Just get an old work plastic box, the one where the ears flop out when you tighten it down. Cut a hole with a multi tool or other saw to match the box. Scamp just uses Romex house wiring , I usually use 12 ga. You can tap into another outlet or go back to the converter. If you add a ckt. you can buy a breaker from a big box store. You can buy outlets with USB jacks in them for charging. They usually run about $20 but worth it. If used outside or near water you need a ground fault outlet or breaker.

Eddie