We have a few State Parks in southern Georgia we visit which has 2, 30 amp plugs in the pedestal. My adapter has 2, 30 amp male ends which allows us to run the entire coach on electric without a low voltage issue.
I have tried to use it at some Florida SP that only have a 30 and 20 amp plug. It will trip the GFCI on the 20.
When we had our fiver with 30 amp line but 2 A/C units. I used an extension cord hooked to the 20 amp and a dedicated circuit to our bedroom A/C. It worked like a charm everywhere we went. I have a friend that unhooked one of his A/C units from his wired 50 amp service and dedicated its power through an extension cord to the available 20 amp to get around our southern heat with both A/C units working.