Bathroom GFCI with no ground?
Jay-T
receptacle. There is no ground wire going to the existing receptacle and no
grounded metal cable or grounded metal outlet box -- just two separate
wires, one white and one black. There is also no practical way to run a new
ground wire back to the service.
In this situation, is it okay to go ahead and install the GFCI receptacle
and put the sticker on it that says "No Equipment Ground"?
UP.SO. I "could" run a ground wire from the GFCI receptacle to a cold water
pipe and make sure that there is a jumper across the hot water tank in and
out pipes and across the water meter. But, I think I read somewhere about
that being a bad idea (using the cold water pipe for a ground). That is a
bad idea, right?
Jay-T
DerbyDad03
Yes, it's OK to install a GFCI with no ground and mark it as such.
Since it's OK to install a GFCI with no ground, there's no need to
answer your second question.
UP.SO. BTW...It's a bad idea.
bud--
> I want to replace an existing 2-prong receptacle in a bathroom with a GFCI
> receptacle. There is no ground wire going to the existing receptacle and no
> grounded metal cable or grounded metal outlet box -- just two separate
> wires, one white and one black. There is also no practical way to run a new
> ground wire back to the service.
>
> In this situation, is it okay to go ahead and install the GFCI receptacle
> and put the sticker on it that says "No Equipment Ground"?
Yes
>
> P.S. I "could" run a ground wire from the GFCI receptacle to a cold water
> pipe and make sure that there is a jumper across the hot water tank in and
> out pipes and across the water meter. But, I think I read somewhere about
> that being a bad idea (using the cold water pipe for a ground). That is a
> bad idea, right?
Used to be code compliant up to about 10 years ago. It isn't now since
existing metal in the path back to the system ground can be replaced by
plastic in the future.
--
bud--
terry
Use GFCI because it operates on the 'difference' in current between
live and neutral. If someone did get a contact or drop the hair dryer
in the wet metal bath tub any conseuent current likely to trip the
GFCI safely.
Mark
>
> Use GFCI because it operates on the 'difference' in current between
> live and neutral. If someone did get a contact or drop the hair dryer
> in the wet metal bath tub any conseuent current likely to trip the
-
agreed, but will the TEST button still work without a ground?
Mark
Wayne Whitney
> agreed, but will the TEST button still work without a ground?
Yes, as I understand it (I haven't tried it). I believe the TEST
button in the receptacle allows a small current to pass from the LINE
side hot to the LOAD side hot around the current transformer, thereby
creating the imbalance that should trip the GFCI. In contrast a
plug-in tester will not work, as it relies on the ground connection.
Cheers, Wayne
DerbyDad03
Yes.
The test button does not send any current to ground so no ground is
required for it to work.
Jay-T
>> P.S. I "could" run a ground wire from the GFCI receptacle to a cold
>> water pipe and make sure that there is a jumper across the hot water
>> tank in and out pipes and across the water meter. But, I think I
>> read somewhere about that being a bad idea (using the cold water
>> pipe for a ground). That is a bad idea, right?
>
> Used to be code compliant up to about 10 years ago. It isn't now since
> existing metal in the path back to the system ground can be replaced
> by plastic in the future.
That's interesting. Thanks. I never would have thought of that -- the PEX
or plastic replacement in the future.
Jay-T
Thanks. I wondered about that too.
Looks like I won't have a problem going ahead with the GFCI even though
there is no ground.
DerbyDad03
>
> - Show quoted text -
BTW...not only is it OK to (and you should) replace the ungrounded
bathroom receptacle with a GFCI, it is also code compliant to replace
any 2 prong, ungrounded receptacle with a 3 pronged receptacle as long
as that receptacle is protected by a GFCI and marked as having No
Equipment Ground.
For example, if you have a circuit full of daisy chained 2 pronged,
ungrounded receptacles, replace the first one in the circuit with a
GFCI and wire all the downstream 3 prong, yet still ungrounded
receptacles off of the load side.
It's a fairly common practice and allows for the use of three pronged
cords in "older" homes.
Michael Dobony
And without a ground the GFI may not work properly.
DerbyDad03
> On Wed, 3 Feb 2010 20:35:57 +0000 (UTC), Wayne Whitney wrote:
>
> >> agreed, but will the TEST button still work without a ground?
>
> > Yes, as I understand it (I haven't tried it). I believe the TEST
> > button in the receptacle allows a small current to pass from the LINE
> > side hot to the LOAD side hot around the current transformer, thereby
> > creating the imbalance that should trip the GFCI. In contrast a
> > plug-in tester will not work, as it relies on the ground connection.
>
> > Cheers, Wayne
>
> And without a ground the GFI may not work properly.
Please explain.
Twayne
Michael Dobony <sur...@stopassaultnow.net> typed:
A GFCI will indeed work properly and to specs without a ground. Go read how
they work and why/when they trip. Every box and most sites tell you what to
do when there is no third wire. The OP had it right. Earth is NOT used in
the operation of the GFCI.
http://www.doityourself.com/stry/gfci
http://wiki.answers.com/Q/How_does_the_ground_or_earth_wire_of_an_appliance_protect_a_user_if_there_is_a_fault_with_that_particular_appliance
or if you're Canadian
http://en.wikipedia.org/wiki/Residual-current_device
Google is full of good information
HTH,
Twayne
HTH,
Twayne
--
--
Newsgroups are great places to get assistance.
But always verify important information with
other sources to be certain you have a clear
understanding of it and that it is accurate.
Twayne
DerbyDad03 <teama...@eznet.net> typed:
That's correct. The "ground" in the name is NOT meaning current inside the
device going to ground; it means power finding an improper path to ground,
in general.
Twayne
Jay-T <Jay-T@noelcvm,.lkm> typed:
You will be fine. If in doubt, look it up on Google or better yet, read the
box sides in the store; the information is usually right on the outside of
the containers.
Twayne
DerbyDad03 <teama...@eznet.net> typed:
NO, it does NOT "allow" use of 3-wire equipment!! If a 3-wire piece of
equipment is plugged into an outlet, the earth ground in that case DOES need
to be present. THAT is why the outlets must be labeled as having NO ground!
It's to prevent just that kind of accident waiting to happen.
DerbyDad03
> Innews:f2d75c5a-ff81-4250...@c4g2000yqa.googlegroups.com,
> DerbyDad03 <teamarr...@eznet.net> typed:
Perhaps we need some clarification here.
We are talking about people protection only. We're not discussing
whether the absence of a ground will be a detriment to the operation
of the equipment.
It is my understanding that the GFCI will protect the user should
there be current leakage to ground within the device.
If there is any type of short to ground within the device then there
will be a differential between the current on the hot and the current
on neutral and the GFCI will trip and the user will be protected.
Why else would the NEC allow for the use of a 3 prong outlet on an
ungrounded circuit if they didn't expect you plug a 3 prong cord into
it?
You'll note that code says it must be labeled as No Equipment Ground,
not simply No Ground.
For the safety of us all, I won't mind if you correct me.
do_not_...@my-deja.com
Mark wrote:
>but will the TEST button still work without a ground?
Yes, since the test circuit is internal to the GFCI and includes an
approximately 15,000 ohm resistor that connects between the device's
hot and ground leads when the TEST button is pressed.
GFCIs pass the hot and neutral AC lines through the center of a
transformer coil. Normally the currents in the wires are equal and
opposite, resulting in no current flow in the secondary of this
transformer, but when a ground fault occurs, the wires will not carry
equal current, and that's why GFCI operation does not require a ground
connection. In fact GFCIs are required to provide protection even
without that ground.
do_not_...@my-deja.com
The test button merely connects the hot to the GFCI's ground
reference, so no earth ground is needed to test operation. But a plug-
in GFCI tester will work, whether or not the GFCI is earthed.
Here's National's document for their old LM1851 GFCI chip:
www.national.com/ds/LM/LM1851.pdf
do_not_...@my-deja.com
Michael Dobony wrote:
>And without a ground the GFI may not work properly.
Absolute nonsense, as GFIs measure only the imbalance of currents in
the hot and neutral lines that pass through their current sensing
transformers. No GFI can require an earth ground for proper
operation and still meet UL standards.
bud--
>
> Wayne Whitney wrote:
>> On 2010-02-03, Mark <mako...@yahoo.com> wrote:
>>
>>> agreed, but will the TEST button still work without a ground?
>> Yes, as I understand it (I haven't tried it). I believe the TEST
>> button in the receptacle allows a small current to pass from the LINE
>> side hot to the LOAD side hot around the current transformer, thereby
>> creating the imbalance that should trip the GFCI. In contrast a
>> plug-in tester will not work, as it relies on the ground connection.
Right except it is line side hot to load side neutral (or vice versa).
>
> The test button merely connects the hot to the GFCI's ground
> reference, so no earth ground is needed to test operation.
Nope. The GFCI outlet circuit makes no connection to "ground". The test
button connects a resistor from the hot wire ahead of the current
transformer to the neutral downstream from the current transformer (or
vice versa) resulting in a current through the transformer only on the
neutral wire.
> But a plug-
> in GFCI tester will work, whether or not the GFCI is earthed.
A plug-in tester connects a resistor from hot to ground. Since ground is
not connected to anything a plug-in tester will not work.
>
> Here's National's document for their old LM1851 GFCI chip:
>
> www.national.com/ds/LM/LM1851.pdf
>
Interesting that the circuit (fig 2) does not show the test button that
is on all GFCIs.
Also interesting that the feature that causes an immediate trip if there
is a downstream N-G connection only adds 2 parts.
--
bud--
bud--
> On Feb 3, 8:39 pm, "Twayne" <nob...@spamcop.net> wrote:
>> Innews:f2d75c5a-ff81-4250...@c4g2000yqa.googlegroups.com,
>> DerbyDad03 <teamarr...@eznet.net> typed:
>>
>>
>>
>>> On Feb 3, 4:13 pm, "Jay-T" <Jay-T@noelcvm,.lkm> wrote:
>>>> DerbyDad03 wrote:
>>>>> On Feb 3, 3:29 pm, Mark <makol...@yahoo.com> wrote:
>>>>>>> Use GFCI because it operates on the 'difference' in current
>>>>>>> between live and neutral. If someone did get a contact or drop
>>>>>>> the hair dryer in the wet metal bath tub any conseuent current
>>>>>>> likely to trip the GFCI safely.-
>>>
>>> bathroom receptacle with a GFCI, it is also code compliant to replace
>>> any 2 prong, ungrounded receptacle with a 3 pronged receptacle as long
>>> as that receptacle is protected by a GFCI and marked as having No
>>> Equipment Ground.
Downstream outlets are also tagged "GFCI protected".
Avoid connecting the outlet grounds together on downstream grounded
outlets where a ground is not present.
>>> For example, if you have a circuit full of daisy chained 2 pronged,
>>> ungrounded receptacles, replace the first one in the circuit with a
>>> GFCI and wire all the downstream 3 prong, yet still ungrounded
>>> receptacles off of the load side.
>>> It's a fairly common practice and allows for the use of three pronged
>>> cords in "older" homes.
>> NO, it does NOT "allow" use of 3-wire equipment!! If a 3-wire piece of
>> equipment is plugged into an outlet, the earth ground in that case DOES need
>> to be present. THAT is why the outlets must be labeled as having NO ground!
>> It's to prevent just that kind of accident waiting to happen.
>>
>> HTH,
>>
>> Twayne
>>
> Perhaps we need some clarification here.
>
> We are talking about people protection only. We're not discussing
> whether the absence of a ground will be a detriment to the operation
> of the equipment.
>
> It is my understanding that the GFCI will protect the user should
> there be current leakage to ground within the device.
>
> If there is any type of short to ground within the device then there
> will be a differential between the current on the hot and the current
> on neutral and the GFCI will trip and the user will be protected.
>
> Why else would the NEC allow for the use of a 3 prong outlet on an
> ungrounded circuit if they didn't expect you plug a 3 prong cord into
> it?
Seems like that should have been obvious to Twayne. If 3 wire plugs were
not allowed the NEC would require a 2 wire GFCI outlet - which it
doesn't. The NEC explicitly allows 'grounded outlet' GFCIs on 2 wire
circuits, and as you said above, allows the GFCI to protect conventional
grounded receptacles downstream.
--
bud--
bud--
Its them PEX fanatics on this newsgroup that have ruined it for the rest
of us.
--
bud--
Wayne Whitney
> Why else would the NEC allow for the use of a 3 prong outlet on an
> ungrounded circuit if they didn't expect you plug a 3 prong cord
> into it?
Well, 406.3(B) of the 2008 NEC states: "Receptacles and cord
connectors that have equipment grounding conductor contacts shall have
those contacts connected to an equipment grounding conductor". And
406.3(D), the section that deals with using GFCIs on circuits without
equipment ground, does not appear to override 406.3(B). So I agree
the situation is confusing and the intent is not clear.
Cheers, Wayne
DerbyDad03
Set Lawyer-Speak Mode = True
A 3 prong plug is typically connected to a cord which has an equipment
grounding conductor within, therefore the "cord connector" portion of
406.3(B) is satisfied.
Once this cord is plugged into a 3 prong receptacle, the receptacle's
equipment grounding conductor contact will be connected to the cord's
equipment grounding conductor, this satisfiying the receptacle portion
of 406.3(B). Prior to the insertion of the plug, the grounding hole in
the receptacle is nothing more than an extra hole since it's not
attached to anything. If it's not attached to an equipment grounding
conductor, it isn't a equipment grounding conductor contact because
the code says it isn't.
Set Lawyer-Speak Mode = False
That clears it up, now, doesn't it?
bud--
> On 2010-02-04, DerbyDad03 <teama...@eznet.net> wrote:
>
>> Why else would the NEC allow for the use of a 3 prong outlet on an
>> ungrounded circuit if they didn't expect you plug a 3 prong cord
>> into it?
>
> Well, 406.3(B) of the 2008 NEC states: "Receptacles and cord
> connectors that have equipment grounding conductor contacts shall have
> those contacts connected to an equipment grounding conductor".
406.3-B
"...shall have those contacts connected to an equipment grounding
conductor."
"Exception No. 2: Replacement receptacles as permitted by 406.3-D"
406.3-D
replacement of receptacles shall comply with D-1,2,and 3 as applicable
406.3-D-3
"Non-Grounding Type Receptacles. Where attachment to an equipment
grounding conductor does not exist in the receptacle enclosure, the
installation shall comply with D-3-a, D-3-b, or D-3-c."
406.3-D-3-b allows GFCIs to be used. The GFCI ground terminal is not
allowed to be extended to downstream receptacles
406.3-D-3 allows grounding receptacles to be used where downstream from
a GFCI. A ground is not allowed to be connected between the receptacles.
> And
> 406.3(D), the section that deals with using GFCIs on circuits without
> equipment ground, does not appear to override 406.3(B).
They do not conflict.
> So I agree
> the situation is confusing and the intent is not clear.
The intent is clear. (A rare miss.)
--
bud--
Wayne Whitney
> "Exception No. 2: Replacement receptacles as permitted by 406.3-D"
Whoops, I completely missed that. Thanks for the catch.
Cheers, Wayne
do_not_...@my-deja.com
bud-- wrote:
> do_not_...@my-deja.com wrote:
> >
> > Wayne Whitney wrote:
> >> On 2010-02-03, Mark <mako...@yahoo.com> wrote:
> > The test button merely connects the hot to the GFCI's ground
> > reference, so no earth ground is needed to test operation.
>
> Nope. The GFCI outlet circuit makes no connection to "ground". The test
> button connects a resistor from the hot wire ahead of the current
> transformer to the neutral downstream from the current transformer (or
> vice versa) resulting in a current through the transformer only on the
> neutral wire.
>
> > But a plug-in GFCI tester will work, whether or not the GFCI is earthed.
>
> A plug-in tester connects a resistor from hot to ground. Since ground is
> not connected to anything a plug-in tester will not work.
But I've tried it with a Hubbel (Shock Shield 3-outlet) plug-in GFI
with its ground prong retracted and a Sears branded Leviton wall
outlet GFI connected to the AC through a 2-wire cheater cord. I
believe both used General Instruments GFI chips.
Twayne
DerbyDad03 <teama...@eznet.net> typed:
OK; since we're clarifying, lets be a tad more accuate. I only add this for
clarification, no other reason. Many homes have a mix of such 2 and 3 wire
installations and it's easy to misunderstand some things.
>
> We are talking about people protection only. We're not discussing
> whether the absence of a ground will be a detriment to the operation
> of the equipment.
A GFCI is for "safety", not people. Kind of minor on the surface, but
important in the altogether. Also, lack of a ground for equipment that
needs it -could- lead to lethal shock situations where under a single fault
condition it could lead to anything from shock to fire.
>
> It is my understanding that the GFCI will protect the user should
> there be current leakage to ground within the device.
Well, not from "within the device" but from any point in the entire circuit
on the Load side of the GFCI; wire, connections, equipments, etc..
Sufficient leakage anywhere will trip the GFCI. It simply measures and
compares hot/neutral current, as you said.
>
> If there is any type of short to ground within the device then there
> will be a differential between the current on the hot and the current
> on neutral and the GFCI will trip and the user will be protected.
If there is anything anywhere, not just within the device, that causes a
differential, the gfci will trip.
>
> Why else would the NEC allow for the use of a 3 prong outlet on an
> ungrounded circuit if they didn't expect you plug a 3 prong cord into
> it?
NEC definitely recommends AGAINST doing so, and requires the markings. In
addition, NEC is not the final word; NEC is only minimum requirements. The
local Code Enforcement Office will have the final say on whether a 3-prong
outlet can be used without an earth ground connection. Here such 2-wire
methods with 3-wire outlets etc. are specifically verboten in the kitchen,
bathroom and outbuildings. Many people forget that it's the local codes that
must be satisfied; the NEC may be but one component of the electrical
requirements.
The NEC/local codes would reall only come into the picture if it was new
work. e.g. when I added a ckt, all they checked was the ckt, and nothing in
the rest of the house. Some localities however insist that if you touch the
wiring at all the whole building has to be brought up to code. It varies all
over the map.
>
> You'll note that code says it must be labeled as No Equipment Ground,
> not simply No Ground.
>
> For the safety of us all, I won't mind if you correct me.
Nah, no serious corrections were needed. Just had time to do a little
further clarification, so did.
Regards,
Twayne`
bud--
> In news:6a8edeba-5ad2-441a...@c10g2000vbr.googlegroups.com,
> DerbyDad03 <teama...@eznet.net> typed:
>>
>
> OK; since we're clarifying, lets be a tad more accuate. I only add this
> for clarification, no other reason. Many homes have a mix of such 2 and
> 3 wire installations and it's easy to misunderstand some things.
>
>>
>> We are talking about people protection only. We're not discussing
>> whether the absence of a ground will be a detriment to the operation
>> of the equipment.
>
> A GFCI is for "safety", not people.
Whatever that means.
The 5mA trip level on a GFCI is for people.
Some other GFIs (including most AFCIs) trip on a ground fault of 30mA.
That is for the protection of equipment or fire.
> Kind of minor on the surface, but
> important in the altogether. Also, lack of a ground for equipment that
> needs it -could- lead to lethal shock situations where under a single
> fault condition it could lead to anything from shock to fire.
That, of curse, is what the GFCI is for.
>>
>> It is my understanding that the GFCI will protect the user should
>> there be current leakage to ground within the device.
>
> Well, not from "within the device" but from any point in the entire
> circuit on the Load side of the GFCI; wire, connections, equipments,
> etc.. Sufficient leakage anywhere will trip the GFCI. It simply measures
> and compares hot/neutral current, as you said.
>
>>
>> If there is any type of short to ground within the device then there
>> will be a differential between the current on the hot and the current
>> on neutral and the GFCI will trip and the user will be protected.
>
> If there is anything anywhere, not just within the device, that causes a
> differential, the gfci will trip.
>>
>> Why else would the NEC allow for the use of a 3 prong outlet on an
>> ungrounded circuit if they didn't expect you plug a 3 prong cord into
>> it?
>
> NEC definitely recommends AGAINST doing so,
Cite.
> and requires the markings.
> In addition, NEC is not the final word; NEC is only minimum
> requirements. The local Code Enforcement Office will have the final say
> on whether a 3-prong outlet can be used without an earth ground
> connection. Here such 2-wire methods with 3-wire outlets etc. are
> specifically verboten in the kitchen, bathroom and outbuildings. Many
> people forget that it's the local codes that must be satisfied; the NEC
> may be but one component of the electrical requirements.
> The NEC/local codes would reall only come into the picture if it was
> new work. e.g. when I added a ckt, all they checked was the ckt, and
> nothing in the rest of the house. Some localities however insist that if
> you touch the wiring at all the whole building has to be brought up to
> code.
Where.
There would be no electrical changes in those locations - extremely
counterproductive.
> It varies all over the map.
>
>>
>> You'll note that code says it must be labeled as No Equipment Ground,
>> not simply No Ground.
>>
>> For the safety of us all, I won't mind if you correct me.
>
> Nah, no serious corrections were needed. Just had time to do a little
> further clarification, so did.
You forgot to clarify that your previous post was wrong and Derby was right.
--
bud--