Ground Or Neutral Wire Question

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Hello,
Just want to get the terminology correct.
Understand the differences between the Ground and the neutral in house wiring O.K., but for the bare wire that comes in from the street (along with the two phases) to the house service panel:
is this correctly called a Ground wire or a Neutral wire ?
Thanks, Bob
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It is a grounded conductor commonly called the neutral. The wire that connects to your water pipe and ground rods is called a grounding conductor or more specifically a grounding electrode conductor.
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John Grabowski wrote:

now. I prefer to only use ground rods anyway.
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Correction: if a building has metal water pipes, it is a Code requirement (and has been, for some time) that the metal water pipes be bonded to the building's grounding electrode system. The Code prohibits using metal water piping as the *only* grounding electrode.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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On Thu, 23 Feb 2006 13:00:16 GMT, snipped-for-privacy@milmac.com (Doug Miller) wrote:

Which in clear but imprecise terms, means that the the piping has to be CONNECTED to the grounding system, but shouldn't be used as PART of it. You connect the pipes to ground, but you don't ground to the pipes.
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Goedjn wrote:

If the incoming underground water pipes are metal, one most certainly grounds the electric system "to the pipes". In fact NEC requires that underground metal water pipes (buried at least 20 ft.) be used as the primary grounding electrode when available.
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Are you sure? I don't have a copy of NEC here, but what I remember was verbage more like this:
"If ten feet of metal underground water pipe is available, it must be used as a grounding electrode; however, it must always be supplemented by an additional electrode."
--- from: http://www.ventura.org/vcrma/build_safe/pdf/new_handouts_info/e-7.pdf
Either way, the functional bottom line is that connecting the service-panel ground to the pipes is sometimes necessary, but never sufficient. I was under the impression that the purpose of that was to get electricity OFF the pipes, rather than to provide an additional path to ground.
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Goedjn wrote:

I have no idea what "get electricity OFF the pipes" means.
You are right about 10' - in the post of Rich256 the water pipe (plastic) is not a grounding electrode.
Of the electrodes normally available in a house, the best by far is 10' or more of underground water pipe (doesn't have to buried 20') and if such pipe exists it MUST be part of the grounding electrode system. This was the only required grounding electrode until recently.
The ONLY reason a suplementary electrode is necessary is that the metal water pipe may in the future be replaced by plastic (as Tom Horne said). Note the term "supplementary". If the water pipe is metal the supplementary electrode adds little or nothing.
Of the "supplementary" electrodes that can be used, probably the worst is a ground rod because of high ground resistance. Unfortunately it is the easiest to provide. Far better. with a long term tested ground resistance of 5 ohms, is a concrete-encased electrode (Ufer ground). These are easy to include in new construction. Next best is probably a ground ring - also easy to provide in new construction.
bud--
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Recent electrical code revisions appear to be prefering grounding plates over rods. These plates are approx 12" square by 1/4" thick.
More surface area than a rod. Somewhat trickier to install - undisturbed dirt contact, not just flung in the backfill.
--
Chris Lewis, Una confibula non set est
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Bud-- wrote:

I believe that this is the activity of making sure that the water coming out of your shower is the same electrically as your ground.
That way, you do not get shocked just because you left hand is in the water while your right hand is holding the shaver with a case ground.
AC mean that 30 time a second that one wire is +, the other 30 times a second it is -.
Now, that timing needs to be the same as your water supply. That way, when your water is +, so is everything else.
No current flow possible.
If it is +, when everything else is -, then you get shocked.
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CanopyCo wrote:

No. 60 times a second one wire is + and 60 times a second that same wire is negative. The other is always at ground potential. The hot wire actually gets to about 170 volts positive and 170 volts negative during those swings. The RMS voltage being 120 volts.
Or about 162 volts peak if we refer to it as 115 volts AC.
A quick look shows there are quite a few web sites that describe this:
http://www.ee.unb.ca/tervo/ee2791/vrms.htm
Now if you have 240 volt service one of the hots gets 170 volts positive and at the same time the other line is 170 volts negative. They both cross the 0 volts at the same time. So if you are looking at them relative to each other the one line gets to be 340 volts different than the other.
In Europe with 230 volt service one line is grounded and the other gets to 325 volts at 50 cycles (Hz). Or about 310 volts peak if you refer to it as 220 volts.
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Goedjn wrote:

two driven rods is often over fifty ohms. The grounding impedance of underground metal water pipes that are part of a community water system is usually less than ten ohms. Changing what we say does not reverse those figures. It is the underground metal water piping that provides the low impedance connection to earth. The driven rods are strictly a back up in case the piping is replaced with non conductive piping. -- Tom Horne
--
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for general use." Thomas Alva Edison
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MC wrote:

I have seen 3 ohms stated as a typical ground resistance for an urban metal water distribution system. The NEC considers 25 ohms ground resistance acceptable for a single ground rod, or you can use more than 2 rods and it doesn't matter. Would seem like a water pipe is a better grounding electrode.
bud-
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Water line MUST be unified to electrical ground, and a jumper MUST be placed across the water meter so that ground is still good if the meter is removed and elmnates meter rubber washer interfying with a good connection
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snipped-for-privacy@aol.com wrote:

And city code here requires electrical isolation from the water system. Meters, installed at the street, have about 10 feet of plastic pipe before they make connection with the copper pipes going to the house.
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MC wrote:

In any installation governed by the US National Electric Code you must use the underground metallic water piping as a grounding electrode. Not using it is not a choice you would have. -- Tom Horne
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It is a neutral, which is grounded by the utility company on their end and grounded by the customer on their end

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It is a neutral and caries the difference in current back from the 2 hot legs. If you have a 100 amp service and one leg is at 60 amp and the other is at 40 amp then the neutral is 20 amps. If both legs are equal the current in the neutral cancels out to 0 amps etc.
The 2 legs are not really 2 phases but rather 2 poles that are derived, by a center tapped transformer, from ONE the 3 phases that come from the power generation plant. The center tap being the neutral and grounded so it is at a 0V reference.
Kevin
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Neither. John Grabowski's response is correct, but I thought I'd amplify.
The technically correct term for the "neutral" in the house wiring, and the "non-hot" wire that comes from the street is "grounded conductor" - the conductor is groundED (at the panel).
The technically correct term for the bare wire in house wiring is "grounding conductor" it provides the groundING for a circuit.
Pedantically speaking, the term "neutral" can only be applied to the center conductor on a multi-phase circuit (eg: three phase).
However, through common usage in the trade and elsewhere, "neutral" has come to be synonymous with "grounded conductor" and "ground"/"ground wire" synonymous for "grounding conductor".
You'll occasionally see people use the "more-correct" terms here - usually confuses people. You'll impress the inspector if you use them ;-)
--
Chris Lewis, Una confibula non set est
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people in the electrical trade (electricians, linemen, engineers, writers, etc.) to refer to a grounded conductor, whether it is a center-tap or end connection. This usage basically means "not hot", or relatively safe.
Don Young
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