So, it sounds like there are two common wiring methods for 75KVA (480V/Y208V) transformers as far as the OCPD sizing.
1) Primary OCPD - 90A Secondary OCPD - 200A
2) Primary OCPD - 125A Secondary OCPD - 300A.
If inrush current was not a factor, what factors make one choose between the two? And the factors change the primary or secondary OCPDs? And What is the rule to size the secondary OCPD once the primary OCPD size is determined?
1) Primary OCPD - 90A Secondary OCPD - 200A
2) Primary OCPD - 125A Secondary OCPD - 300A.
If inrush current was not a factor, what factors make one choose between the two? And the factors change the primary or secondary OCPDs? And What is the rule to size the secondary OCPD once the primary OCPD size is determined?