MV Switchgear - IEC 62271

The size of the internal earth bus (the bar running through the entire switchgear lineup) in my current project differs from the size indicated in the type test report. Is this acceptable? Is the busbar size specified in the type test report applicable only to the main busbars, and not to the earth bus? If the manufacturer provides calculations demonstrating that the earth bus size is adequate for the specified fault current and duration, would this be considered acceptable? For example, if the short-time withstand current/duration is 25 kA for 1 second, and the adiabatic equation indicates a required conductor size of approximately 175 sq.mm, would providing a 200 sq.mm earth bus (40 × 5 mm) be acceptable in this case?

Can the branch earth bar size be different from the main earth bar? In the type test certificate provided by the manufacturer, the same earth bar size was used for both the main earth bar and the branch earth bar.