Illinois Electrical Porcelain Company timeline
unknown start date - pre circa 1915
circa 1915 - circa 1919
circa 1919 - circa 1924
Illinois Electrical Porcelain Company timeline
Illinois Electrical Porcelain Company timeline
1925 - 1935
1937 - 1940
1953
1954 - 1958
Illinois Electrical Porcelain Company timeline
Illinois Electrical Porcelain Company timeline
Illinois Electrical Porcelain Company timeline
Dry processed, 3-piece molds, skirt & petticoat fire rested.
Ink stamped, no mold lines, skirt & petticoat fire rested.
Incuse with "dot codes" and the addition of model number "237"
Incuse "Date/State/Model" marking.
Ink stamped "Date/State/Model"
Incised on skirt "Illinois/1953"
Purchased by McGraw Elect. Co. in 1953. Line Material Co. (a subsidiary co.)ran the
Macomb Ill. plant and incised markings "IEP/1954" which still represented "Ill. Elect.
Por.". In 1958 Thomas A. Edison Ind. merged with McGraw and though the "IEP"
marking continued the "E" now stands for "Edison".
1940 - 1953
Just guessing these markings are transitions from the dated ink
stamps after 1940 to the dated incused mark from 1953.