There are "Surge protectors" and there are SURGE PROTECTORS!!!
I have both. the first protects against only one thign (Spikes in the voltage short term transisent spikes that can easily hit 1000 volts often happen when an A/C kicks in or out)
The other SURGE GUARD protects against high voltage (Surge) Low (Dip or brown out) some do off frequency, Open neutral 240 volt 30 amp outlets and more.
Progressive Insudtries makes both types but the HW 50/30c are the best (the 50 ois for 50 amp rigs. you can figure out the 30)