Electrical plug and socket 2 pin was originally invented by Harvey Hubbell and patented in 1904. Hubbell's work is also a reference to the manufacture of plug and socket and by the year 1915 after its use more widespread, although in the years 1920s home and commercial appliances still use a screw-type lamp socket base Edison.
Then plug 3 pin was created by Albert Büttner in 1926 and obtain patents from German patent agency (ED 370 538), his work is known as "Schuko". But there is also the creator of this 3 pin plug, which is Philip F. Labre, during he was still studying at Milwaukee Vocational School (MSOE) and obtain patents from the United States on June 5, 1928. Anyone penenmunya, discovery 3 pin plug or plugs this is something that is very unusual, because the aspect of human safety, so that the plug or electrical outlet of this type became the standard in almost all countries to date.
Types of Plug and Socket
The types of plug and socket are classified based on the voltage and frequency used in a country, so it can be said there are only two types are based on this classification, namely:
• For voltage 110-220 volts at a frequency of 60 hz
• For voltage 220-240 volts at a frequency of 50 hz
There are also some countries that use the plug and socket for both, see the map of the use of voltage and frequency of electricity in the world below. (Click image to view larger map)
While based on the safety plug and socket are classified into:
• Without grounding, ungrounded. Usually for a 2 pin plug, and according to the IEC standard is a class-II
• With grounding, grounded. Usually for a 3 pin plug, and according to the IEC standard is the class-I
• With grounding and fuses, fuse and grounded. Usually for a 3 pin plug.
Based on the above classifications, then the plug and socket of each state may vary, and generally the type and standard of the plug and socket are:
