Ok if you plug in like this
Park--Surge guard (See note)---Hughes---RV
Note: and the surge guard is one of the good ones that cut you off if the voltage is too low or high.. IT will cut you off when the uncorrected voltage goes too low (i think 109)
If you plug in like this (As I do)
Park---Hughes---Surge guard--RV
Then well if you plug into 220 volts by accident (using an adapter if needed) you will fry the hughes (or may fry it) but low voltaeg will be corrected BEFORE the surge guard cuts you off.
And that is why I do it that way .