Inrush current for transformers

[faresos]

SQD recommend to use larger size breakers for the primary protection to the transformers. Examples:

Square D?s recommended breakers are:

- 112.5kVA - 250AF 250AT Type J breaker with instantaneous set at 10

- 225kVA - 600AF 500AT Type LC breaker with instantaneous set at HI

My question is, since we are upsizing the breakers for the inrush, do we have to upsize the wires?

Thanks,

 

[don_resqcapt19]

Yes, the transformer primary conductors must be protected at or below their ampacity.