We had a electrician install a 250-125 volt, 30 amp socket,outlet4 prong male in our wellhouse,back in ,1999,this was never attachedto the wellhouse wall, there was no cover on it, this was just sitting, on the dirt floor,there is slight surface rust, on the back of the metal outlet, several years ago I wrapped,this up in heavy plastic, and put a brick under it, is this oulet safe? is there a way,to test, the outlet itself? we do know that, no moisture got into it,but concerned that dust or tiny bugs,may have compromised it? I will also call the electrician company that installed it,to ask there opinion. Since this is for a lot of electrical juice,I'm concerned. Any thoughts? thank you, for your imput. The face of the outlet,is normal,no rust or corrosion,just surface rust,on the back plate.