On November 8, 1904 Harvey Hubbell Jr. patented the first electrical plug, an invention that changed the industry forever. The receptacle was like the base of an Edison base light bulb.

[Linked Image from cthist.chnm.org]

The 2 prong design was prone to shocking users,
so in 1928 Philip Labre invented the 3 prong plug with a safety ground.

Harvey Hubbell III took his father's invention a step further, and in 1938 introduced the first Twist Lock plugs.

Hubbell had previously patented the first pull chain light socket in 1896.



Hubbell was quite the visionary