I am actually working in a panel shop. We do not install the panels themselves, we just build them to spec. But these panels I speak of, they have a controller that runs on 240v, but the practice has been to wire the panels with a black for L1 and a White for L2. We have had customers request that we change the White wire to a black. The only justification I can get for the white wire is that it is a grounded conductor.
I wish I could share the schematics, but I am only an employee here and do not want to cross any lines. I am really asking these questions so I can bring a valid presentation to my employer if anything is askew.
Thank you all...