No...45A is correct.
Use 15 amp conductors and see how warm they get?
Or how long a 15 amp OCPD will hold.
37411 / 480 = about 78 amps, that is what it would be if it were single phase. Balanced three phase splits up and by factor of the square root of three, so divide that ~78 by 1.732 and you get your ~45.
...Yeah, it's just like single phase. With balanced single phase when one line current is at its maximum the same current is coming back on the other line. With balanced three phase when any phase current is at its maximum the same current is coming back split between the other two phases.Or I could argue 3 x 45A = 135A in which case I’d need #1/0 for the Branch ckt...
I know it doesn’t work that way. Each ph carries 45A and for load purposes it is still loaded as total 45A
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Actually you a little bit on the right track, you essentially have three 45A loads @ 277 volts = 37395 VA. close to same VA, rounding being the reason for differences. (480 x sq rt of 3 = approximately 277)Or I could argue 3 x 45A = 135A in which case I’d need #1/0 for the Branch ckt
I know it doesn’t work that way. Each ph carries 45A and for load purposes it is still loaded as total 45A
Sent from my iPhone using Tapatalk
Yes, if you look at a three phase waveform, whenever any of the traces is at its positive maximum the other two (plus and minus 120 degrees) are at their negative maximum divided by two. Similarly, if you look at a split phase waveform, whenever one trace is at its positive maximum the other is at its negative maximum.