Travel insurance carriers often provide useful travel information on their website or blog. Travel Guard recently posted a story about what destinations do not require power adapters for US travelers. The following is an excerpt from the blog post.
Travelers won’t need adaptors in countries that have a close relationship with U.S., like Puerto Rico and the U.S. Virgin Islands, although some countries that were once U.S. territories, like the Philippines, use their own wiring. In fact, most of the Caribbean uses American outlets, so beach vacationers can stay connected and share pictures with their families back home.
Most of North America also uses U.S. wiring, so short trips to Canada or Mexico won’t require an adaptor. Much of Central America uses U.S. adaptors as well, although Guatemala is a notable exception. In South America, countries like Columbia and Venezuela won’t need adaptors, while Brazil uses a mix of American and European outlets.
There are also a few scattered countries around the world that use the U.S. standards, like Japan, Liberia, and Taiwan, while some countries, like China, use a mixture of U.S. and UK outlets.