If the home is a two wire system w/o ground and you install a GFCI recepacle on the first outlet of the circuit, will all outlets down stream also be protected in the same manner as if it was a two wire with ground.
Yes, you know the ground has nothing to do with the measurement and operation of a GFCI receptacle per se…while a ground is important…the level of protection from a GFCI remains the same.
Don’t confuse the ground in a 2 wire cable with the function of a GFCI…totally different things…but long story short…the GFCI will function with or without the ground wire…but you will have to do additional steps…as far as labeling the receptacles and so on.
If you have a NEC handly read Art 406.3(D)(3)…kinda says it all…
An important note here is this…Premission to replace nongrounding type receptacles with GFCI-protected grounding type receptacles does not apply to new receptacle outlets that extend from an existing ungrounded outlet…once you add a receptacle outlet extention the receptacle SHALL BE of the grounding type and it SHALL have its grounding terminal grounded in accordance with Art 250.130©…many find this helpful…when they ask…cant I just tap onto the existing 2 wire circuit…and well it gets all messy like that…
Paul, thanks
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I agree with Paul that the answer is basically … Yes … (in fact a GFCI has better protection).
But one other thing to note is that it must be wired correctly with the downstream receptacles connected to the “Load” side of the GFCI recepacle (and not the “Line” side).
good side note Robert. you gatta remember that if you connect a downstream outlet off a gfci, on the line side then the other outlets are not protected. i use this excact method to connect an overhead light off a gfci without the light going off when the outlet is tripped. and the other way in a kitchen when i want all the following outlet to be protected off the first gfci, i connect every thing downstream to the load side, once you do that off the gfci, then “line” and “load” don’t matter anymore because a regular (non gfci) outlet doesn’t have the option.
Also remember…if you do this you MUST label the receptacles as GFCI Protected and No Ground Present…just a reminder if you are planning on replacing with 3 hole plugs…
Here is a slide from an HI course I teach with a typical GFCI receptacle and the connection terminals
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Ummm…Robert? Maybe you should double check that slide.
Good pickup … new slide I added without checking the notes. Fixed … 
Was the question … Can a GFCI provide downstream protection on a **2 wire **system. Think about it. If a ground is missing between outlets and a grounding type outlet is used (not a 2 prong polarized) the GFCI cannot sense a ground fault from a 3 prong plug/appliance.
We went thru this not long ago on a remodel with the Homeowner balking at the $13 a piece cost for a GFCI at every location in his older home that he wanted the polarized replaced with grounded outlets.
He didn’t believe me and asked the inspector about it. We changed two and I’m sure he just installed the other grounded outlets thru out.
Without a ground, GFCI will not protect downstream ungrounded outlets.
The gfci will trip if it senses a difference in current between the neutral and the hot. The above scenario would cause such a difference, therefore the downstream receptacle would be protected. the lack of a ground wire has no effect on its operation.
if you connect it right, the outlet can’t tell were the fault came from, weather it’s from the gfci, or down stream, or what. in fact the “outlet” usualy never has the fault, usualy it’s the hair dryer, toaster, or what ever is plugged into it. and to say that, i feel i should also state the obviose in that, when you plug in an appliance, it is now “downstream” from the outlet.
