According to Jay :

Chris Lewis wrote:

According to Jay :

GFI outlets do not work without a proper ground. (The "test" button
trips them, but the plug in tester will not). I know this because I
failed a CO because a GFI was on an ungrounded circuit (knob and tube).

The inspector was either ignorant of the NEC, or, you misunderstood why
you failed inspection.

The NEC (and CEC) _explicitly_ approves GFCIs on ungrounded circuits for
renovation/repair work if you don't have a real ground.

They work just fine without grounds.

OK. Let me correct this. The "tester" failed to trip the GFI. Maybe
it would work if you jammed a fork in the slots or something. I wasn't
about to argue with the Code Inspector for a $10 fix.

If the "tester" the inspector used "tested" the GFI by shunting current
to the ground prong, there's two possibilities:

1) The inspector did not take into account the _clear_ wording
in the NEC that permits three prong GFCIs (without any ground
whatsoever) as a substitute for grounding.
2) He tested another outlet, and faulted you for not having the
sticker.

There's a third possibility: he figured that getting a "real ground" was
sufficiently easy that you _should_ do it anyway. The fact that you could
for $10 means it was worth it.

I suggest you peruse http://www.faqs.org/faqs/electrical-...ection-35.html
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.