In ,
Nate Nagel typed:
On 06/07/2011 07:07 PM, Ralph Mowery wrote:
"Nate wrote in message
...
Hi all

am looking for a hopefully easy to obtain, not too
expensive method of demonstrating that a receptacle is
GFCI protected... long story short. Am selling house,
got offer. Home inspector came through and wrote up
two receptacles as being "ungrounded" despite them
actually having the blue stickers on them that said
"GFCI Protected - No Equipment Ground" (duh) before you
ask, it would be fairly difficult to pull grounds to
these boxes, otherwise I'd not be fighting. Also there
are a approximately 5 or 6 other receps throughout the
house that I haven't grounded yet that are in a similar
situation, and I don't want to open that can of worms
whereby accepting that the lack of a ground at these
receps is a fault that needs to be corrected leads to
the request to ground *everything.* (house was built
in 1948, before you ask. I did update a good bit of
the wiring already, just not all of it. Everything is
to the best of my knowledge code compliant at this
time, and in fact I got a permit for the rewiring I did
on the 2nd floor a while back.) SO.

I scanned the page of the NEC (2008 edition, which is
what my AHJ is using these days) addressing the
replacement of ungrounded receptacles; called the head
inspector to confirm that there were no local addendums
to the code (he said no) and so I have a case, right? I just need to
demonstrate that the receps are in fact
downstream of a GFCI. Here's where I had a moment of dumbass. I
figured I
would just stop by the Local Hardware Sellin' Emporium
and get one of those plug in cube testers - kind of
like the one I already have but this time the fancy one
with the little button on the top to test a GFCI. That
should do it, right? Well I get it home (not the house
for sale, my current temporary residence) and plug it
in to a kitchen recep, push the button, GFCI pops. Then
I read the instructions - says it may not work on
ungrounded receps. Of course it wouldn't - it probably
just has a resistor that the button inserts between hot
and ground so that it allows a current slightly higher
than 5 mA @ 120V. duh! So the question is - is there a tester
available that I
could use to demonstrate the principle to someone who's
not really clueful about such things that the GFCI
really works? I could use a test lead to connect the
ground pin to a faucet or something, but I have a
feeling that that wouldn't really help the case that I
know what I'm talking about and did a proper job in
front of people who aren't really clueful about
electricity and have never heard of the NEC... any ideas?


The GFCI works by compairing the current on the hot wire
to the neutral wire. If they are not ballanced, it
assumes that current is going to ground somewhere and
opens the circuit. The only way to test it is to create an unbalanced
condition. Many testers put a resistor from the hot
wire to ground. To test the ones without a ground such
as you have, you will need to run a wire from the ground
pin of the socket or tester to a grounded item. Such as
to a grounded receptical or other grounded device. To demonstrate the
recepticals are protected, put a lamp
in them and go to the testor and plug it into the GFCI
that protects them. When you trip that socket, it
should cut off the current to the other ones if the GFCI
socket is grounded.

Right, I just don't know if that constitutes "proof" to
someone who really doesn't know what's going on. I don't
have the couple grand to pay an electrician to "fix" all
this, nor do I have the free time between now and closing
to do it myself.
nate

I think you can argue this one yourself by simply arranging a vist to the
office once you have your head firmly around the requirements of the NEC.
Try googling for "gfci design" WITH THE QUOTES to learn more about how they
work in 2-wire setups.
Then be sure your receptacles/markings are all in place as the NEC requires
for 2 and/or 3 wire receptacles or whatever else might be being protected.
The gfci should also be properly current rated of course.

HTH,

Twayne`