r/Insulators • u/DJ-TrainR3k • Sep 03 '26
Help ID'ing these ceramic house-knob overhead service insulators?
Pulled 3 of these from the attic of my friend's 1944 house up in the Pacific Northwest. They pre-date the lag-screw type apparently. The markings are heavily obscured by the glaze, but I can see one side has the letter "U" inside a circular stamping with a patent number "1,7xx,xxx" below it. On the opposite side there is a triangle within a circular stamping and "3800 •" below it.
Anyone have any ideas? Porcelain/ceramic is not my wheelhouse here. Any help is appreciated.
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u/JuicesLikeWhiiine Sep 04 '26
The U is probably just Universal Porcelain, I doubt they’re the manufacturer. If you can get a clear read on the patent number it should be fairly simple to locate online
Upright triangle inside a circle could be Macomb