it will see higher and lower voltages. got to see it first hand. when i got to this guys house he had 60 volts on one phase and 180 on the other. it would change with the different loads put on each phase. when i shut off his main everything was normal as far as measuring the voltage from phase to phase and from phase to ground. turn on his breaker and the voltage varied. thought it was a bad main breaker so i changed it. still the same. power company came and fixed the center tap on their wire at the pole and everything was normal. he still needs a new ground but won't here of it. so we wait for the next time it happens to him so that he can buy all new electronic.