Voltage and frequencies world wide
The following section provides a detailed list of single-phased network voltages divided into voltages and frequencies of the various countries and the plugs and power outlets in use in these countries. The list includes all details. As a rule of thumb, the following voltages and frequencies can be assumed:
 110-120V/60Hz countries:
North America, Venezuela, Columbia, Ecuador, the northern Caribbean islands (Cuba, Haiti, Dominican Republic, Puerto Rico, Virgin Islands, Bahamas), Taiwan and South Korea.

100-110V/50 and 60Hz:
Japan

220-240V/50Hz:
most other countries

 Information about electrical systems in industrialized countries are reliable and easy to get. Information about developing countries are scarce, often incorrect and difficult to verify. In addition, such information can be absolutely irrelevant because, e.g. specific medical equipment or computer systems can be supplied by independent gensets. Finally, voltage and frequency fluctuations, which are within tolerances in industrialized countries, are something which can be dreamed of in countries, where power is often available for only  4 – 5 hours a day. The data given in this section are therefore, especially for developing countries, vague, because in some of these countries there are up to five different plug types in use. For these countries, there are either no standards at all, do not apply to plugs and power outlets or are simply not observed by the local market. It is not unusual when there are different voltages and frequencies in use in particular countries. Some towns – sometimes even particular buildings – are supplied with different voltages and frequencies. Most third world
systems are not earthed so that earthed plugs are useless for earthing.

The power data are subject to a tolerance of up to 10%. In some developing countries these deviations are even higher.