What is the advantage of starting with 480V in this context?

• A. The amperage capacity of the cable up to the transformer is significantly higher
• B. The amperage capacity of the cable after the transformer is higher
• C. Voltage is higher at the load
• D. Power is higher

Answer: (A)

The main idea is that increasing the voltage you use to feed equipment lowers the current needed for delivering the same amount of power. Since power equals voltage times current (P = V × I), doubling or tripling the voltage means the current can be reduced proportionally for the same load.

So, feeding the transformer with 480V means the cable feeding that transformer carries less current than it would if you used a lower voltage. That lower current reduces heat and voltage drop on that upstream run, giving the feeder more headroom in its ampacity for delivering the same VA to the transformer. In other words, you can meet the same load with less current in the feeder, which is the practical advantage.

The load side of the transformer is determined by the transformer ratio, so the voltage at the load isn’t inherently higher just because the input is higher, and the total power transferred isn’t magically increased—aside from the usual losses.