Cuba operates on 110-volt AC (60-cycle) nationwide, although a few hotels operate on 220 volts (many have both). Most outlets use U.S. plugs: flat, parallel two-pins, and three rectangular pins. A two-prong adapter is a good idea (take one with you; they’re impossible to find in Cuba). Many outlets are faulty and dangerous. Electricity blackouts (apagones) are common. Take a flashlight, spare batteries, and candles plus matches or lighter.
© Christopher P. Baker from Moon Cuba, 5th Edition