I have an old house with a lot of knob & tube (and some sort of slightly newer but still ungrounded) wiring.
The previous owner replaced most outlets with 3-prong ungrounded. To improve safety I am replacing most of those with no equipment ground GFCI outlets. Which is pretty pricy but less than a house rewire. :)
I know with modern NM grounded wiring you can place a GFCI at the beginning of a circuit which will then provide GFCI protection to all downstream load recepticals. But I am not sure if there is still true if there isn't a common ground connecting all the receptacles?
It would be nice if true, because I can reduce the number of GFCI outlets I use around my house. And not that it matters but I am using these GFCI outlets.
406.4(D)(2)(b), it seems to imply that receptacles will be placed in series on the "load side" of the GFCI, and that will be fine as long as you leave the ground(s) unconnected?