Hi,
I see you are in a 30 amp RV. Take the unit back for a refund. You do not need it. 50 amp rv's DO need that sort of protection because they are on two "legs" of power, and if the neutral wire is loose or faulted in some way then lots of damage can happen.
For 30 amp that is not a possible scenario. Simply check the voltage and polarity before you plug in.
It may be better to look at surge protected autoformers, before using something that cripples the use of the electrical system by cutting off the power at what may be too low a voltage to prevent damage to electric motors. My comfort level is 109 volts or above.
Here is what I use:
kill-a-watt
watt meter
Outlet tester.
outlet tester