fault protection coordinated with upstream HV fuse on the 11kV side.
Add a bus-coupler breaker between BUS_A and BUS_B to enable N-1 redundancy.
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