2017 NEC Example D3(a)

[johnson151]

I've been doing the example problems in the back of the book, and on D3(a) I'm confused as to why they didn't use 1.73 multiplier when calculating the welders but did use it when calculating the motors? Any insights would be greatly appreciated!

 

[infinity]

The welders in the example are single phase and the motors are all three phase. For the three phase calculations the factor 1.73 is always multiplied by the voltage.

 

[johnson151]

Interesting, I guess I assumed 480v meant 3 phase, but now looking at the problem I see that they've spelled out what's 3 phase. It's always in the fine print! Thanks for your help!

 

[infinity]

Interesting, I guess I assumed 480v meant 3 phase, but now looking at the problem I see that they've spelled out what's 3 phase. It's always in the fine print! Thanks for your help!

Yes it's 480 single phase for the welders in the example.