The world is full of different kinds of electrical receptacles. There are at least 14 groups of different kinds of receptacles, and even within those groups there are deviations. Use of different kinds of receptacles is generally limited to specific geographical areas. Within the United States, for example, electrical receptacle configurations are almost exclusively limited to the familiar two or three-pronged NEMA outlets. They feature two flat slots parallel to each other and often, especially in the case of newer receptacles, a third, usually circular grounding contact beneath and between the two flat slots.
People who have lived in the United States their whole lives and who have never traveled outside of the country may be surprised to hear that electrical receptacle configurations vary widely from country to country. Even within countries, especially in the case of post-colonial countries, it is not uncommon to see more than one configuration present in different places. Why so many different receptacles?
It turns out that it’s not an easy question to answer. Also, there seems to be more than one explanation for the large variety of receptacles worldwide. After all, why is it necessary? Wouldn’t it be simpler to just share the same design worldwide? Let’s tackle the easy answer first. Post-colonial countries inherited the receptacle designs of their former colonial powers. It would be expensive to switch now, and there’s really no reason to (that is, unless the world decided to adopt a universal standard). As for the powers themselves, there are a few possible answers. Some say that it was for nationalistic reasons that within Europe there were developed so many different receptacle varieties. In other words, no one could agree. Another answer, which may be less credible, is that people were more attracted to certain designs visually, and so they kept them for that reason instead of for reasons of efficiency or safety. In the end, there probably is no single answer, except this, maybe – carry an adapter when traveling.