The type C plug is built with two round pins and is a general 230-volt plug commonly used in most European countries. Currently, it is the base standard in all of Europe with the exception of Malta, Cyprus, Ireland and the U.K. However, there is a move by most European countries to phase out this type of plug due to its lack of grounding. Grounding is a process to redirect excess electricity and dissipate it to avoid overloading. A plug with a third pin in the middle, slightly on top of the two main pins, is the grounding pin, also called an earth conductor.
The Type E plug is designed with two round pins and a small grounding hole on top. This type of plug fits into a socket with a grounding pin protruding. This is a standard 230-volt plug used in Belgium, France, Slovakia, the Czech Republic, and Poland.
Used in Germany, Sweden, Portugal, Spain, Finland, Norway, the Netherlands, and in other eastern European countries, the Type F plug is designed with two round pins with a grounding clip at the top and bottom. The socket designed for it has two short metal grounding contacts to fit into the clips of the plug. It is often referred to as the Schuko (an acronym of a German word that means grounding) plug, due to its unique grounding design.
The Type G plug is the standard plug used in the U.K. and Ireland. The plug is designed with a vertical grounding pin on top of the two horizontal primary pins. This particular plug is considered the safest plug due to its grounding design that uses three wires instead of the traditional one-wire configuration. The only drawback is that the design results in a very bulky plug.
Exclusively used in Switzerland and Liechtenstein, the Type J plug has a similar design as that of the Type C plug. The only difference is the third grounding pin exactly at the middle in a slightly elevated position.
Greenland and Denmark use the Type K plug exclusively. The design of the plug is similar to that of the Type F plug, featuring two round pins. However, Type K has a bottom-located grounding pin instead of Type F's top and bottom grounding clip design.