Transformer Coordination

I guess it depends on the location of the transformer in the system...

..."Properly engineered systems will allow only the protective device nearest the fault to open, leaving the remainder of the system undisturbed and preserving continuity of service."...

Read more...

Additional info....

https://forums.mikeholt.com/threads/difference-between-power-and-distribution-transformers.133743/

A transformer is not end equipment, as it has electrical circuits both in and out. Coordination and selectivity passes through a transformer, no matter where or how big it is. If your transformer is a lamp ballast with no secondary overcurrent protection, then you do not and cannot provide selectivity.

Recently I attended a webinar, in which the trainer said, coordination is not required as the primary and secondary voltages are different and as such transformer should be treated as "end" equipment.

Er, um, is this thread about regulation and best practice, or is it an opinion poll, please?

Only, prospective contributors might like to know that before responding to it.

That is so wrong, you may have misunderstood the statement or context. It is somewhat difficult to coordinate protective devices across a transformer, your available fault current is limited by the transformer impedance, the winding configuration can alter the types of faults that can be sensed in the primary, and the fault current is altered according to the transformer ratio, but these effects can be calculated with reasonable accuracy, certainly good enough to provide good selectivity and coordination.

Consult a qualified local Electrical Engineer.