Code question

[yaoyaodes]

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.

 

[main197]

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.

 

[yaoyaodes]

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.

 

[salmanshu322]

clearly mention that 277V is single phase connected across L-N.