I stumbled (my normal mode of travel)upon the answer to a Q we've had in the past, but never quite solved.
When did the NEC begin to require 15 and 20 amp receptacles to be grounded?
1947 2124(b) Required in Laundry
1950 2124(b) ""
1953 2124(b) ""
1956 2124(b) Added exterior & garage with direct grade access.
1959 210-22(b) Added kitchen sinks, basements, cellars, and workshops
1962 210-22(b) Required on all outlets on 15 & 20 amp circuits.
It found its way to 210-7(a) where it remained until the 2002 Code. It now resides at 406.3(B)
