A hot ground on an AC circuit can be caused by a bad wire tie connector.
The hot
ground leg of the AC outlet in my camper was quickly determined using a voltmeter.
The cause was a loose wire tie connector (shown in the image below).
A quick way of checking outlets is with an outlet tester like the one shown below:
Lastly, if you don't know what you are doing, you should quit trying to use an amp meter for troubleshooting. Perhaps you have some kind of newer high end meter with automatic shunting built in, but if not, you would be safer and more efficient using a volt meter.