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.
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