ok i dont do a whole lot with hooking up transformers outside of control equipment so i am kinda stumped with this little job in our shop, we are getting an axle test stand to run for acouple of weeks and i am currently working on the hookup and we just happen to have a 225kva 240-480 transformer laying around our shop. leftover from the previous tennants i guess. anyway, in the 05 book, table 450.3(b) lists primary protection as 125% and secondary not required, or primary as 250% with 125% on the secondary, which is easy enough to figure out, what is making me scratch my head here is where is secondary required, i plan on having it to cya with the equipment but my boss is trying to save some money and im trying to do this right. thanks, Rob