Is the Southwire Voltage drop calculator wrong?

[wwhitney]

My guess is a bug in the calculator.

Pretty sure I've figured out the bug--in calculating Z effective, the formula should be Zeff = R * P + X * sqrt(1-P²), where P is the power factor. [Note 2 to Chapter 9 Table 9 uses sin(arcos(P)) as the coefficient of X, but sin(arcos(P)) = sqrt(1-P²) for 0 <= P <= 1.]

However, instead the calculator appears to be using Zeff = R * P + X * sqrt(1-0.9²). I.e. changing the power factor in the web from the default of 0.9 changes the coefficient of R, but not the coefficient of X.

Will figure out how to report this to Southwire.

Cheers, Wayne