At this point in time the only supported wire sizing in Revit is AWG (American Wire Gauge).
This is stopping electrical engineers using the metric system from using the power of the Revit electrical functions.
On the Autodesk help site there is a full article on with the tables for the correction and impedance factors for the different wire sizes known in the USDM(United States domestic market)
https://help.autodesk.com/view/RVT/2019/ENU/?guid=GUID-0F801DCD-18CD-4B7A-A64F-D4D9E8A4CEA9#GUID-0F8...
If these tables would also be implemented for metric sizing, then this would allow for the use of the following:
- The parameter voltage drop can function properly
this does not function at all when working with any sizing table then in the help article above.
- Use the wire size functions as intended
because the voltage drop parameter does not work the calculations made when upscaling wiring due to the length of the wire does not function at all.
the sizing will automatically adjust when the rating of the circuit was to change
- use wire types as intended
there is no way to use the wire types as intended because wire size does not work, the only workaround is to use a text parameter to display the cable or make a list of all the wire type and wire size combinations with a list of hundreds of wire types as a result.
With the BIM way of thinking this would keep the information combined in Revit, and would minimize the chance for mistakes.