Hi, I have one of those Progressive Industries units from Camping world. It is supposed to shut the system down if the voltage drops below about 105 ( I will have to look at the specs ). Also shuts off when too high, or if there is improper wiring. There is a remote gauge inside that shows the current voltage, amperage, cycles and any errors. It has a built in delay of about two minutes if the power shuts off. This allows the A/C unit to reduce its pressure before kicking in again. Works for me, Doug