Most of Peru uses 220V, 60Hz. Talara uses a mixture of 110V, 60Hz and 220V, 60Hz. Arequipa uses 220V, 50Hz. Most outlets are Type A and Type C, that is they will accept either plug, however sometimes they will either be Type A or C and will not accept the other style. It's uncommon to find grounded outlets Type B but you may come across them occasionally. It's not recommended to adapt a three pin plug for use in a two pin outlet.
Although Peru has rich natural resources and many great places to visit, the poverty scale reaches 25.8% of the population. The rich, consisting mostly of a Hispanic or "Criollo" elite, live in the cities. Nevertheless, most Peruvians are great nationalists and love their country with pride largely stemming from Peru's history as the hub of both the Inca empire and Spain's South American empire. Also, many Peruvians separate the state of Peru and its government in their minds. Many of them distrust their government and police, and people are used to fighting corruption and embezzlement scandals, as in many countries.
The Peruvian economy is healthy and quite strong, however inequality is still common. It is indebted and dependent on industrial nations, especially China, Russia and United States. The US foreign policy decisions in recent years has contributed to a widely held negative view about the US government in Peru, but not against individual citizens.
The word gringo is used commonly but is not generally intended as offensive. The original meaning encompassed all white people who do not speak Spanish. Many people use the word gringo exclusively for Americans or American look-alikes. It's not uncommon for blonde people to be called gringo. Peruvians do not hesitate to greet you with "¡Hola, gringo!".
Generally, people are very friendly, peaceful and helpful. When in trouble, you mostly can rely on getting help. But as with any setting, it is always good to watch out for yourself and try to avoid bad situations. If you get into an argument, it is a good idea to remain amicable, but firm. Most of the time, you can find a compromise that satisfies everyone.
Peru is not exactly a haven for efficiency. Do not expect things to be on time, or exactly as they intend to be. Outside of the more upscale tourist services and big cities like Lima, English is uncommon and the people, trying to be friendly, can give wrong or inexact advice, a translator can always be helpful in this cases. Plan ahead and leave plenty of time for travelling.
You may also want to see Tips for travel in developing countries for some useful hints.