Inconsistent wire sizing

[auto99]

when I click the wire and then properties, this is what it shows. The wire size should be #12 and not #6.  Where does Revit gets #6?  I cannot change it either, it is grey.

Also, why I cannot change the number of grounds and neutral to 0?  I can change the Hot Conductors, but neutral and ground always come back to 1 even if I change them to 0. 

[pteague]

I have had the same problem.  Revit doesn't seem to calculate the wire size correctly at all.

[MikeDabbas]

this because of voltage drop, the circuit is probably long, if you go to your wiring settings, you will notice that Max Voltage Drop for Branch circuit is 2%, if you circuit is long, Revit will do the math for you and upgrade the wire to achieve this voltage drop value...