All the scopes that I have seen state the maximum input voltage around the BNC socket. On mine it says 300 Volts PP+DC, This seems to be the voltage level on most scopes or at least all the ones I have looked at, the only time I have seen different was on a USB scope and that was 5 volts only, which is one reason such scopes are useless. I presume that as the maximum Volts/Division on my scope is 5 volts that the 300 volts PP must be the protection level, after all you can use a 10 or a 100 times probe and go to kilovolt probes as well.