Revit 2018 enables you to modify an electrical circuit path for more accurate voltage drop calculations. You can choose to edit the circuit path by selecting Farthest Device, All Devices, or Custom and manually edit the circuit path.
You can manually adjust the offset (elevation) and position of the circuit path as well as set the default offset.
This enables designers to better capture design intent, enabling third party analysis tools to utilize the information for other analytical workflows, such as short circuit current calculations.
Take a look at the edit electrical circuit path feature overview video for more detail.
With Revit 2018 you can manipulate and define the intended circuit pathway for downstream analysis.
Check out the help files on Autodesk Knowledge Network to learn how to edit the electrical circuit path.