Plug F, known as CEE 7/4 and commonly called "Schuko plug", which is the acronym of "Schutzkontakt", a German word meaning "earthed/grounded contact". The plug was designed in Germany shortly after the First World War. It is similar to C except that it is round and has the addition of two grounding clips on the side of the plug. It has two 4.8 mm round contacts on 19 mm centres. Because the CEE 7/4 plug can be inserted in either direction into the receptacle, the Schuko connection system is unpolarised (i.e. line and neutral are connected at random). It is used in applications up to 16 amps. Above that, equipment must either be wired permanently to the mains or connected via another higher power connector such as the IEC 309 system. In order to bridge the differences between sockets E and F, the CEE 7/7 plug was developed (see photo above). This plug, which is shown above, has grounding clips on both sides to mate with the type F socket and a female contact to accept the grounding pin of the type E socket. The original type F plug, which does not have this female contact, is still available at the DIY shops but only in a rewireable version. A type C plug fits perfectly into a type F socket.
The Russian Federation uses a standard plug and socket defined in Russian Standard Gost 7396 which is similar to the Schuko standard. Contacts are also on 19 mm centres, but the diameter of this contact is 4.0 mm compared to 4.8 mm which is standard in Continental Europe. It is possible to mate Russian plugs with Schuko outlets, but Russian sockets will not allow to connect type E and F plugs as the outlets have smaller hole diameters than the pins of those two plugs mentioned. Many official standards in Eastern Europe are virtually identical to the Schuko standard. Furthermore, one of the protocols governing the reunification of Germany provided that the DIN and VDE standards would prevail without exception. The former East Germany was required to confirm to the Schuko standard. It appears that nowadays most if not all of the Eastern European countries use the Schuko standard.
Countries Using Type F Electric Plug/Socket - Algeria, American Samoa, Aruba, Austria, Azores, Balearic Islands, Bosnia, Bulgaria, Cape Verde, Chad, Croatia, El Salvador, Finland, France, Germany, Greece, Guinea, Hungary, Iceland, Indonesia, Italy, Jordan, Korea, Laos, Luxembourg, Madeira, Monaco, Montenegro, Mozambique, Myanmar, Netherlands, Netherlands Antilles, Niger, Norway, Portugal, Romania, Serbia, Spain, Suriname, Sweden, Turkey, Uruguay.