The whole electric system of Peru is of 220 volts and 60 cycles.
Some hotels of 5 and 4 stars have additionally electric systems of 110 volts.
Take the caution of verifying the voltage of hair dryer, razors, sound systems, loaders of batteries of notebook computers, video camera recording, etc.; most of these equipment at the moment are auto voltage.
If it is not this way, it will require a transformer 220 / 110 volt for its correct use in Peru. It is very common to find this type of transformers at the stores in Peru.