CD #155 Armstrong DP 1 with the letters KPP in an oval to the left of the Armstrong name

The CD #155 in its various incarnations was produced by the millions by Whitall Tatum, and its successors; Armstrong, and finally Kerr. This particular embossing is rather interesting.

The letters KPP appear on only the CD #155; and only on the single mold set used in 1972 (date code 68::). At that time the change was being made from use of the Armstrong name, and molds with later date codes have the KERR name. It is also interesting to note that the molds marked KPP have numbers 1 to 19, with numbers 20 and above used on later KERR molds. The letters KPP are an acronym for Kerr Packaging Products, the official name of that branch of Kerr. Since at that time (1972) Kerr was the only supplier of pin-type glass insulators in the United States, the KPP insulators may be found on the lines of anyone who ordered CD #155 insulators manufactured that year.

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Disclaimer: All information presented here is accurate to the best of my knowledge. It is based on research, personal correspondence, interviews with reliable sources, site visits, etc. When speculation is made, it will be clearly stated as such, and any relevant information used to make statements, whether inductive, deductive, or purely tangential will also be stated. It is not implied that this information is definitive, or total. We are dealing with historical information that was not documented carefully, if at all. I encourage all corrections, comments, criticisms, etc. Please remember that the goal is to increase the knowledge of the insulator community.

Last updated Monday, November 25, 1996

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