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yaoyaodes

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problem: Calculate the minimum size of TW type copper conductors required to feed a 45KVA 3 phase continuous load from a 480V/277V 3 phase 4 wire power distribution board. The temperature rating of equipment terminals is 60 C( 140F)

The solution uses 45K/(sqrt 3*480) to calculate the ampacity. My question is that should we use
45K/(sqrt 3*277) ? I assume that the load is connected to the 277 side.
 
277V is single phase connected across L-N. The question clearly states that it is a 3-phase load, so you use 480V. Looks like you're struggling with basics. If you have any reference book on basic electrical, you should go through it.
 
277V is single phase connected across L-N. The question clearly states that it is a 3-phase load, so you use 480V. Looks like you're struggling with basics. If you have any reference book on basic electrical, you should go through it.
Thanks. I thought was a transformer in the beginning, my mistake.
 

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