Expert: Bob Berry - 11/18/2011

Question
Hello Bob,

I have come across a porcelain insulator that I found in my garage.  I would like to know any historical information, and value, if any.  There appears to be a logo "s (b) t" on the side of it.  Also, am not too sure if it would be considered the top or bottom, but there is an "E" engraved. What would that indicate?  I also have a glass insulator from H and C Co.  Do you have any information on that?  Thank you for you help.

Answer
Hi Ron,

Your porcelain insulator is a relatively modern style for medium voltage distribution.  The logo is S (a B within an O) T --> Which is for Ohio Brass and "Silent Type".  Ohio Brass based out of Mansfield, OH made insulators from the turn of the last Century until the 1970s.  The Silent Type refers to a special conductive glaze used on the dome and pin-hole to reduce AM radio noise.  I'd date this piece from the late 1950's into the 1960's.  I do not know the significance of the "E" but it may have been a tracking mark.  These are pretty common with a $2-$3 trade value.

I suspect your glass insulator may be marked H.G.Co.?  This is for the Hemingray Glass Company -- without a picture I cannot identify further as they made many styles.

         Thanks, --Bob