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**Naptown**View PostIf the voltage to ground is 120 and the current in each LN conductor is 14.1, balanced, the power will be 120 x 14.1 x 3, which is also the same as 208 x 14.1 x sqrt(3).

If your 14.1 is the current in each phase-to-phase load, the power is 208 x 14.1 x 3, but the line current will be greater than 14.1 by a factor of sqrt(3).

Now that you have watts, I will let you figure out the watt-hours, since you did not tell me the time factor.

BTW, I find that the trick of multiplying the phase line current times the line to ground voltage and then multiplying by 3 is really easy to remember and gives the same result as the "official" calculation. If nothing else it is a good reality check that you got the other formula correct.

There is no need to work with vectors and sines and cosines, since the amount of power going out the phase lines will be exactly the same for a given current regardless of whether the load is actually delta or wye. You just have to keep in mind which current you are measuring.

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