Martin Schmid has been sharing some deeper insight into the "magic" behind electrical calculations that Revit provides. Every engineer I've met is, not too surprisingly, skeptical about trusting yet another software for these answers. There has been data, in help documentation, to support the results but not quite as deeply as the last three posts combined. Check them out!
Why do I get different Voltage Drop results with Revit compared to the NEC?
To compute Voltage Drop, why does Revit use the formula VD=(L*R*I)/1000?
Why does the Revit Wire Impedance Factor table have separate sections for Three Phase and Single Phase?