If you were parked next to me we coudl test it, I can generate both a low and high voltage situtation in a manner that WILL NOT damage your RV I can also tell you how to protect the RV during testing in this message:
TURN OFF THE MAIN CIRCUIT BREAKER... Yup, that is how you protect the RV.
Now: What I have is a 3-amp Variable auto-transformer (Variac) it can output from zero to just about the cut off voltage of my Surge Guard. I have the means to add a few volts to that.. But it's only a 3 amp (So you have to turn off the main breaker of you will pop it's fuse)
Then you plug in the RV (Via an adapter) and a volt meter and dial in the voltages.. or slowly increase, or decrease the voltage till the Surge Guard "objects" and shuts you off... That's how you test.
Finally remove the variac to storage plug in and turn the main breaker back on.
NOTE: I got the Variac for testing Other stuff (You use them when you restore vintage electronics to service) but it works for this too. I have 2 of them.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times