calculating three Phase Load

[dsmith411]

I'm working on sizing a three phase transformer 277/480 for some parking lot lighting which is going to run on 277v and the load they have give me shows on the panel that A-54.8 amps, B-40.17 amps, and C-52.46 amps. Do I size the transformer for all three phases added up which would be a total of 143.30 amps or do I size it for the average of all three which is 49.14 ?

 

[Smart $]

I'm working on sizing a three phase transformer 277/480 for some parking lot lighting which is going to run on 277v and the load they have give me shows on the panel that A-54.8 amps, B-40.17 amps, and C-52.46 amps. Do I size the transformer for all three phases added up which would be a total of 143.30 amps or do I size it for the average of all three which is 49.14 ?

Minimum transformer kVA will be leg with highest amps (A@54.8) times 277 times 3.