Consider an alternative.
I put one of these in the side of my trailer, next to the power pedestal, or close to it. It could be in a slide, or not.
Inside, I put a regular house electric double receptacle. I wired the two together (although the walls are too thin for these two to be directly across from each other. They have to be offset).
Then I plug an extension cord into the 20a extra receptacle on the power pole. I can now plug any 120v device into that one receptacle and not be using any of my house amps.