If I want to know the maximum amperage per phase on a 30 amp 3 phase breaker, don't I say 30 X 1.73 = 51.9 / 3 = 17.3 maximum amps per phase? Thanks
If it's a 225 amp panel, then I assume the total allowed current per phase is 225A. Thus if you have 14 breakers, the total current of the breakers should add to no more than 225A per phase. Therefore you couldn't have all breakers be 30A. The average current should be no more than 16A per breaker phase.Again, I need some education. A 42 pole 225 amp 3 phase panel will accommodate 14 3 phase breakers. If all 14 breakers are 30 amp this will be 420 amps. I guess this means that the 225 amp panel can handle 225 amps per phase making it capable of handling 675 total amps not taking into consideration the 80% rule?? Again, I'm still learning. Thank you guys for helping.
Not necessarily true. There are de-rating factors used to calculate the size of the panel needed, or going the other way, calculating the load you can put on a panel of a certain size. It really depends on what will be running at full load for how long with what ever else is running. You could have 420A per phase on a 225A panel just in circuit breakers. However, if somebody didn't realize that all of those loads could be on at the same time when designing the electrical installation, the panel main breaker (if used) will trip.... Thus if you have 14 breakers, the total current of the breakers should add to no more than 225A per phase. Therefore you couldn't have all breakers be 30A.
225 amps per phase is not 675 total amps. Your error is not considering or understanding phase displacement, which impies angular, or vectorial additions.Again, I need some education. A 42 pole 225 amp 3 phase panel will accommodate 14 3 phase breakers. If all 14 breakers are 30 amp this will be 420 amps. I guess this means that the 225 amp panel can handle 225 amps per phase making it capable of handling 675 total amps not taking into consideration the 80% rule?? Again, I'm still learning. Thank you guys for helping.
by Jake Hertz
by Jake Hertz
by Jeff Child