Porcelain Suspension Insulators

High Voltage Transmission

Small six inch Jeffery Dewitt suspension insulator with a clevis & pin connection - These smaller suspensions were typically used in pairs on lower voltage distribution circuits.

Early 10 inch Ohio Brass suspension insulator with the Jan. 25, 1910 A.O. Austin patent date.  (Ball and socket connection)

A 10 inch Jeffery Dewitt suspension in the characteristic light blue glaze that they typically used.  Jeffery Dewitt (JD) patented a unique spider-like attach scheme as can be seen in the photo.

A 10 inch Hewlett style suspension insulator.  This design was patented by Edward M. Hewlett on September 15, 1914 and assigned to the General Electric Co.  

Here is a pair of Hewlett insulators with their attaching hardware.  These insulators were very reliable, but were eventually replaced by the cemented cap and pin style due to high cost and complex attachment hardware.

Smaller 7 inch Hewlett made by Locke.

Smallest of the Hewletts at 6 inches..

More modern suspension style -- This 10 inch version was made by Westinghouse and uses a ball and socket connection.

Here is another more recent 10 inch version in a nice shade of gray.  This is made by NGK of Japan.

Here are two heavy duty cobalt blue 10 inch suspension insulators made by NGK of Japan.

Possibly the smallest suspension insulator is this unusual Lapp that is only five inches!  (CD 106 glass insulator for size comparison)