Hello, this is my first post and I've been out of school for a few years and now working a job in my field at a distribution utility, but I'm just really rusty or green on a lot of things now that I'm being challenged. Seems like the simplest questions elude me! Anywho, I've been tasked with finding the primary conductor size for a new commercial facility. We'll have a 3-phase 1000kVA, 12470/480 V pad mount transformer. The conductor will be bored to the transformer. Never done the calculation before. My initial thoughts are: 1000 kVA = 46.30 Amps (√3)(12.47 kV) Do I take 125% of the amps to account for voltage drop as I have read somewhere? Which would lead me to approx 58A? However, both of those numbers seem low for such a large transformer. Moving on with my theory, would I then account 58A as the maximum conductor ampacity? Would I divide that by 3 to account for the ampacity of the 3 individual primary conductors (or by 4 to include the neutral wire)? Or is the 58A the required ampacity for each conductor? As I said earlier, the 58A looks like very small conductor ampacity for such a large transformer. I'm thinking I should get an answer around a 4/0 conductor or something. Please guide my thought process on this. Thank you!