Thanks, I should have kept reading the section but there is a section for <25' secondary conductors.
But, does anyone have the 2014 NEC handbook? Transformer section 240.21(C)(2) commentary gives a transformer example and says to apply section 240.21(C)(2) (transformer secondary not over 10’) to determine minimum secondary conductor size. But the example, applies 1/10th rating of the primary OCPD which has nothing to due with the rules of section 240.21(C)(2). Unless I’m reading this wrong, is this commentary not correct??