blueman wrote: > Jeff Wisnia <jwis...@conversent.net> writes:
>>Brad wrote:
>>> Both pipes should be at the same electric potential (ground) since >>>they are both are buried.
>>Wrong, wrong...
>>Someone already mentioned the words "cathodic protection" with respect >>to gas pipes.
>>What that means is that the gas company has connected a low voltage >>source between a metal anode buried in the earth and the gas main and >>the pipes leading off it to each user. The purpose is to make the >>pipes slightly more electrically negative than ground so that they >>don't get eaten away by galvanic corrosion.
>>The same sort of active protection is sometimes used at boat marinas >>and on buried metal structures like guy wire anchors. The systems are >>also known by the names "active cathodic protection" or "impressed >>current protection".
>>There's a dielectric (insulated) coupling somewhere near the gas meter >>to insulate the gas pipe in your house from the buried main and feeder >>so that you don't "short out" that deliberately applied protection >>voltage, because the gas pipe in your home probably gets electrically >>grounded through some gas appliance it's connected to.
>>The use of plastic buried gas piping has eliiminated the need for >>those kinds of corrosion protection systems on new work.
>>>The grounding is done to help ensure the electrical panel has a true >>>ground. >>> In some cases the panel ground is wired to a long steel pole driven >>>into the earth. Just different ways to do the same thing. >>>Brad
> According to your explanation, then I would think that the gas pipe > SHOULD be grounded. For you say that the in-house pipe is insulated > from the underground piping and hence NEITHER grounded nor "cathodic > protected".
> Of course the pipe may end up being indirectly grounded through an > appliance ground, but that seems like all the more reason for > installing a solid, secure, permanent ground connection to the panel > ground. After all, what if the appliance is miswired and the appliance > ground is energized resulting in the pipe being energized (yet > insulated from earth ground), resulting in shock just like with a > water pipe...
I agree with you on that providing as you say, the grounding is done on the house side of any insulated coupling.
I was responding the the "buried thus same potential" statement, and should have made mention of the what you just did, that an "extra" ground between the panel ground and the in-house gas piping can't hurt, and may even be required by code.
Jeff
-- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) "Rudeness is the weak man's imitation of strength."
There are two issues here. Providing a good ground for your electrical service *and* grounding metal pipes in the house to prevent them from becoming energized.
Grounding your electrical service...
In the old days when all pipes were metal, a cold water pipe ground would do. But then there were problems with rubber grommets on water meters in basements isolating the inside water piping from the outside water piping, plastic piping run outside underground, and the ground wires becoming disconnected or damaged say by a lawnmower or whatever.
So a better grounding solution was found. That is a cold water pipe ground *and* a separate ground wire run from the electrical service panel to two ground rods placed 6 ft. apart. (double back-up) Also a ground wire which electrically connects the water pipe before the water meter to the water pipe after the water meter.
Grounding metal pipes/objects in the house to prevent them from becoming energized...
The idea of a 3rd prong on an electrical plug (ground wire) for an electrical appliance is that the metal case of the appliance is grounded. Then should there be a loose wire which touches the metal case and a person walks up and touches the metal case, the person will not be electrocuted. Or it would trip the breaker also protecting someone from being electrocuted.
Same thing with metal pipes or objects in a house. It is possible that a hot water pipe (which might be isolated because of rubber grommets) could become energized. So it is a good idea to run a ground wire from the cold water pipe to the hot water pipe (in homes with metal piping).
Hot and cold water pipes are very accessible to people. Sinks, washing machine, etc. Although gas pipes are not readily accessible to people, I suppose it wouldn't hurt anything to ground this as well. If grounding the gas pipe, I think running a ground wire from the gas pipe (house side of meter) to the ground rods or to a cold water pipe ground would be best. I don't think it would be a good idea to run a separate ground wire from the electric panel to a gas pipe.
Also while grounding things in the house, it is very important to ground metal objects around sinks and especially the bathroom. Like metal medicine cabinets which have a built in light fixture. The heat from light bulbs can cause insulation on wiring to melt away, then the metal cabinet can become energized. In a bathroom you are in bare feet and might be turning on the water while opening the medicine cabinet with the other hand - zap!
What can go wrong...
I have seen ground wires from main electrical service panels become disconnected. There could be a situation where the ground wire(s) from the main service panel become disconnected but someone ran a ground wire from there to something else like a gas pipe. Then an appliance could malfunction and this in turn could cause the gas pipe to become energized (if it was not inadvertently grounded via an appliance). So for this reason it is *not* a good idea to ground things such as this to a connection in the electrical panel, but to ground them directly to a ground such as cold water pipe and/or the ground rods.
Also you can get different "ground potentials". The ground at point A may be slightly different electrically from the ground at point B. For this reason, it is a good idea to ground everything at one point. That is run all ground wires or bond various grounds to say the ground rods or a main grounding point.
blueman <NOS...@nospam.com> wrote: >I read somewhere that one should also run a similar grounding wire to >the natural gas pipe inlet but the electrician didn't do that. >- Is it required by code?
No.
>- Is it recommended?
No, each utility does its own thing. Let the phone, and cable companies run their own grounds, to the unified ground of the electrical system.
Grounding is much less a concern to the gas company with their underground architecture than it is to the electric and phone companies with their aerial ones.
>- Should one use the same gauge wire as for the water pipe?
Yes, same gauge wire for all your grounding runs.
>- Any special considerations?
The galvanic corrosion problem mentioned refers mixing the types of materials on the pipes and wires, don't use a copper grounding clamp on an iron pipe, and vice versa.
>- Can I daisy chain it from the water pipe or do I need to run a > separate ground back to the panel?
A gas appliance, such as a furnace or range, that has an electrical hookup, will ground the gas line(s) that are connected to it, so you don't need to worry about it.
You need to "jump" over anything that is removable, such as the water meter, and the water heater, so that the plumbing is always grounded even if something is removed.
> "John Grabowski" <jgrabo...@optonline.net> writes: > > The correct term is "Bonded". The current code as written requires that all > > interior metal piping be bonded together. This can be accomplished by using > > #6 copper wire and approved clamps. It is common in New Jersey to bond the > > hot and cold water pipes together at the water heater location. It would be > > very easy to continue the bonding wire to the gas pipe at the water heater. > > Some jurisdictions do not require that the gas pipe also be bonded. Some > > gas companies do not want their pipes bonded. The electrical inspector would > > have noticed this and would have failed the job if it wasn't done correctly.
> > Did the electrician also install at least one (Preferably two) ground rod?
> Do you need to explicitly bond the hot and cold pipes together using a > copper wire jumper, or is there electrical continuity through the war > heater? (Note my house is all copper pipes)
Usually there is continuity through the water heater, however it is not an approved connection. You must use a #6 copper or #4 aluminum wire with approved water pipe ground clamps.
> Also can I bond the gas pipe to the subpanel indirectly by just > jumpering the gas water heater intake pipe to the cold water pipe > entering the hot water heater?
That is how I do it. I usually run one continuous piece of bare wire through each clamp on the hot water pipe, cold water pipe, and the gas pipe on the water heater. When the inspector comes he goes straight for the water heater and sees the bonding. If you have a hot water heating system and/or a well, those pipes need to be bonded with the others as well. Try and keep the clamps back far enough so that they will not interfere and do not have to be removed to change out the water heater.
> Or is it required to directly bond the gas intake pipe at the meter to > the panel ground using a single wire?
> Or is all of this unnecessary since the water heater itself provides a > conducting path bonding the gas pipe system to the water pipe system > (and then back through the water pipe to the panel ground)
In New Jersey the above bonding is required. Check with your local electrical inspector to learn what is required in your area.
There should also be a jumper wire from one side of your water meter to the other.
> "John Grabowski" <jgrabo...@optonline.net> writes: > > "blueman" <NOS...@nospam.com> wrote in message > > news:u3bchwwob.fsf@nospam.com... > > > When we had our electric service upgraded, the electrician (as > > > expected) ran a ground wire from the cold water main inlet to the > > > ground on the panel.
> > > I read somewhere that one should also run a similar grounding wire to > > > the natural gas pipe inlet but the electrician didn't do that. > > > - Is it required by code? > > > - Is it recommended? > > > - Should one use the same gauge wire as for the water pipe? > > > - Any special considerations? > > > - Can I daisy chain it from the water pipe or do I need to run a > > > separate ground back to the panel?
> > > Thanks
> > The correct term is "Bonded". The current code as written requires that all > > interior metal piping be bonded together. This can be accomplished by using > > #6 copper wire and approved clamps. It is common in New Jersey to bond the > > hot and cold water pipes together at the water heater location. It would be > > very easy to continue the bonding wire to the gas pipe at the water heater. > > Some jurisdictions do not require that the gas pipe also be bonded. Some > > gas companies do not want their pipes bonded. The electrical inspector would > > have noticed this and would have failed the job if it wasn't done correctly.
> > Did the electrician also install at least one (Preferably two) ground rod?
> The electrician installed one exterior copper rod sunk in the ground > and attached directly to the 200A main breaker (which is exterior to > the house in a box with the meter) and then a second copper wire > running from where the water source enters the house (old galvanized > 1" metal pipe) to the grounding strip within the 200A Subpanel.
> Note that all other subpanels feed off of the 200A Subpanel. > Note I have also shown where the neutral and grounds are bonded at the > main breaker.
> Does this make sense and is it legal?
I think that the water pipe grounding conductor should have been connected at the same point as the ground rod conductor at the main breaker in order to be code compliant.
Are the neutral conductor and the water pipe grounding conductor terminated separately so as to be isolated electrically from each other in the 200 amp subpanel?
John Grabowski wrote: >> In New Jersey the above bonding is required. Check with your local > electrical inspector to learn what is required in your area.
> There should also be a jumper wire from one side of your water meter to the > other.
The advice to check with the local inspector (AHJ "Authority Having Jurisdiction" in electrical-speak) is proably the best advice.
For those that want to read about it, EC&M (Electrical Contracting and Maintenance Magazine) has this article -
John Grabowski wrote: > "blueman" <NOS...@nospam.com> wrote in message > news:u3bchwwob.fsf@nospam.com... > > When we had our electric service upgraded, the electrician (as > > expected) ran a ground wire from the cold water main inlet to the > > ground on the panel.
> > I read somewhere that one should also run a similar grounding wire to > > the natural gas pipe inlet but the electrician didn't do that. > > - Is it required by code? > > - Is it recommended? > > - Should one use the same gauge wire as for the water pipe? > > - Any special considerations? > > - Can I daisy chain it from the water pipe or do I need to run a > > separate ground back to the panel?
> > Thanks
> The correct term is "Bonded". The current code as written requires that all > interior metal piping be bonded together. This can be accomplished by using > #6 copper wire and approved clamps. It is common in New Jersey to bond the > hot and cold water pipes together at the water heater location. It would be > very easy to continue the bonding wire to the gas pipe at the water heater. > Some jurisdictions do not require that the gas pipe also be bonded. Some > gas companies do not want their pipes bonded. The electrical inspector would > have noticed this and would have failed the job if it wasn't done correctly.
> Did the electrician also install at least one (Preferably two) ground rod?
ive found most inspectorsdo not enforce this code here and some are requiring only one ground rod we still use two but ground rods are nearly worthless,certain conditions dont matter how many you drive down you still dont get the 25 or less ohms to ground
"John Grabowski" <jgrabo...@optonline.net> writes: > "blueman" <NOS...@nospam.com> wrote in message > > The electrician installed one exterior copper rod sunk in the ground > > and attached directly to the 200A main breaker (which is exterior to > > the house in a box with the meter) and then a second copper wire > > running from where the water source enters the house (old galvanized > > 1" metal pipe) to the grounding strip within the 200A Subpanel.
> > Note that all other subpanels feed off of the 200A Subpanel. > > Note I have also shown where the neutral and grounds are bonded at the > > main breaker.
> > Does this make sense and is it legal?
> I think that the water pipe grounding conductor should have been connected > at the same point as the ground rod conductor at the main breaker in order > to be code compliant. > Are the neutral conductor and the water pipe grounding conductor terminated > separately so as to be isolated electrically from each other in the 200 amp > subpanel?
Yes. That is what I was trying to show in the picture.
On Mon, 31 Jul 2006 16:45:10 GMT, blueman <NOS...@nospam.com> wrote: >When we had our electric service upgraded, the electrician (as >expected) ran a ground wire from the cold water main inlet to the >ground on the panel.
>I read somewhere that one should also run a similar grounding wire to >the natural gas pipe inlet but the electrician didn't do that. >- Is it required by code? >- Is it recommended? >- Should one use the same gauge wire as for the water pipe? >- Any special considerations? >- Can I daisy chain it from the water pipe or do I need to run a > separate ground back to the panel?
>Thanks
Only qualified allow qualified personnel work on electrical systems, and follow all construction codes.
IMHO:
1. Required per 2005 NEC 250.104(B) 2. Required. 3. Per 250.104(b) use 250.122 as source of size. 4. Nothing special, but ensure you follow the NEC and local codes. Give your local code enforcement inspector a call. 5. 250.104(B) tells you the options you have to bonding the metal piping to. One includes bonding to the grouding electrode. If your water pipe meets the requirements of 250.52(A)(1), then it is a grounding electrode. So a water inlet piping can be used per code.
Now all this is using the NEC, and guessing about your local setup. Only a qualified person working on site can help you. So this is not a how-to, but a starting point for planning your operation. Research with your local inspector, or AHJ.
>>>> Both pipes should be at the same electric potential (ground) since >>>>they are both are buried. >>>>The grounding is done to help ensure the electrical panel has a true >>>>ground.
>>>Wrong, wrong, wrong, wrong.
>>>The water piping is bonded to the electrical ground in order to insure that >>>the _water_piping_ has a true electrical ground -- IOW, to prevent the water >>>piping from becoming live in the event of an electrical fault somewhere.
>>The first poster had it right. The water piping is already at ground because >>it is in direct contact with the ground. Unless of course you have >>your water brought to you on pipes suspended in the air. Or perhaps you >>have it flown in?
> No, he didn't. The electrical system has its own, *separate* grounding > electrode. Metal water piping is bonded to the electrical system grounding > electrodes to ensure that the metal water piping cannot become live, *not* to > provide a ground for the electrical system.
> BTW... have you ever heard of plastic water piping?
The NEC has for a very long time required that water service pipes be used as a grounding electrode. The current code REQUIRES that water service pipe with metal pipe underground length of 10 ft or more be included as a grounding electrode. Because this pipe may in the future be replaced with plastic pipe, a supplemental electrode is required - usually ground rod(s). For new construction use a Ufer ground/concrete encased electrode. These electrodes are connected together to make a grounding electrode system. The earthing resistance of a metal municipal water system is lower than anything you can provide in a house.
>>>>When we had our electric service upgraded, the electrician (as >>>>expected) ran a ground wire from the cold water main inlet to the >>>>ground on the panel.
>>>>I read somewhere that one should also run a similar grounding wire to >>>>the natural gas pipe inlet but the electrician didn't do that. >>>>- Is it required by code? >>>>- Is it recommended? >>>>- Should one use the same gauge wire as for the water pipe? >>>>- Any special considerations? >>>>- Can I daisy chain it from the water pipe or do I need to run a >>>> separate ground back to the panel?
>>>>Thanks
>>>The correct term is "Bonded". The current code as written requires that
> all
>>>interior metal piping be bonded together. This can be accomplished by
> using
>>>#6 copper wire and approved clamps. It is common in New Jersey to bond
> the
>>>hot and cold water pipes together at the water heater location. It would
> be
>>>very easy to continue the bonding wire to the gas pipe at the water
> heater.
>>>Some jurisdictions do not require that the gas pipe also be bonded.
> Some
>>>gas companies do not want their pipes bonded. The electrical inspector
> would
>>>have noticed this and would have failed the job if it wasn't done
> correctly.
>>>Did the electrician also install at least one (Preferably two) ground
> rod?
>>The electrician installed one exterior copper rod sunk in the ground >>and attached directly to the 200A main breaker (which is exterior to >>the house in a box with the meter) and then a second copper wire >>running from where the water source enters the house (old galvanized >>1" metal pipe) to the grounding strip within the 200A Subpanel.
>> Service Entrance >> 200A Main Breaker 200A Subpanel 100A Subpanel >>Neurtral----->[----------]---------->[-----------]--------->[-----------] >> [ | ] [ ] [ ] >>Earth grnd -->[--------- ]---------->[-----------]--------->[-----------] >> | >> Water pipe -----|
>>Note that all other subpanels feed off of the 200A Subpanel. >>Note I have also shown where the neutral and grounds are bonded at the >>main breaker.
>>Does this make sense and is it legal?
> I think that the water pipe grounding conductor should have been connected > at the same point as the ground rod conductor at the main breaker in order > to be code compliant.
I agree. The NEC requires the water service pipe (if 10 ft or more length underground) to be connected to the ground/neutral at the service disconnect, along with the ground rod. Also connecting it to the ground bar in the subpanel is OK.
In article <d1e97$44d4ba17$4213eb55$24...@DIALUPUSA.NET>, Bud-- <remove.BudN...@isp.com> wrote: >The NEC has for a very long time required that water service pipes be >used as a grounding electrode.
Note the word "a". Not "the".
> The current code REQUIRES that water >service pipe with metal pipe underground length of 10 ft or more be >included as a grounding electrode.
And it flatly prohibits using it as the *only* grounding electrode.
>Because this pipe may in the future >be replaced with plastic pipe, a supplemental electrode is required - >usually ground rod(s).
You have things backwards. The ground rod is the *primary* grounding electrode, and the water piping is the supplemental electrode.
You're also wrong about the reason.
"Bonding of piping systems... the basic concept is to ground any metal pipes that would present a hazard if energized by an electrical circuit." [National Electrical Code Handbook, Section 250-80]
I don't know how to put it any simpler than that.
-- Regards, Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
Jeff Wisnia <jwis...@conversent.net> writes: > blueman wrote: > > Jeff Wisnia <jwis...@conversent.net> writes:
> >>Brad wrote:
> >>> Both pipes should be at the same electric potential (ground) since > >>>they are both are buried.
> >>Wrong, wrong...
> >>Someone already mentioned the words "cathodic protection" with respect > >>to gas pipes.
> >>What that means is that the gas company has connected a low voltage > >>source between a metal anode buried in the earth and the gas main and > >>the pipes leading off it to each user. The purpose is to make the > >>pipes slightly more electrically negative than ground so that they > >>don't get eaten away by galvanic corrosion.
> >>The same sort of active protection is sometimes used at boat marinas > >>and on buried metal structures like guy wire anchors. The systems are > >>also known by the names "active cathodic protection" or "impressed > >>current protection".
> >>There's a dielectric (insulated) coupling somewhere near the gas meter > >>to insulate the gas pipe in your house from the buried main and feeder > >>so that you don't "short out" that deliberately applied protection > >>voltage, because the gas pipe in your home probably gets electrically > >>grounded through some gas appliance it's connected to.
> >>The use of plastic buried gas piping has eliiminated the need for > >>those kinds of corrosion protection systems on new work.
> >>>The grounding is done to help ensure the electrical panel has a true > >>>ground. > >>> In some cases the panel ground is wired to a long steel pole driven > >>>into the earth. Just different ways to do the same thing. > >>>Brad > > According to your explanation, then I would think that the gas pipe > > SHOULD be grounded. For you say that the in-house pipe is insulated > > from the underground piping and hence NEITHER grounded nor "cathodic > > protected". > > Of course the pipe may end up being indirectly grounded through an > > appliance ground, but that seems like all the more reason for > > installing a solid, secure, permanent ground connection to the panel > > ground. After all, what if the appliance is miswired and the appliance > > ground is energized resulting in the pipe being energized (yet > > insulated from earth ground), resulting in shock just like with a > > water pipe...
> I agree with you on that providing as you say, the grounding is done > on the house side of any insulated coupling.
> I was responding the the "buried thus same potential" statement, and > should have made mention of the what you just did, that an "extra" > ground between the panel ground and the in-house gas piping can't > hurt, and may even be required by code.
> Jeff
Well, I called our local gas company (Keyspan) and after a few handoffs, I was told that they do NOT recommend grounding the gas pipe. In fact, they say that if they see such a bridging on a service call, they typically remove it.
Doug Miller wrote: > In article <d1e97$44d4ba17$4213eb55$24...@DIALUPUSA.NET>, Bud-- <remove.BudN...@isp.com> wrote:
>>The NEC has for a very long time required that water service pipes be >>used as a grounding electrode.
> Note the word "a". Not "the".
So what? Metal water service pipes (10 ft or longer) are REQUIRED by 250.50 to be a part of the grounding electrode system. This basic requirement has been in the code for a very long time. Ground rods are not required to be installed.
>>The current code REQUIRES that water >>service pipe with metal pipe underground length of 10 ft or more be >>included as a grounding electrode.
> And it flatly prohibits using it as the *only* grounding electrode.
So what? See reason.
>>Because this pipe may in the future >>be replaced with plastic pipe, a supplemental electrode is required - >>usually ground rod(s).
> You have things backwards. The ground rod is the *primary* grounding > electrode, and the water piping is the supplemental electrode.
You have things backwards. With a water pipe a "supplemental" electrode is required - 250.53-D-2. A "supplemental" ground rod is a strange name for the "primary" grounding electrode.
Grounding rods are 'good' if their resistance to earth is 25 ohms or less (or use 2 rods and it doesn't matter). Municipal water pipe earth resistance is typically under 3 ohms.
Grounding electrode conductors to a water pipe must be up to 3/0 copper for large services. For a ground rod they can be #6 Cu for any service. For a Ufer ground #4 Cu.
A ground rod is not required, only another electrode. A much better choice for new construction is a Ufer ground/concrete-encased electrode. Presumably the NEC language has been changed to require Ufer grounds for new construction (if there is a foundation or footing). [Are AHJs requiring Ufer?] Ufer earth resistances are likely under 5 ohms.
> You're also wrong about the reason.
From the National Electrical Code Handbook - 1996 publushed by the NFPA under 250.81(a) [in 1999 this morphed into 2005-250.52-A-1] “The requirement to supplement the metal water pipe is based on the practice of using plastic pipe for replacement when the original metal water pipe fails. This leaves the system without a grounding electrode unless a supplementary electrode is provided.”
(Note that the ground rod is a "supplementary" electrode.)
> "Bonding of piping systems... the basic concept is to ground any metal pipes > that would present a hazard if energized by an electrical circuit." [National > Electrical Code Handbook, Section 250-80]
If the water service pipe is plastic and there is interior metal water pipe it is required to be bonded by 250.80. If the water service pipe is metal (10 ft...) it is REQUIRED by 250.50 to be a part of the grounding electrode system and 250.80 is irrelevant.
> I don't know how to put it any simpler than that.
In article <aa45$44d59bfc$4213ea8c$30...@DIALUPUSA.NET>, Bud-- <remove.BudN...@isp.com> wrote: >Doug Miller wrote:
>> In article <d1e97$44d4ba17$4213eb55$24...@DIALUPUSA.NET>, Bud-- > <remove.BudN...@isp.com> wrote:
>>>The NEC has for a very long time required that water service pipes be >>>used as a grounding electrode.
>> Note the word "a". Not "the".
>So what? Metal water service pipes (10 ft or longer) are REQUIRED by >250.50 to be a part of the grounding electrode system. This basic >requirement has been in the code for a very long time.
"A part", yes -- but it is not permitted to be the *only* grounding electrode.
> Ground rods are >not required to be installed.
Technically true, but misleading. You may use a ground rod, a ground plate, a buried wire ring, or the metal framing of the building, as the *only* grounding electrode. But not a water pipe.
>>>The current code REQUIRES that water >>>service pipe with metal pipe underground length of 10 ft or more be >>>included as a grounding electrode.
>> And it flatly prohibits using it as the *only* grounding electrode.
>So what? See reason.
>>>Because this pipe may in the future >>>be replaced with plastic pipe, a supplemental electrode is required - >>>usually ground rod(s).
>> You have things backwards. The ground rod is the *primary* grounding >> electrode, and the water piping is the supplemental electrode.
>You have things backwards. With a water pipe a "supplemental" electrode >is required - 250.53-D-2. A "supplemental" ground rod is a strange name >for the "primary" grounding electrode.
The Code permits using a ground rod, alone, as the grounding electrode. It prohibits using a water pipe, alone, as the grounding electrode. Quibbling over which is "primary" and which is "supplemental" doesn't change those facts.
>Grounding rods are 'good' if their resistance to earth is 25 ohms or >less (or use 2 rods and it doesn't matter). Municipal water pipe earth >resistance is typically under 3 ohms.
Irrelevant. The Code does not permit a water pipe to be the only grounding electrode.
Again:
>> "Bonding of piping systems... the basic concept is to ground any metal pipes >> that would present a hazard if energized by an electrical circuit." [National >> Electrical Code Handbook, Section 250-80]
I'm not sure why you're having so much trouble grasping this.
-- Regards, Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
Assume underground metal water service pipe (10ft...) and a ground rod.
Your original statement was:
> Metal water piping is bonded to the electrical system grounding > electrodes to ensure that the metal water piping cannot become live, > *not* to provide a ground for the electrical system
The underground water service pipe is REQUIRED by the 250.50 to be included as a grounding electrode. It has been thus fire was invented. Bonding requirements under 250.104-A (not 250.80) have been already met under the more stringent 250.50. The code clearly requires the water service pipe to be a grounding electrode. The water pipe clearly provides “A GROUND FOR THE ELECTRICAL SYSTEM.”
If 250.104 was removed, the connection would still have to be made. If the water service pipe was plastic 250.104 would prevail.
Both Brad and AZNomad said the water pipe was a grounding electode. So far no one agrees with you.
You said: > The ground rod is the *primary* grounding > electrode, and the water piping is the supplemental electrode.
250.53-D-2. requires a "supplemental" electrode - your ground rod. The water pipe is clearly superior based on the size of grounding electrode conductor required for each electrode and by typical earth resistances.
You said: > You're also wrong about the reason The NFPA Handbook said the rod was there because the water pipe might be replaced in the future with plastic with the rod as a "supplementary" fall-back.
I'm not sure why you're having so much trouble grasping this.
In article <22cab$44d6791d$4213ea37$9...@DIALUPUSA.NET>, Bud-- <remove.BudN...@isp.com> wrote: >Assume underground metal water service pipe (10ft...) and a ground rod.
>Your original statement was:
> > Metal water piping is bonded to the electrical system grounding > > electrodes to ensure that the metal water piping cannot become live, > > *not* to provide a ground for the electrical system
Yep. And that's correct.
The water pipe -- by itself -- is not permitted by Code to be used to ground the electrical system, and hasn't been for many years.
It's bonded to the *other* grounding electrode(s) to ensure that the water piping is always at zero potential with respect to the electrical ground.
Not sure why you're having such a hard time grasping that concept...
-- Regards, Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
Doug Miller wrote: > In article <22cab$44d6791d$4213ea37$9...@DIALUPUSA.NET>, Bud-- <remove.BudN...@isp.com> wrote:
>>Assume underground metal water service pipe (10ft...) and a ground rod.
>>Your original statement was:
>>>Metal water piping is bonded to the electrical system grounding >>>electrodes to ensure that the metal water piping cannot become live, >>>*not* to provide a ground for the electrical system
> Yep. And that's correct.
> The water pipe -- by itself -- is not permitted by Code to be used to ground > the electrical system, and hasn't been for many years.
2005 NEC 250.50 "All grounding electrodes as described in 250.52(A)(1) through (A)(6) shall be bonded together to to form the grounding electrode system."
250.52(A)(1) "Metal Underground Water Pipe. A metal underground water pipe indirect contact with the earth for 3.0 m (10 ft) or more...."
100(1) [definitions] "Grounding Electrode. A device that establishes an electrical connection to the earth."
If you are having trouble intrepreting: All grounding electrodes including Metal Underground Water Pipe shall be bonded together to to form the grounding electrode system that establishes an electrical connection to the earth.
In article <9f66a$44d7667d$4213ea86$15...@DIALUPUSA.NET>, Bud-- <remove.BudN...@isp.com> wrote: >Doug Miller wrote:
>> In article <22cab$44d6791d$4213ea37$9...@DIALUPUSA.NET>, Bud-- > <remove.BudN...@isp.com> wrote:
>>>Assume underground metal water service pipe (10ft...) and a ground rod.
>>>Your original statement was:
>>>>Metal water piping is bonded to the electrical system grounding >>>>electrodes to ensure that the metal water piping cannot become live, >>>>*not* to provide a ground for the electrical system
>> Yep. And that's correct.
>> The water pipe -- by itself -- is not permitted by Code to be used to ground >> the electrical system, and hasn't been for many years.
>2005 NEC 250.50 "All grounding electrodes as described in 250.52(A)(1) >through (A)(6) shall be bonded together to to form the grounding >electrode system."
>250.52(A)(1) "Metal Underground Water Pipe. A metal underground water >pipe indirect contact with the earth for 3.0 m (10 ft) or more...."
>100(1) [definitions] "Grounding Electrode. A device that establishes an >electrical connection to the earth."
>If you are having trouble intrepreting: All grounding electrodes >including Metal Underground Water Pipe shall be bonded together to to >form the grounding electrode system that establishes an electrical >connection to the earth.
>What do you think it means?
>Can you read?
You're the one who has trouble reading, not me. I never said that metal water pipes shouldn't be part of the grounding electrode system -- I said that metal water pipes are not permitted to be the *only* grounding electrode, and that's a fact.
It's also a fact that the reason for bonding metal water pipes to the other grounding electrode(s) is to ensure that the plumbing cannot ever become live, no matter what might go wrong with the electrical system.
Sorry you're having such a hard time understanding.
-- Regards, Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
[excerpt - see above link for full article] Changes to 250.50 were made to clarify that, where any of the following electrodes "are present" they must be bonded together to create the grounding electrode system.
Underground metal water pipe [250.52(A)(1)]
Metal frame of the building or structure [250.52(A)(2)]
Concrete-encased foundation or footer steel [250.52(A)(3)]
Ground ring [250.52(A)(4)]
Ground rod [250.52(A)(5)]
Grounding plate [250.52(A)(6)]
The intent of the change to 250.50 (wording changed from "if available" to "are present") and the addition of the exception was meant to require the use of concrete-encased foundation or footer steel as part of the building or structure grounding electrode system in new construction (if they are present), since they are considered "present" before they pour concrete.
>>>>Assume underground metal water service pipe (10ft...) and a ground rod.
>>>>Your original statement was:
>>>>>Metal water piping is bonded to the electrical system grounding >>>>>electrodes to ensure that the metal water piping cannot become live, >>>>>*not* to provide a ground for the electrical system
>>>Yep. And that's correct.
>>>The water pipe -- by itself -- is not permitted by Code to be used to ground >>>the electrical system, and hasn't been for many years.
>>2005 NEC 250.50 "All grounding electrodes as described in 250.52(A)(1) >>through (A)(6) shall be bonded together to to form the grounding >>electrode system."
>>250.52(A)(1) "Metal Underground Water Pipe. A metal underground water >>pipe indirect contact with the earth for 3.0 m (10 ft) or more...."
>>100(1) [definitions] "Grounding Electrode. A device that establishes an >>electrical connection to the earth."
>>If you are having trouble intrepreting: All grounding electrodes >>including Metal Underground Water Pipe shall be bonded together to to >>form the grounding electrode system that establishes an electrical >>connection to the earth.
>>What do you think it means?
>>Can you read?
> You're the one who has trouble reading, not me. I never said that metal water > pipes shouldn't be part of the grounding electrode system -- I said that metal > water pipes are not permitted to be the *only* grounding electrode, and that's > a fact.
Your fact is not consistent with what you said: “The electrical system has its own, *separate* grounding electrode. Metal water piping is bonded to the electrical system grounding electrodes to ensure that the metal water piping cannot become live, *not* to provide a ground for the electrical system.”
I do not see how "*not* to provide a ground for the electrical system" can be read other than the water pipe is not to be a grounding electrode and the system grounding is provided by the system's "own, *separate* grounding electrode."
In article <d900a$44d971d4$4213eb17$...@DIALUPUSA.NET>, Bud-- <remove.BudN...@isp.com> wrote: >Your fact is not consistent with what you said: >“The electrical system has its own, *separate* grounding electrode. >Metal water piping is bonded to the electrical system grounding >electrodes to ensure that the metal water piping cannot become live, >*not* to provide a ground for the electrical system.”
>I do not see how "*not* to provide a ground for the electrical system" >can be read other than the water pipe is not to be a grounding electrode >and the system grounding is provided by the system's "own, *separate* >grounding electrode."
It's real simple: the water pipe is bonded to the other grounding electrodes, not to provide a ground for the electrical system -- that's what the *other* electrodes are there for, remember? -- but to ensure that the metal water piping is always at the same potential as the electrical system's ground and therefore cannot become live no matter *what* might go wrong electrically.
I'm sorry that you're having such a hard time grasping this... but you really need to spend a little more time educating yourself before you post again.
-- Regards, Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
> [excerpt - see above link for full article] > Changes to 250.50 were made to clarify that, where any of the following > electrodes "are present" they must be bonded together to create the > grounding electrode system.
> Underground metal water pipe [250.52(A)(1)]
> Metal frame of the building or structure [250.52(A)(2)]
> Concrete-encased foundation or footer steel [250.52(A)(3)]
To me this wording is clearer than "concrete encased electrode", which to me implies that connection to the steel has been made available. Nothing else in the list is named as an "electrode".
> Ground ring [250.52(A)(4)]
> Ground rod [250.52(A)(5)]
> Grounding plate [250.52(A)(6)]
> The intent of the change to 250.50 (wording changed from "if > available" to "are present") and the addition of the exception > was meant to require the use of concrete-encased foundation or footer > steel as part of the building or structure grounding electrode system > in new construction (if they are present), since they are considered > "present" before they pour concrete.
IMHO the code should make this even more explicit. Good requirement though.
Doug Miller wrote: > In article <d900a$44d971d4$4213eb17$...@DIALUPUSA.NET>, Bud-- <remove.BudN...@isp.com> wrote:
>> Your fact is not consistent with what you said: >> The electrical system has its own, *separate* grounding electrode. >> Metal water piping is bonded to the electrical system grounding >> electrodes to ensure that the metal water piping cannot become live, >> *not* to provide a ground for the electrical system.
>> I do not see how "*not* to provide a ground for the electrical system" >> can be read other than the water pipe is not to be a grounding electrode >> and the system grounding is provided by the system's "own, *separate* >> grounding electrode."
> It's real simple: the water pipe is bonded to the other grounding electrodes, > not to provide a ground for the electrical system -- that's what the *other* > electrodes are there for, remember? -- but to ensure that the metal water > piping is always at the same potential as the electrical system's ground and > therefore cannot become live no matter *what* might go wrong electrically.
> I'm sorry that you're having such a hard time grasping this... but you really > need to spend a little more time educating yourself before you post again.
"250.50 Grounding Electrode System. If available on the premises at each building or structure served, each item in 250.52(A)(1) through (A)(6) shall be bonded together to form the grounding electrode system. 250.52 Grounding Electrodes. (A) Electrodes Permitted for Grounding. (1) Metal Underground Water Pipe. A metal underground water pipe in direct contact with the earth for 3.0 m (10 ft) or more (including any metal well casing effectively bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductors. Interior metal water piping located more than 1.52 m (5 ft) from the point of entrance to the building shall not be used as a part of the grounding electrode system or as a conductor to interconnect electrodes that are part of the grounding electrode system." Copyright 2002 National Fire Protection Association
Now who is it that needs to educate themselves? -- Tom Horne
"This alternating current stuff is just a fad. It is much too dangerous for general use." Thomas Alva Edison
In article <YwrCg.6565$0e5.3...@newsread4.news.pas.earthlink.net>, horn...@mindspring.com wrote: >Doug Miller wrote: >> In article <d900a$44d971d4$4213eb17$...@DIALUPUSA.NET>, Bud-- > <remove.BudN...@isp.com> wrote:
>>> Your fact is not consistent with what you said: >>> The electrical system has its own, *separate* grounding electrode. >>> Metal water piping is bonded to the electrical system grounding >>> electrodes to ensure that the metal water piping cannot become live, >>> *not* to provide a ground for the electrical system.
>>> I do not see how "*not* to provide a ground for the electrical system" >>> can be read other than the water pipe is not to be a grounding electrode >>> and the system grounding is provided by the system's "own, *separate* >>> grounding electrode."
>> It's real simple: the water pipe is bonded to the other grounding electrodes, >> not to provide a ground for the electrical system -- that's what the *other* >> electrodes are there for, remember? -- but to ensure that the metal water >> piping is always at the same potential as the electrical system's ground and >> therefore cannot become live no matter *what* might go wrong electrically.
>> I'm sorry that you're having such a hard time grasping this... but you really >> need to spend a little more time educating yourself before you post again.
>"250.50 Grounding Electrode System. >If available on the premises at each building or structure served, each >item in 250.52(A)(1) through (A)(6) shall be bonded together to form the >grounding electrode system. >250.52 Grounding Electrodes. >(A) Electrodes Permitted for Grounding. >(1) Metal Underground Water Pipe. A metal underground water pipe in >direct contact with the earth for 3.0 m (10 ft) or more (including any >metal well casing effectively bonded to the pipe) and electrically >continuous (or made electrically continuous by bonding around insulating >joints or insulating pipe) to the points of connection of the grounding >electrode conductor and the bonding conductors. Interior metal water >piping located more than 1.52 m (5 ft) from the point of entrance to the >building shall not be used as a part of the grounding electrode system >or as a conductor to interconnect electrodes that are part of the >grounding electrode system." Copyright 2002 National Fire Protection >Association
I hope you're not contending that metal underground water piping is permitted to be the *sole* grounding electrode...
>Now who is it that needs to educate themselves?
Geez, *another* one with reading comprehension problems. I have never disputed that metal underground water piping is required to be part of the grounding electrode system.
The whole argument is over *why*.
-- Regards, Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
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