A poor ground might be the cause, either in the trailer or external. Not likely, but worth looking at.
Since the campground found a bunch of high readings, we expect it is not us. Also, I don't have a clue how to check for a poor ground! Would you like to explain how, please? Wouldn't the EMS tell us about a bad ground?
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Cathy. Floating Cloud
"Live in the sunshine, swim the sea, drink the wild air.... "
Emerson