We went to a rally awhile back, actually parked the bus without hitting anything or anyone else (what we term as a 'good landing), and discovered that one leg of power was out.

Nice.

Come to find out, that one of the 50-amp prongs on our male plug from the bus was kinda corroded. Couple of scrapes with a knife on the corrosion and shazzam (technical term) both legs of power worked! Problem fixed.

When you do the step-down from 50-->30-->20 AMP connection, please insure that each individual prong is really clean and making a solid connection. If you think you may be putting some load on the circuit, feeling the connection. If it's hot, there's a chance it is either being overloaded (verge of popping a breaker) or there may be some corrosion in the connection.

Same goes for the female connections. MAKING SURE THE POWER IS OFF, an emery board or nail file while holding the connection upside down so the crud falls to the ground, clean up that little puppy.

Kinda surprising when you see the results. If your connections are cruddy, you may find increased voltage readings in your bus after cleaning.

I used Helen's nail file dealie and she never found out. Or at least, if she did, she didn't say anything: Yet.