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  #1 (permalink)  
Old 06-24-2007, 12:09 AM
Skeleton Man
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Default proper grounding

Hi guys,

I went ahead and bought a new surge protector as per the lightning
discussion, but it indicates that it's not grounded !

The outlet itself is 3 prong, but the ground wire from the mains is screwed
to the metal box.. there is no ground screw on the outlet itself!

I have never seen an outlet in Canada/USA that has a ground terminal..
everyone always says just connect the ground wire to the box, so I presume
the metal tabs that screw the outlet to its box are supposed to provide the
ground ? (and then from the metal box to ground wire)

If this is correct it seems an awefully risky/stupid system.. I'm from
Australia originally and ALL our outlets use a ground screw.. there are of
course two wire cords for double insultated appliances, but there is NO such
thing as a two prong, non grounded outlet.. (at least not that I have
seen)..

I was thinking maybe it's the whole 120 vs 240v thing, but that would defy
logic because you have twice the current @ 120v..

Chris



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  #2 (permalink)  
Old 06-24-2007, 02:36 AM
kony
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Posts: n/a
Default Re: proper grounding

On Sat, 23 Jun 2007 20:09:03 -0400, "Skeleton Man"
<invalid@guestwho.com> wrote:

>Hi guys,
>
>I went ahead and bought a new surge protector as per the lightning
>discussion, but it indicates that it's not grounded !
>
>The outlet itself is 3 prong, but the ground wire from the mains is screwed
>to the metal box.. there is no ground screw on the outlet itself!
>
>I have never seen an outlet in Canada/USA that has a ground terminal..
>everyone always says just connect the ground wire to the box, so I presume
>the metal tabs that screw the outlet to its box are supposed to provide the
>ground ? (and then from the metal box to ground wire)
>
>If this is correct it seems an awefully risky/stupid system.. I'm from
>Australia originally and ALL our outlets use a ground screw.. there are of
>course two wire cords for double insultated appliances, but there is NO such
>thing as a two prong, non grounded outlet.. (at least not that I have
>seen)..
>
>I was thinking maybe it's the whole 120 vs 240v thing, but that would defy
>logic because you have twice the current @ 120v..
>
>Chris
>



The typical outlet looks like the following and is available
from most hardware stores for about $0.40 each. Ironically
it often costs more per, to buy a 10-pack than individual
outlets.
http://www.levitonproducts.com/catal...0FACB&pid=1208


If your don't have the ground socket, you might consider
replacing them or having someone else do it if you don't
feel qualified.

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  #3 (permalink)  
Old 06-24-2007, 06:27 AM
Skeleton Man
Guest
 
Posts: n/a
Default Re: proper grounding

>The typical outlet looks like the following and is available
>from most hardware stores for about $0.40 each. Ironically
>it often costs more per, to buy a 10-pack than individual
>outlets.
> If your don't have the ground socket, you might consider
>replacing them or having someone else do it if you don't
>feel qualified.


I know what a grounded socket looks like.. I'm guessing the silver screw at
the bottom left is ground ? The sockets I have seen are missing this screw,
but they ARE 3 hole outlets.. (there is a ground socket that accepts a 3
pin plug, but nowhere to attach a ground wire)

Chris



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  #4 (permalink)  
Old 06-24-2007, 06:43 AM
RobertVA
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Posts: n/a
Default Re: proper grounding

Skeleton Man wrote:
> Hi guys,
>
> I went ahead and bought a new surge protector as per the lightning
> discussion, but it indicates that it's not grounded !
>
> The outlet itself is 3 prong, but the ground wire from the mains is screwed
> to the metal box.. there is no ground screw on the outlet itself!
>
> I have never seen an outlet in Canada/USA that has a ground terminal..
> everyone always says just connect the ground wire to the box, so I presume
> the metal tabs that screw the outlet to its box are supposed to provide the
> ground ? (and then from the metal box to ground wire)
>
> If this is correct it seems an awefully risky/stupid system.. I'm from
> Australia originally and ALL our outlets use a ground screw.. there are of
> course two wire cords for double insultated appliances, but there is NO such
> thing as a two prong, non grounded outlet.. (at least not that I have
> seen)..
>
> I was thinking maybe it's the whole 120 vs 240v thing, but that would defy
> logic because you have twice the current @ 120v..
>
> Chris
>


Note that electrical wiring varies in different countries!!!

Some outlet boxes aren't even metal, so they are not necessarily
grounded. There should be a green ground wire as one of the three
conductors in the cable from the distribution box. Someone MAY have
installed an improperly wired three prong outlet were there was
originally a two prong one as a poor substitute for using adapters for
three prong or polarized two prong plugs.

Ground is supposed to have the SAME electrical potential as the neutral.
A connection between either of the hot conductors and neutral provides
120V at 60 Hz. Since the two hot conductors are 1/120 of a second out of
phase, connecting between them (in household applications typically for
an electric range, water heater, clothes dryer or air conditioner/heat
pump) provides 240V (also at 60 Hz).

HIGHLY recommend the use of one of the inexpensive outlet testers
available in many North American home improvement centers to make sure
there are proper grounds in ALL your three prong outlets and to verify
the hot and neutral wires aren't reversed.

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  #5 (permalink)  
Old 06-24-2007, 09:27 AM
Paul
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Posts: n/a
Default Re: proper grounding

Skeleton Man wrote:
>> The typical outlet looks like the following and is available
>>from most hardware stores for about $0.40 each. Ironically
>> it often costs more per, to buy a 10-pack than individual
>> outlets.
>> If your don't have the ground socket, you might consider
>> replacing them or having someone else do it if you don't
>> feel qualified.

>
> I know what a grounded socket looks like.. I'm guessing the silver screw at
> the bottom left is ground ? The sockets I have seen are missing this screw,
> but they ARE 3 hole outlets.. (there is a ground socket that accepts a 3
> pin plug, but nowhere to attach a ground wire)
>
> Chris
>


There is an alternative style here. The brass plate at the
top, implies they are picking up ground from the metal box.
So the metal box would need the green wire connected to it.

http://ec1.images-amazon.com/images/...CL._SS500_.jpg

There are some alternative grounding schemes mentioned here.
Perhaps the code and method has changed over the years. The
introduction of plastic boxes would certainly change the
requirements on the receptacle design. They mention a pigtail
for ground, implying it is the installer's responsibility to
ensure ground is present, when mixing the wrong kind of component
parts.

http://www.ehow.com/how_117546_replace-receptacle.html

Paul

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  #6 (permalink)  
Old 06-24-2007, 05:17 PM
Vanguard
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Posts: n/a
Default Re: proper grounding

"Skeleton Man" <invalid@guestwho.com> wrote in message
news:hP6dnQ_NCKmiKODbnZ2dnUVZ_oavnZ2d@wightman.ca. ..
> Hi guys,
>
> I went ahead and bought a new surge protector as per the lightning
> discussion, but it indicates that it's not grounded !
>
> The outlet itself is 3 prong, but the ground wire from the mains is
> screwed
> to the metal box.. there is no ground screw on the outlet itself!
>
> I have never seen an outlet in Canada/USA that has a ground terminal..
> everyone always says just connect the ground wire to the box, so I
> presume
> the metal tabs that screw the outlet to its box are supposed to
> provide the
> ground ? (and then from the metal box to ground wire)
>
> If this is correct it seems an awefully risky/stupid system.. I'm
> from
> Australia originally and ALL our outlets use a ground screw.. there
> are of
> course two wire cords for double insultated appliances, but there is
> NO such
> thing as a two prong, non grounded outlet.. (at least not that I have
> seen)..
>
> I was thinking maybe it's the whole 120 vs 240v thing, but that would
> defy
> logic because you have twice the current @ 120v..



So when you remove the cover plate and use a flashlight to look at the
cable coming into the box, does it have 2 or 3 wires? If 3 wires, where
do they go? I suppose only 2 of a 3-wire cable may actually enter the
box and the ground is outside the box and attached to the box but that
would only work if the box were metal instead of plastic (so you would
have to unscrew the metal box to look to see if a ground wire went to
it, and hopefully it isn't nailed into a stud).


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  #7 (permalink)  
Old 06-24-2007, 05:57 PM
Jon Danniken
Guest
 
Posts: n/a
Default Re: proper grounding

"Skeleton Man" wrote:
> Hi guys,
>
> I went ahead and bought a new surge protector as per the lightning
> discussion, but it indicates that it's not grounded !
>
> The outlet itself is 3 prong, but the ground wire from the mains is
> screwed
> to the metal box.. there is no ground screw on the outlet itself!


Drill a small hole through the floor and run a copper wire (bare is okay)
over to a metal cold water pipe. Connect the wire to the metal cold water
pipe with the appropriate clamp device (a couple of bucks). Connect the
other end of the copper wire to the ground screw in your outlet, and you now
have a grounded outlet.

Jon



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  #8 (permalink)  
Old 06-24-2007, 07:00 PM
Ken Maltby
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Posts: n/a
Default Re: proper grounding


"Jon Danniken" <jonREMOVETHISdanniken@yahoo.com> wrote in message
news:5e7pj6F352chhU1@mid.individual.net...
> "Skeleton Man" wrote:
>> Hi guys,
>>
>> I went ahead and bought a new surge protector as per the lightning
>> discussion, but it indicates that it's not grounded !
>>
>> The outlet itself is 3 prong, but the ground wire from the mains is
>> screwed
>> to the metal box.. there is no ground screw on the outlet itself!

>
> Drill a small hole through the floor and run a copper wire (bare is okay)
> over to a metal cold water pipe. Connect the wire to the metal cold water
> pipe with the appropriate clamp device (a couple of bucks). Connect the
> other end of the copper wire to the ground screw in your outlet, and you
> now have a grounded outlet.
>
> Jon


****Warning******

That is a very BAD idea, and would violate many building
codes. Your building/home should have a common grounding
point, where the power line enters.

Luck;
Ken



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  #9 (permalink)  
Old 06-24-2007, 09:07 PM
kony
Guest
 
Posts: n/a
Default Re: proper grounding

On Sun, 24 Jun 2007 02:27:59 -0400, "Skeleton Man"
<invalid@guestwho.com> wrote:

>>The typical outlet looks like the following and is available
>>from most hardware stores for about $0.40 each. Ironically
>>it often costs more per, to buy a 10-pack than individual
>>outlets.
>> If your don't have the ground socket, you might consider
>>replacing them or having someone else do it if you don't
>>feel qualified.

>
>I know what a grounded socket looks like..


Then I don't understand what you meant when you wrote:


>I have never seen an outlet in Canada/USA that has a ground terminal..



>everyone always says just connect the ground wire to the box, so I presume
>the metal tabs that screw the outlet to its box are supposed to provide the
>ground ? (and then from the metal box to ground wire)


It could, but the ground wire to the outlet is better. Over
time an outlet might work itself loose from the box, and
this outlet frame-screw-box-ground wire is bound to be
higher impedance (though not a lot in ideal situations).

>I'm guessing the silver screw at
>the bottom left is ground ?


Yes


>The sockets I have seen are missing this screw,
>but they ARE 3 hole outlets.. (there is a ground socket that accepts a 3
>pin plug, but nowhere to attach a ground wire)


Take a closer look at why it's not making electrical
connection to ground. Plug a lamp in to confirm power state
and flip the breaker/pull the fuse, take a multimeter and
check continuity/resistance... or just buy the $0.40 outlet
and install it.


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  #10 (permalink)  
Old 06-24-2007, 09:29 PM
GlowingBlueMist
Guest
 
Posts: n/a
Default Re: proper grounding

"Ken Maltby" <kmaltby@sbcglobal.net> wrote in message
news:DeKdnRYyPvzdIuPbnZ2dnUVZ_g6dnZ2d@giganews.com ...
>
> "Jon Danniken" <jonREMOVETHISdanniken@yahoo.com> wrote in message
> news:5e7pj6F352chhU1@mid.individual.net...
>> "Skeleton Man" wrote:
>>> Hi guys,
>>>
>>> I went ahead and bought a new surge protector as per the lightning
>>> discussion, but it indicates that it's not grounded !
>>>
>>> The outlet itself is 3 prong, but the ground wire from the mains is
>>> screwed
>>> to the metal box.. there is no ground screw on the outlet itself!

>>
>> Drill a small hole through the floor and run a copper wire (bare is okay)
>> over to a metal cold water pipe. Connect the wire to the metal cold
>> water pipe with the appropriate clamp device (a couple of bucks).
>> Connect the other end of the copper wire to the ground screw in your
>> outlet, and you now have a grounded outlet.
>>
>> Jon

>
> ****Warning******
>
> That is a very BAD idea, and would violate many building
> codes. Your building/home should have a common grounding
> point, where the power line enters.
>
> Luck;
> Ken

True Ken,
I was almost killed when I grabbed an outside faucet to wash my hands after
installing carpet at a new house due to an electrician improperly using the
house water pipes as a ground.

The electrician had failed to keep up with the local building code changes.
Seems that a year or so the city in that area had switched to using a
plastic water line from the water main to two feet inside the basement, then
attached a water meter. From there the plumber had used copper water pipes
for the rest of the installation. A ground rod had not been installed by
the electrician outside the building and connected to both the ground lug
inside the circuit breaker box and the water pipes as per the "revised"
local building code.

At my request a city building inspector came out to the house to verify my
complaint about what had happened. This resulted in the building being
condemned and had the electrical meter removed pending the repair of the
wiring. They cancelled the license of the electrician who did the
installation and levied a six figure fine against electrician and the
company he worked for.

Every installation by that company going back three years were then
re-inspected by the city looking for similar problems.



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  #11 (permalink)  
Old 06-24-2007, 11:00 PM
Skeleton Man
Guest
 
Posts: n/a
Default Re: proper grounding

>There is an alternative style here. The brass plate at the
>top, implies they are picking up ground from the metal box.
>So the metal box would need the green wire connected to it.


>http://ec1.images-amazon.com/images/...CL._SS500_.jpg


That's exactly what I was talking about! (I thought I was going nuts when I
didn't see a ground screw on my outlets!!)

Not sure about the brass but it has metal tabs like that and the ground wire
attaches to the metal box. All the outlets here are wired like that, but my
surge protector tells me there's no ground connection.. (the ground wire is
definately attached to the box, and I followed the wiring all the way to the
breaker panel)

I don't have anything attached to ground that I could run an external ground
wire too either.. it would mean adding an extra wire all the way from the
outlet down into the basement onto a water pipe or something..

Chris



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  #12 (permalink)  
Old 06-24-2007, 11:01 PM
Skeleton Man
Guest
 
Posts: n/a
Default Re: proper grounding

>>I know what a grounded socket looks like..
>Then I don't understand what you meant when you wrote:
>>I have never seen an outlet in Canada/USA that has a ground terminal..


See Paul's post.. the style of outlet in the photo he posted is the same as
what I have.. no ground screw..

Chris




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  #13 (permalink)  
Old 06-24-2007, 11:11 PM
Skeleton Man
Guest
 
Posts: n/a
Default Re: proper grounding

I never thought, if I can get the style of outlet that kony posted, that
should solve my problem.. assuming the ground wire is ok..

All I should need to do is test for continuity from neutral to ground right
? (the two are tied together at the panel right?)

Stupid question here, but.. if neutral is wired to ground as a return path
for electricity, if you removed the ground wire from the fixture (so it's
only path to ground was through you) and held it, would you get zapped ?
(obviously while it has a quicker path to ground, it's not going to take the
more resistive path through you)

Chris



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  #14 (permalink)  
Old 06-25-2007, 01:24 AM
Skeleton Man
Guest
 
Posts: n/a
Default Re: proper grounding

>I was almost killed when I grabbed an outside faucet to wash my hands after
>installing carpet at a new house due to an electrician improperly using the
>house water pipes as a ground.
>The electrician had failed to keep up with the local building code changes.


>Seems that a year or so the city in that area had switched to using a
>plastic water line from the water main to two feet inside the basement,

then
>attached a water meter. From there the plumber had used copper water pipes
>for the rest of the installation.


If I understand right, the common ground for the mains (joined to neutral)
was connected to a section of the copper pipes, but because of the plastic
section the water pipe was not grounded at all ? (hence 120V running through
all your faucets).

Chris



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  #15 (permalink)  
Old 06-25-2007, 03:09 AM
Paul
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Posts: n/a
Default Re: proper grounding

Skeleton Man wrote:
> I never thought, if I can get the style of outlet that kony posted, that
> should solve my problem.. assuming the ground wire is ok..
>
> All I should need to do is test for continuity from neutral to ground right
> ? (the two are tied together at the panel right?)
>
> Stupid question here, but.. if neutral is wired to ground as a return path
> for electricity, if you removed the ground wire from the fixture (so it's
> only path to ground was through you) and held it, would you get zapped ?
> (obviously while it has a quicker path to ground, it's not going to take the
> more resistive path through you)
>
> Chris
>
>


There is a justification for the safety ground here.

http://www.epanorama.net/documents/g..._separate.html

I checked downstairs, and I cannot see how my panel is grounded.

I checked my water meter, and it has a substantial jumper wire and
clamps, on either side of the meter. Implying some code at some point
in time, wanted the cold water to have continuity to the street side.

But I cannot say exactly what my house wiring is relying on for safety
ground. I don't see anything big and obvious entering the panel.

The mast on the side of the house, has the usual three wires, but those
would be the two phases (115/115) and neutral.

The safety ground is engaged in two situations.

1) An equipment fault, causes live to contact the chassis of the
equipment. For example, the casing of your ATX PSU is probably
connected to safety ground. The metal chassis of the computer
comes in contact with it. If a live conductor were to touch the
chassis, it would be shunted to safety ground.

2) Switching power supplies use a little trick. They have EMI
filtering on the A.C. input side. The following device contains
the equivalent circuitry to the EMI filter function. The trick
is the two caps joined to "ground", which in this case the ground
is the safety ground. The caps divert high frequency noise (say
up to 30MHz or more) from the switching harmonics, to ground. But
the 120VAC also ends up being shunted as well. You can see in this
spec, that the "leakage" current is known and is not an accident,
and a device using this circuit is expected to have a proper safety
ground, to eat the 1.2 milliamps listed here.

http://www.cor.com/PDF/N.pdf

The leakage is enough, that if a three prong computer is plugged
into an improperly "safety grounded" outlet, the chassis of the
computer is raised above ground and is "hot". Each time the user
touches the chassis, and also touches something which is properly
grounded, they'll get a shock. There are occasional posters to
the newsgroups who suffer one of these shocks, and they don't
realize that their safety ground is not properly implemented
or is defective.

So if using a computer in a domestic situation, that is one reason
I'd want to verify that the safety ground is working.

Paul

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  #16 (permalink)  
Old 06-25-2007, 03:21 AM
Jon Danniken
Guest
 
Posts: n/a
Default Re: proper grounding

"Ken Maltby" wrote:
> "Jon Danniken" wrote:
>>
>> Drill a small hole through the floor and run a copper wire (bare is okay)
>> over to a metal cold water pipe. Connect the wire to the metal cold
>> water pipe with the appropriate clamp device (a couple of bucks).
>> Connect the other end of the copper wire to the ground screw in your
>> outlet, and you now have a grounded outlet.
>>
>> Jon

>
> ****Warning******
>
> That is a very BAD idea, and would violate many building
> codes. Your building/home should have a common grounding
> point, where the power line enters.


Yes, it should, but older homes don't have grounded outlets. For such
houses, there is nothing wrong with grounding to a metal water pipe, that's
why they sell the damn clamps in the first place, duh.

Oh yeah, this only works when the metal pipe goes through the ground,
another duh.

Seriously, given the choice between no grounded outlet and an outlet
grounded to a water pipe, you just ground the outlet to a water pipe. It's
been done hundreds of thousands of times, and it works fine if you use some
common sense.

Jon



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  #17 (permalink)  
Old 06-25-2007, 03:25 AM
GlowingBlueMist
Guest
 
Posts: n/a
Default Re: proper grounding

"Skeleton Man" <invalid@guestwho.com> wrote in message
news:uLadnUzDo6jHheLbnZ2dnUVZ_oqmnZ2d@wightman.ca. ..
> >I was almost killed when I grabbed an outside faucet to wash my hands
> >after
>>installing carpet at a new house due to an electrician improperly using
>>the
>>house water pipes as a ground.
>>The electrician had failed to keep up with the local building code
>>changes.

>
>>Seems that a year or so the city in that area had switched to using a
>>plastic water line from the water main to two feet inside the basement,

> then
>>attached a water meter. From there the plumber had used copper water
>>pipes
>>for the rest of the installation.

>
> If I understand right, the common ground for the mains (joined to neutral)
> was connected to a section of the copper pipes, but because of the plastic
> section the water pipe was not grounded at all ? (hence 120V running
> through
> all your faucets).
>
> Chris
>

Sounds right to me.
Due to PVC (plastic) drain pipes in use the cast iron and stainless steel
fixtures and fittings were live as well because of the attached faucets.



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  #18 (permalink)  
Old 06-25-2007, 06:32 PM
Ken Maltby
Guest
 
Posts: n/a
Default Re: proper grounding


"Jon Danniken" <jonREMOVETHISdanniken@yahoo.com> wrote in message
news:5e8qkaF374msaU1@mid.individual.net...
> "Ken Maltby" wrote:
>> "Jon Danniken" wrote:
>>>
>>> Drill a small hole through the floor and run a copper wire (bare is
>>> okay) over to a metal cold water pipe. Connect the wire to the metal
>>> cold water pipe with the appropriate clamp device (a couple of bucks).
>>> Connect the other end of the copper wire to the ground screw in your
>>> outlet, and you now have a grounded outlet.
>>>
>>> Jon

>>
>> ****Warning******
>>
>> That is a very BAD idea, and would violate many building
>> codes. Your building/home should have a common grounding
>> point, where the power line enters.

>
> Yes, it should, but older homes don't have grounded outlets. For such
> houses, there is nothing wrong with grounding to a metal water pipe,
> that's why they sell the damn clamps in the first place, duh.
>
> Oh yeah, this only works when the metal pipe goes through the ground,
> another duh.
>
> Seriously, given the choice between no grounded outlet and an outlet
> grounded to a water pipe, you just ground the outlet to a water pipe.
> It's been done hundreds of thousands of times, and it works fine if you
> use some common sense.
>
> Jon


It would be a mistake to assume that all the readers of a post
will be exercising "common sense", and when dealing with mains
voltage, it's best not to assume at all.

Using separate grounds for signal equip. can work, (as long as
there is no interconnection). But when it comes to power circuits
you are risking creating a dangerous (to the equipment if not to
anyone who comes into contact) difference in ground potential.

Connecting all the grounds together, is one way to address these
issues, but it needs to be engineered into the building.

Luck;
Ken

P.S. "Older homes" are more likely to have buried metal water
supply pipes. There is the consideration though that many
"older homes" have, at some point, been "brought up to code"
and in the process had some plastic isolation from the water
main applied. If done properly,a grounding point would have
been properly established.



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  #19 (permalink)  
Old 06-25-2007, 07:04 PM
Ken Maltby
Guest
 
Posts: n/a
Default Re: proper grounding


"Ken Maltby" <kmaltby@sbcglobal.net> wrote in message
news:e-KdnUo0OJyklx3bnZ2dnUVZ_gudnZ2d@giganews.com...
>
> "Jon Danniken" <jonREMOVETHISdanniken@yahoo.com> wrote in message
> news:5e8qkaF374msaU1@mid.individual.net...
>> "Ken Maltby" wrote:
>>> "Jon Danniken" wrote:
>>>>
>>>> Drill a small hole through the floor and run a copper wire (bare is
>>>> okay) over to a metal cold water pipe. Connect the wire to the metal
>>>> cold water pipe with the appropriate clamp device (a couple of bucks).
>>>> Connect the other end of the copper wire to the ground screw in your
>>>> outlet, and you now have a grounded outlet.
>>>>
>>>> Jon
>>>
>>> ****Warning******
>>>
>>> That is a very BAD idea, and would violate many building
>>> codes. Your building/home should have a common grounding
>>> point, where the power line enters.

>>
>> Yes, it should, but older homes don't have grounded outlets. For such
>> houses, there is nothing wrong with grounding to a metal water pipe,
>> that's why they sell the damn clamps in the first place, duh.
>>
>> Oh yeah, this only works when the metal pipe goes through the ground,
>> another duh.
>>
>> Seriously, given the choice between no grounded outlet and an outlet
>> grounded to a water pipe, you just ground the outlet to a water pipe.
>> It's been done hundreds of thousands of times, and it works fine if you
>> use some common sense.
>>
>> Jon

>
> It would be a mistake to assume that all the readers of a post
> will be exercising "common sense", and when dealing with mains
> voltage, it's best not to assume at all.
>
> Using separate grounds for signal equip. can work, (as long as
> there is no interconnection). But when it comes to power circuits
> you are risking creating a dangerous (to the equipment if not to
> anyone who comes into contact) difference in ground potential.
>
> Connecting all the grounds together, is one way to address these
> issues, but it needs to be engineered into the building.
>
> Luck;
> Ken
>
> P.S. "Older homes" are more likely to have buried metal water
> supply pipes. There is the consideration though that many
> "older homes" have, at some point, been "brought up to code"
> and in the process had some plastic isolation from the water
> main applied. If done properly,a grounding point would have
> been properly established.


I should add that you can add an equipment grounded outlet
to an existing ungrounded (two wire) circuit by connecting the
grounded outlet's ground to a grounded cold water pipe, but
the pipe needs to be tied into the building's grounding system.
(In many "older homes" that will be the case.)



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  #20 (permalink)  
Old 06-25-2007, 07:40 PM
w_tom
Guest
 
Posts: n/a
Default Re: proper grounding

On Jun 24, 11:21 pm, "Jon Danniken" <jonREMOVETHISdanni...@yahoo.com>
wrote:
On Jun 24, 11:21 pm, "Jon Danniken" <jonREMOVETHISdanni...@yahoo.com>
wrote:
> Seriously, given the choice between no grounded outlet and an outlet
> grounded to a water pipe, you just ground the outlet to a water pipe. It's
> been done hundreds of thousands of times, and it works fine if you use some
> common sense.


Given a choice between no grounded outlet and an outlet grounded to
water pipe, you either accept the ungrounded outlet as is, run a new
three wire romex from breaker box to outlet, or install a GFCI.
Recommending grounding to any water pipe is completely and totally
dangerous. Jon Danniken should know better - this tone because what
he proposes is not just wrong; it is also dangerous and not
acceptable.

Any electrical connection to any water pipe anywhere must be only to
remove electricity from that pipe. At no time is an grounding
connection made to a pipe to ground electricity. Safety ground wires
to pipes are to remove electricity from that pipe so that electricity
does not find earth ground via a human. No way around that reality.
Provided are three possible solutions. None ground to a water pipe
since that is nothing but dangerous, unacceptable, and recommended by
many who never grasped the bigger picture.


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  #21 (permalink)  
Old 06-25-2007, 07:45 PM
Ken Maltby
Guest
 
Posts: n/a
Default Re: proper grounding


"Paul" <nospam@needed.com> wrote in message news:f5nbk1$cpp$1@aioe.org...
> Skeleton Man wrote:
>> I never thought, if I can get the style of outlet that kony posted, that
>> should solve my problem.. assuming the ground wire is ok..
>>
>> All I should need to do is test for continuity from neutral to ground
>> right
>> ? (the two are tied together at the panel right?)
>>
>> Stupid question here, but.. if neutral is wired to ground as a return
>> path
>> for electricity, if you removed the ground wire from the fixture (so
>> it's
>> only path to ground was through you) and held it, would you get zapped ?
>> (obviously while it has a quicker path to ground, it's not going to take
>> the
>> more resistive path through you)
>>
>> Chris
>>
>>

>
> There is a justification for the safety ground here.
>
> http://www.epanorama.net/documents/g..._separate.html
>
> I checked downstairs, and I cannot see how my panel is grounded.
>
> I checked my water meter, and it has a substantial jumper wire and
> clamps, on either side of the meter. Implying some code at some point
> in time, wanted the cold water to have continuity to the street side.
>
> But I cannot say exactly what my house wiring is relying on for safety
> ground. I don't see anything big and obvious entering the panel.
>
> The mast on the side of the house, has the usual three wires, but those
> would be the two phases (115/115) and neutral.
>
> The safety ground is engaged in two situations.
>
> 1) An equipment fault, causes live to contact the chassis of the
> equipment. For example, the casing of your ATX PSU is probably
> connected to safety ground. The metal chassis of the computer
> comes in contact with it. If a live conductor were to touch the
> chassis, it would be shunted to safety ground.
>
> 2) Switching power supplies use a little trick. They have EMI
> filtering on the A.C. input side. The following device contains
> the equivalent circuitry to the EMI filter function. The trick
> is the two caps joined to "ground", which in this case the ground
> is the safety ground. The caps divert high frequency noise (say
> up to 30MHz or more) from the switching harmonics, to ground. But
> the 120VAC also ends up being shunted as well. You can see in this
> spec, that the "leakage" current is known and is not an accident,
> and a device using this circuit is expected to have a proper safety
> ground, to eat the 1.2 milliamps listed here.
>
> http://www.cor.com/PDF/N.pdf
>
> The leakage is enough, that if a three prong computer is plugged
> into an improperly "safety grounded" outlet, the chassis of the
> computer is raised above ground and is "hot". Each time the user
> touches the chassis, and also touches something which is properly
> grounded, they'll get a shock. There are occasional posters to
> the newsgroups who suffer one of these shocks, and they don't
> realize that their safety ground is not properly implemented
> or is defective.
>
> So if using a computer in a domestic situation, that is one reason
> I'd want to verify that the safety ground is working.
>
> Paul


Your Service Panel will have a grounded conductor terminal bar.
(Grounding Bus) One of the leads running from that will go to an
approved Grounding Electrode and to a connection on the water
pipe within 5' of its entering the building. There is also a Bonding
Jumper required around the water meter, if the grounding electrode
conductor is on the street side of the meter.

There are a number of accepted grounding electrodes/systems,
ranging from an 8' grounding rod to a complete counterpoise.
A "Ufer" ground, is a connection to 20' of reinforcing rod or
bare wire, buried in the foundation. You will defiantly have
a lead from the ground bus inside your service panel to an
approved grounding electrode.

Luck;
Ken



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  #22 (permalink)  
Old 06-25-2007, 07:48 PM
w_tom
Guest
 
Posts: n/a
Default Re: proper grounding

On Jun 25, 3:04 pm, "Ken Maltby" <kmal...@sbcglobal.net> wrote:
> I should add that you can add an equipment grounded outlet
> to an existing ungrounded (two wire) circuit by connecting the
> grounded outlet's ground to a grounded cold water pipe, but
> the pipe needs to be tied into the building's grounding system.
> (In many "older homes" that will be the case


Many assume electricity is same at both ends of a wire. If true,
then safety ground can be tied to white neutral wire. Reality is that
electricity is not same at both ends of a wire. Safety ground
(equipment ground) must connect directly back to the single point
safety ground - that bus bar in the mains box.

Connecting an outlet's safety ground pin to a water pipe is more
than a code violation. It can even mean that insurance has been
invalidated. Receptacle safety ground pin must connect to mains
breaker box ground bus bar.

Why is that ground wire still required to water pipe? All
connections to water pipes remove electricity from that pipe - for
human safety. The intent of the code is obvious. All grounding must
be by conductors dedicated only to grounding functions. Grounding via
items not defined for the purpose is a code violation and a threat to
human safety.

Either a three wire (grounded) cable must connect outlet to breaker
box, or outlet must be only a two prong type, or a GFCI must be
installed. Those are the options. Grounding electricity to any water
pipe is no longer acceptable and is a threat to human life.


Reply With Quote
  #23 (permalink)  
Old 06-26-2007, 02:31 AM
Ken Maltby
Guest
 
Posts: n/a
Default Re: proper grounding


"w_tom" <w_tom1@usa.net> wrote in message
news:1182800458.880118.288520@k79g2000hse.googlegr oups.com...
> On Jun 24, 11:21 pm, "Jon Danniken" <jonREMOVETHISdanni...@yahoo.com>
> wrote:
> On Jun 24, 11:21 pm, "Jon Danniken" <jonREMOVETHISdanni...@yahoo.com>
> wrote:
>> Seriously, given the choice between no grounded outlet and an outlet
>> grounded to a water pipe, you just ground the outlet to a water pipe.
>> It's
>> been done hundreds of thousands of times, and it works fine if you use
>> some
>> common sense.

>
> Given a choice between no grounded outlet and an outlet grounded to
> water pipe, you either accept the ungrounded outlet as is, run a new
> three wire romex from breaker box to outlet, or install a GFCI.
> Recommending grounding to any water pipe is completely and totally
> dangerous. Jon Danniken should know better - this tone because what
> he proposes is not just wrong; it is also dangerous and not
> acceptable.
>
> Any electrical connection to any water pipe anywhere must be only to
> remove electricity from that pipe. At no time is an grounding
> connection made to a pipe to ground electricity. Safety ground wires
> to pipes are to remove electricity from that pipe so that electricity
> does not find earth ground via a human. No way around that reality.
> Provided are three possible solutions. None ground to a water pipe
> since that is nothing but dangerous, unacceptable, and recommended by
> many who never grasped the bigger picture.
>



Not according to DeWalt or the NEC (National Electrical Code)
article 250. A cold water supply line can be an approved grounding
electrode. There are certain requirements for the supply line and it
must include at least a 20' buried run starting within 5' of where it
enters the building. The grounding electrode connector must connect
to the water supply line within 5' of its entering the building, and the
water meter must be bridged bonding both pipes (that entering the
meter and that leaving the meter).

An Equipment ground (that third grounded hole in a modern
outlet) can be made to a cold water pipe as long as the pipe
is bonded to the grounding electrode. If the water supply line
is the grounding electrode and there is no isolation applied to
the intervening pipe, (as would most often be the case in old
homes still wired with two hole outlets) then it is considered
bonded to the grounding electrode.

The equipment ground (the solid copper wire in the Romex)
returns directly to the Ground Bus at the Service Panel, in the
most common setups; this would need to be maintained when
adding to an existing equipment ground circuit. Where there is
no existing equipment ground circuit you can use the grounded
cold water piping to establish one for a run of outlets.

The real problems come if it is not done properly and/or there
are more than the one Equipment grounding circuits established.
(It's still possible to have several separate Equipment grounding
circuits, but they must be properly connected and in isolation
from each other otherwise.)

Just telling people they can connect the ground lead to a
water pipe, is dangerously misleading, without knowing the
precise conditions. If the home is old enough and not been
renovated and only has ungrounded two hole outlets and all
reasonable precautions are taken, it can be done without
causing any problems. But to be safe and legal you would
still need a certified electrician to bless it.

Luck;
Ken



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  #24 (permalink)  
Old 06-26-2007, 05:51 AM
w_tom
Guest
 
Posts: n/a
Default Re: proper grounding

On Jun 25, 10:31 pm, "Ken Maltby" <kmal...@sbcglobal.net> wrote:
> Not according to DeWalt or the NEC (National Electrical Code)
> article 250. A cold water supply line can be an approved grounding
> electrode. There are certain requirements for the supply line and it
> must include at least a 20' buried run starting within 5' of where it
> enters the building. The grounding electrode connector must connect
> to the water supply line within 5' of its entering the building, and the
> water meter must be bridged bonding both pipes (that entering the
> meter and that leaving the meter).
>
> An Equipment ground (that third grounded hole in a modern
> outlet) can be made to a cold water pipe as long as the pipe
> is bonded to the grounding electrode.


You have confused an earthing electrode - a completely different
ground - from equipment 'safety' ground. All outlets must be bonded
to a common point safety ground in the main breaker box. Only main
breaker box makes a connection to earthing - a completely different
ground. Equipment grounds remove electricity from equipment and pipes
to trip circuit breakers (and other functions). Equipment grounds all
meet inside the breaker box.

Does not matter that water pipe is 20 feet in earth. Earthing is a
completely different ground from equipment (safety) ground.
Electricty is different at both ends of a wire. Any connection from
wall receptacles to earth ground must be via that common point bus bar
ground inside main disconnect breaker box. This being only the first
reason why receptacles are never bonded to a water pipe.

If what you have posted is acceptable, then also acceptable is to
drive a ground rod outside the window and ground a receptacle to that
ground rod. That grounding also is not code acceptable. Safety
(equipment) ground and earth ground are two completely different
grounds.

Third, bonding a water pipe to breaker box serves a critical human
safety function. If dangerous electrical currents exist due 'fault'
into a pipe, then the bare copper wire that connects water pipe to
that breaker box bus bar will also protect humans - also connect fault
currents to the common safety ground bus bar. Its purpose is to remove
dangerous voltages from pipes. If that voltage is created by a fault
current is dumped into pipes by another wire, then that wiring fault
must be corrected / removed / disconnected. That latter wire
violates code and may even result in loss of insurance coverage. All
connections to water pipes - including the bypass around meter and
bypass around water heater - are part of a system (newer requirements)
only to *remove* electricity from pipes. Never dump a fault current
into pipes. That means never connect a receptacle ground or electrical
appliance ground to pipes. Never. And yes, that is a change from
code so many generations ago.

Fourth, no matter what pipe a plumber disconnects, disconnected pipe
must never compromise any safetyl grounds. If any safety ground is
dependent on a pipe, then a code violation exists. Whereas that
requirement did not exist generations ago, it does exist today.

You have confused two completely different grounds; have assumed
that electricity at both ends of a wire is same; have assumed safety
(equipment) ground is same as the earthing electrode. All safety
grounds meet at a common point - the main disconnect breaker box. An
earthing electrode connection is made only via that same box. A
receptacle connected to breaker box via cold water pipe violates a
common point ground principle, violates code, and even puts a
plumber's life at risk. All wires to pipes are to remove electricity
so that even a plumber is safe. If a plumber can do anything to pipes
that compromises any safety ground, then wiring is defective. It is
that simple. Never connect a wall receptacle ground to pipes.


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  #25 (permalink)  
Old 06-26-2007, 01:55 PM
Ken Maltby
Guest
 
Posts: n/a
Default Re: proper grounding


"w_tom" <w_tom1@usa.net> wrote in message
news:1182837100.263681.150350@p77g2000hsh.googlegr oups.com...
> On Jun 25, 10:31 pm, "Ken Maltby" <kmal...@sbcglobal.net> wrote:
>> Not according to DeWalt or the NEC (National Electrical Code)
>> article 250. A cold water supply line can be an approved grounding
>> electrode. There are certain requirements for the supply line and it
>> must include at least a 20' buried run starting within 5' of where it
>> enters the building. The grounding electrode connector must connect
>> to the water supply line within 5' of its entering the building, and the
>> water meter must be bridged bonding both pipes (that entering the
>> meter and that leaving the meter).
>>
>> An Equipment ground (that third grounded hole in a modern
>> outlet) can be made to a cold water pipe as long as the pipe
>> is bonded to the grounding electrode.

>
> You have confused an earthing electrode - a completely different
> ground - from equipment 'safety' ground. All outlets must be bonded
> to a common point safety ground in the main breaker box. Only main
> breaker box makes a connection to earthing - a completely different
> ground. Equipment grounds remove electricity from equipment and pipes
> to trip circuit breakers (and other functions). Equipment grounds all
> meet inside the breaker box.
>
> Does not matter that water pipe is 20 feet in earth. Earthing is a
> completely different ground from equipment (safety) ground.
> Electricty is different at both ends of a wire. Any connection from
> wall receptacles to earth ground must be via that common point bus bar
> ground inside main disconnect breaker box. This being only the first
> reason why receptacles are never bonded to a water pipe.
>
> If what you have posted is acceptable, then also acceptable is to
> drive a ground rod outside the window and ground a receptacle to that
> ground rod. That grounding also is not code acceptable. Safety
> (equipment) ground and earth ground are two completely different
> grounds.
>
> Third, bonding a water pipe to breaker box serves a critical human
> safety function. If dangerous electrical currents exist due 'fault'
> into a pipe, then the bare copper wire that connects water pipe to
> that breaker box bus bar will also protect humans - also connect fault
> currents to the common safety ground bus bar. Its purpose is to remove
> dangerous voltages from pipes. If that voltage is created by a fault
> current is dumped into pipes by another wire, then that wiring fault
> must be corrected / removed / disconnected. That latter wire
> violates code and may even result in loss of insurance coverage. All
> connections to water pipes - including the bypass around meter and
> bypass around water heater - are part of a system (newer requirements)
> only to *remove* electricity from pipes. Never dump a fault current
> into pipes. That means never connect a receptacle ground or electrical
> appliance ground to pipes. Never. And yes, that is a change from
> code so many generations ago.
>
> Fourth, no matter what pipe a plumber disconnects, disconnected pipe
> must never compromise any safetyl grounds. If any safety ground is
> dependent on a pipe, then a code violation exists. Whereas that
> requirement did not exist generations ago, it does exist today.
>
> You have confused two completely different grounds; have assumed
> that electricity at both ends of a wire is same; have assumed safety
> (equipment) ground is same as the earthing electrode. All safety
> grounds meet at a common point - the main disconnect breaker box. An
> earthing electrode connection is made only via that same box. A
> receptacle connected to breaker box via cold water pipe violates a
> common point ground principle, violates code, and even puts a
> plumber's life at risk. All wires to pipes are to remove electricity
> so that even a plumber is safe. If a plumber can do anything to pipes
> that compromises any safety ground, then wiring is defective. It is
> that simple. Never connect a wall receptacle ground to pipes.
>


I see you are still full of it. See the NEC Section 250.81 or the
2005 DeWALT Electrical Licensing Guide.

I haven't confused or assumed anything and you can't restate the
situation from what I described in my post, to try and create a
faulty situation. We were describing where there was no existing
equipment/safety ground, a two wire ungrounded residential circuit,
and adding a grounded outlet. The receptacle is connected to the
existing breaker/fuse box via an extension of the existing two wire
circuit. The equipment/safety ground for the new added grounded
three hole outlet/receptacle can connect to a grounded cold water
pipe. The Ground-Fault Current path is through the Neutral, not
through the Equipment/safety lead/wire. Your idea of "removing"
electricity, would be laughable, if it didn't point out how misguided
you are.

Ken
---------------




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  #26 (permalink)  
Old 06-26-2007, 03:44 PM
Bud--
Guest
 
Posts: n/a
Default Re: proper grounding

w_tom wrote:
> On Jun 25, 10:31 pm, "Ken Maltby" <kmal...@sbcglobal.net> wrote:
>> Not according to DeWalt or the NEC (National Electrical Code)
>> article 250. A cold water supply line can be an approved grounding
>> electrode. There are certain requirements for the supply line and it
>> must include at least a 20' buried run starting within 5' of where it
>> enters the building. The grounding electrode connector must connect
>> to the water supply line within 5' of its entering the building, and the
>> water meter must be bridged bonding both pipes (that entering the
>> meter and that leaving the meter).
>>
>> An Equipment ground (that third grounded hole in a modern
>> outlet) can be made to a cold water pipe as long as the pipe
>> is bonded to the grounding electrode.

>


>
> Does not matter that water pipe is 20 feet in earth. Earthing is a
> completely different ground from equipment (safety) ground.
> Electricty is different at both ends of a wire. Any connection from
> wall receptacles to earth ground must be via that common point bus bar
> ground inside main disconnect breaker box. This being only the first
> reason why receptacles are never bonded to a water pipe.


Comments are based on the US 2005 National Electrical Code.
For an existing 2 wire circuit, a separate ground wire can be added that
connects anywhere on the grounding electrode system. That includes the
heavy wire to earthing electrodes. The NEC explicitly includes the water
pipe within 5 feet of the entrance to the house. In the past, connection
anywhere on metal water piping was permitted.


>
> Third, bonding a water pipe to breaker box serves a critical human
> safety function. If dangerous electrical currents exist due 'fault'
> into a pipe, then the bare copper wire that connects water pipe to
> that breaker box bus bar will also protect humans - also connect fault
> currents to the common safety ground bus bar. Its purpose is to remove
> dangerous voltages from pipes. If that voltage is created by a fault
> current is dumped into pipes by another wire, then that wiring fault
> must be corrected / removed / disconnected. That latter wire
> violates code and may even result in loss of insurance coverage. All
> connections to water pipes - including the bypass around meter and
> bypass around water heater - are part of a system (newer requirements)
> only to *remove* electricity from pipes. Never dump a fault current
> into pipes. That means never connect a receptacle ground or electrical
> appliance ground to pipes. Never. And yes, that is a change from
> code so many generations ago.


“Remove electricity from pipes” is remarkably unclear writing. Anyone
competent in technical fields could do better.

Underground metal water pipe at least 10 feet length buried has for a
*very* long time been *required* to be used as a *grounding electrode*.
In the common case of an urban metal water supply system it will have a
far lower resistance to earth than any other electrode available at a
house. The connection for many years has been required to be within 5
feet of the entrance to the building with a bond across the water meter.

(If the underground pipe is not 10 feet metal the interior water pipe
must still be “bonded” to the service ground under almost the same rules
as if it was a grounding electrode.)

Because metal water service pipe may in the future be replaced with
plastic, for many years a “supplemental” electrode has been required.
This used to be 1 or 2 ground rods which are often only slightly better
than nothing. Starting with the 2005 NEC a Ufer/concrete encased
electrode has also been required for new construction with footings or
foundations. This is a good electrode.

>
> Fourth, no matter what pipe a plumber disconnects, disconnected pipe
> must never compromise any safetyl grounds. If any safety ground is
> dependent on a pipe, then a code violation exists.


w_ apparently does not live anywhere the US NEC is enforced.


To the OP:

A ground to the outlet can be by metal sheath or a cable with a separate
ground wire. You can get an idea in the basement what wiring system you
have, although having a good ground in the basement does not guarantee
the ground is continued to the outlet in question.

If no ground is present can you move the computer to an area where a
good ground is present? Or where it is easier to add a ground?

It is a code and safety violation violation for someone to have added a
“grounded” outlet where there is no ground. A grounded–type GFCI
outlet can be installed, however, adding the sticker provided with the
outlet “No equipment ground”.

The ground test on a surge protector as well as the ground test on a
plug-in outlet tester will likely correctly indicate a problem.
Indicating a ‘good’ ground is not necessarily reliable because they test
at a very low current and will indicate ‘good’ on a very high ground
resistance.

--
bud--


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