Originally Posted by Rick and Mindy
If I remember correctly, as explained by my electrician brother, there is a 10% acceptable variance for most appliances. Some appliances will actually tell you on their label what voltage is required. Too much voltage or too little voltage can cause damage. That would make sense since you stated that your progressive surge protector shut you down at 108volts (120 volts minus 10%). It will also shut you down if the voltage goes up to 132volts (120 plus 10%). They are made to protect everything and have saved me many times at campgrounds. When this happened to me at a State Park in Arkansas, the park technician tried to tell me to disconnect the Surge Protector and everything would be fine. I asked if he would pay for any damages if any occurred and of course he said "NO"!.
Rick you are 100% correct all items made for U.S.A. or Canada must be approved by some of these standards UL ULC CUL CSA.
All electrical items must have a variance of 10% high or low. And that goes for 120 - 240 - 277 - 347 - 600v.
The bigger problem is (IMO) low voltage. This is worse than over voltage as your equipment then starts pulling the power instead of being fed the power and it over works / heats up.
You can cause your own low voltage situation as follows. At the pedestal you have say 110v (all is good) but you are using a 100' 30a cord to feed your 50a unit. That 100' can cause an adtitional voltage drop caused by a long wire run of too small a gage.