With Leitungslängenberechnung you can calculate the minimal needed cable cross-section for a specific lenght.
Specify the maximum current and the used voltage in order to get a valid result — do not forget to switch your brain on when using this tool, as there might still be bugs.
Also have a look at the tab Ausschaltbedingung.
Make sure you have installed .NET Framework 4.5 on your windows computer in order to run the program.
This software is provided “as is”, distributed under the terms of the MIT License.