Unsafe outlet?

Is this in your RV or a nearby outlet? If the black and white are reversed and you plug in something with a case ground it could blow the fuse. If you have to ask I guess you shouldn't. That said, I have a 2 and ground (blk, white, and ground) underground line that runs for 500 ft to my 220 vac ditch pump. Once a year I need 110 in that outlet for an air compressor to blow out the lines. I use one hot and a ground to my compressor. However, I know what the dangers are and careful and know how it is wired. Probably should have put in a 3 and ground but too late now. For 15 minutes a year I am not going to put in another 110 volt line. JMHO.