Originally Posted by camper_Lucy
reverse polarity in a DC system will destroy batteries and electronics.
Nobody - obviously - said anything about DC voltages. AC voltage polarity, if reversed, does not damage an appliance. Helpful is to read what was posted before making irrelevant denials.
Again, everyone who uses the phrase "surge protector" also should be describing which type. Different devices are all called "surge protector". For example, a line conditioner that compensates only for minor low voltages does nothing for potentially harmful low voltages. Some even call that a surge protector. Another surge protector for microsecond spikes (that might damage electronics) may also melt or smoke when exposed to lower but excessive voltages. Too completely different anomalies. That protector only addresses one.
A common protector (listed by manufacturer name) simply disconnects power when voltage goes slightly too low or too high. A switch. It may or may not also contain another device (also called a surge protector) for high voltage spikes that might damage electronics. The phrase "surge protector" is a blanket descriptor for different devices.
Use of 'surge protector' that does not specificaly state which anomaly is insufficient information. Even some electricians (who learn how to connect wires - not how electricity works) may not know this stuff.
A typical "surge protector" for campgrounds will disconnect AC mains when voltage goes slightly too high or low (potentially harmful to electric motors - not electronics). It might report some 'safety' ground defects. It cannot report any defective 'earth' ground.
It might also report reverse polarity. Reverse polarity (nobody was discussing DC polarity) does not harm appliances or create a fire. But suggests a campground electrician may have created other mistakes (ie improperly wired pedestals) that you do not want to learn about the hard way. An electrician must be quite careless to reverse polarity.