50A to 15A RV Power Adapter Cord Plug [NEMA 14-50R Female to 5-15P Male] [Dogbone Style] [EZ Grip] [Max 1875W @125V] [ETL Approved] [LED Indicator] [10/3 STW Cord w/ Copper Wires] for Trailer Camper

Gotcha, thanks for the detailed explanation, much appreciated. I dont need 240v though, only 110v and realistically only be drawing under 5 amps, if that, it's just to keep the batteries topped up and use the lights if I need to. I guess what I'm trying to do is the same thing the 50a to 15a adapter does but inside the box rather than using an actual adapter. They're cheap enough but the reason I want to stay away from the adapter is to keep it clean and under the waterproof lid of the receptacle box. I guess I'm trying to do this adapter inside the box.