I have a concession trailer that has a 220 plug. However, I have nothing in it that uses 220 right now. When I go to places I need to plug into 110 outlets. I can not find an adapter, and was told I would have to make one myself. Any idea how to do that, or know where I could find a diagram? THANKS

What you have is a breaker box that splits the outlets into two legs. You need to look and see if the AC uses 220 volts, if not then put both hot legs on the one hot of the 110 volt plug and then you have a ground and neutral. Wire a 110 volt plug into a small box where you put a receptacle for the 220 volt plug where the two hot legs go to the one hot leg off the 110 volt line. You will need the highest amperage plug and receptacle you can buy. It will work fine. DrTom4444