Commonwealth Edison (usually called Com Ed by Chicagoans) is an electric company in Illinois owned by Exelon Corporation. Commonwealth Edison serves the Chicago area. State nickname: Land of Lincoln, The Prairie State Other U.S. States Capital Springfield Largest city Chicago Governor Rod Blagojevich Official languages English Area 149,998 km² (25th)  - Land 143,968 km²  - Water 6,030 km² (4. ... Exelon Corporation is a giant electricity generating and distributing company headquartered in Chicago. ... Chicago (officially named the City of Chicago) is the third largest city in the United States (after New York City and Los Angeles), with an official population of 2,896,016, as of the 2000 census. ...

Commonwealth Edison's transmission lines operate at voltages of 69,000, 138,000, 345,000, and 765,000 volts. In the physical sciences, potential difference is the difference in potential between two points in a conservative vector field. ...