Why all the different continents of the socket?
When it comes to electricity, you can forget about globalization. Even in the European Union, where one currency goes, there are different electrical outlets. Therefore, going abroad, it is necessary to replenish baggage adapter or search for it already upon arrival. The reason – the historical factor.
In the era of electrification of the inventors of different countries offered their own variants of the best outlets; around the world to build different types of power generators. A national company responsible for the installation of electricity, supplying their devices that are suitable for these networks. Accordingly, different types of plug connectors and outlets were introduced and their networks were designed. Development of other countries were completely ignored.
Influenced the development of outlets and availability of materials. For example, during World War II in the UK, a three-stitch plug with a short copper fuse was invented. Such a design allowed to save copper stocks for military needs.
According to one classification, 12 types of sockets are distinguished, according to another – 15. And the sockets of the same type sometimes take the forks of another. In this case, in different parts of the light, the voltage and current frequency may vary
Now, according to one classification, there are 12 types of outlets, according to another – 15. And the sockets of the same type sometimes take the forks of another. However, learning that in the country where you are going, the same type of outlet, like at home, do not rush to rejoice! This solution is only half of the problem. In different parts of the light, voltage and current frequency may vary.
Classification of types of sockets and forks in different countries of the world

The most common two standards are the most common: European – 220-240 V at a frequency of 50 Hz and American – 100-127 at a frequency of 60 Hz. Do not check what will happen if an electrical appliance, operating from 100-127 V, is included in the outlet from 220-240 V.
In some countries, you should keep the Ear East. For example, in most Brazilians, 127 B is used, but in the north of the country there are 220 V. And in Japan, the voltage is the same everywhere – 110 V, the frequency is different: 50 Hz is used in the east, in the West – 60 Hz. The reason is simple: first for Tokyo purchased German production generators with a frequency of 50 Hz, and soon after that in Osaka put American with a frequency of 60 Hz.
Perhaps someday will be adopted a single standard. Universal socket for all types of forks has already been developed. But while everyone is the case – install it or not. In addition, you must first come to a single voltage standard. And it rests on the huge financial costs for re-equipment and re-equipment of transformer substations, replacement of outlets and forks.