Dumb electrical question.....

[Gregger]

My question as follows: Due to the IBC or local code inspectors want to see the volt amp loads on my panel schedules. It's been a very long time since I've done this and I have a brain cramp. If I have say a 6000VA, 208v, 1ph hot water heater do I show 3000va on phase A & B or 6000va on both phase A & B? Thanks!!

 

[Art]

My question as follows: Due to the IBC or local code inspectors want to see the volt amp loads on my panel schedules. It's been a very long time since I've done this and I have a brain cramp. If I have say a 6000VA, 208v, 1ph hot water heater do I show 3000va on phase A & B or 6000va on both phase A & B? Thanks!!

probably doesn't matter...but I always show 1 load, 6000VA in this case...the load is not associated with the conductor, per se, but with the device (water heater)...

the current is the same in each leg, and the V drop should be <3% or so, ~6VAC in this case, or 3VAC per leg...

so 'technically' the VA of each conductor leg is 3V x (6000VA/208V) ~ 87VA...

 

[geofs_PE]

I believe that you would assign 1/2 of the total VA to each phase. If, for instance, you were to connect 3 such loads of 6000 VA to a 208/120 wye secondary, #1 between A-B, #2 between B-C, and #3 between C-A (see attachment). If you attribute half of the 6000 VA to each phase it is connected to, then phase A would have 3000 VA from #1 and #3, phase B- 3000 from #1 and #2, and phase C- 3000 from #2 and #3, for a total of 6000 per phase and an overall total of 18,000 VA.

In this case, you would still get the same result if you simply assigned the entire #1 VA to phase A, #2 to B, and #3 to C. However, if your loads weren't equal and balanced across all three phases, assigning the entire load to one or the other phase would result in incorrect VA/phase totals.

Panel_Schedule.pdf