406.4(2) Non?Grounding-Type Receptacles. Where attachment
to an equipment grounding conductor does not exist in the
receptacle enclosure, the installation shall comply with
(D)(2)(a), (D)(2)(b), or (D)(2)(c).
(a) A non?grounding-type receptacle(s) shall be permitted
to be replaced with another non?grounding-type receptacle(
s).
(b) A non?grounding-type receptacle(s) shall be permitted
to be replaced with a ground-fault circuit interrupter type
of receptacle(s). These receptacles shall be marked
?No Equipment Ground.? An equipment grounding conductor
shall not be connected from the ground-fault circuit interrupter-
type receptacle to any outlet supplied from the
ground-fault circuit-interrupter receptacle.
(c) A non?grounding-type receptacle(s) shall be permitted
to be replaced with a grounding-type receptacle(s)
where supplied through a ground-fault circuit interrupter.
Grounding-type receptacles supplied through the groundfault
circuit interrupter shall be marked ?GFCI Protected?
and ?No Equipment Ground.? An equipment grounding
conductor shall not be connected between the grounding type
receptacles.