Tie feeder breaker connection

[EEENGRX]

Due to PDC-2 not having an emergency Generator and its consequence when there is loss of power from the main grid. The need to implement a Tie feeder breaker between PDC-1 and PDC 2 and run cables. This is to enable power supply to the UPS fed from PDC-2 without having to depend or use generator.Take a look at the design of the one line here and let me know your thoughts if the primary bus is bad design per the KA- SC interrupting rating.