What is NEC Code For This Grounding Scheme ?

[gfretwell]

You can run one EGC to several boxes and it can be a long bus, a star configuration or any combination. You only have to be sure the ground wire is big enough to serve the biggest circuit you are dealing with and that it is protected from physical damage.

I would not get to worried about ground loops and such in a residential equipment grounding system.. It is mostly hype anyway. We fixed most surge problems by adding more bonding, possibly creating loops and never fixed anything by getting anal with "star grounding". (based on 20 years of computer and lightning protection experience in SW Florida)

[gfretwell]

One way you can accopmplish this would be to run a 12-2/wg to the new dedicated computer circuit, put a J box in this circuit in the crawlspace and tap off that 12ga grounding conductor to ground any other 15 or 20a circuit you want.

[w_tom]

The purpose of a green safety ground wire is to connect fault electricity to the ground bus bar inside breaker box. Electric faults must connect back to breaker box to trip a circuit breaker - for human safety.

Pipes must never be a carrier of electricity - an attitude change from many decades ago. That cold water pipe ground clamp is to remove electricity from water pipes; not to dump electricity into water pipes. Its primary function is human safety.

Your earth ground is those rod electrodes that are nearby the breaker box and dedicated only for earthing. BTW, those rods should be separated eight feet or more (not six feet). They bond the breaker box, short, to earth ground.

That safety ground wire to water pipe must be less than 5 feet from where pipe enters the building. This for numerous reasons including to pickup any stray currents that might enter from outside via city water.

Some jurisdictions also want a steel bathtub bonded by a dedicated 6 AWG ground wire to breaker box safety ground. Again, a connection for same reason - to remove electricity from plumbing. Plumbing must not carry electricity.

General concepts for safety grounding are summarized by volts500 in alt.home.repair entitled "Grounding Rod Info" on 12 July 2003 at

includes good safety tips such as hot water heater and meter ground shunts.

[RBM]

Your grounding electrode system is those driven rods, 10 feet or more buried metallic water pipe, well casing and any of a number of other types of electrodes

NEC 250.53B Ground rod spacing minimum 6 feet apart, albeit 8 feet would probably be better

[bud--]

Its the village idiot back again with his nonsense about water pipes.

Buried metal water service pipe at least 10 ft length has been

*required* to be used as a grounding electrode since 1777.

Grounding wires, that the OP is interested in, can connect in the first

5 feet of water pipe if the pipe is used as a grounding electrode.

?Remove electricity from water pipes? is technical illiteracy.

If the pipe is only being ?bonded? (not used as an earthing electrode) the connection does not have to be within 5 feet of the entrance. It is not used as an earthing electrode only when less than 10 ft buried metal.

More technical illiteracy.

Name one.

-- bud--

[John Ross]

If it is connected at the first five feet and there is the all metal water pipe, would it serve as BOTH a bonding and and additional "ground"?

In my case the house already uses the water pipe as the only ground. So if a ground rod was installed and then "bonded" to the pipe, wouldn't the pipe still act as sorta a second ground anyway (like having 2 ground rods, maybe)?

As far as your comment about it would be ok to just attach the ground wire to the first five feet of the pipe to ground the outlet, doesn't that contradict what you previously have said about that would not trip the breaker and wanted me to make sure the wire went back to the panel?

thanks,

-- John

[RBM]

John, the thing you're not getting is that it's a grounding electrode system. Everything that is part of it is connected together and becomes one. If your outlet ground was connected to the panel or the water pipe (first 5 feet) or a ground rod, it's all the same, as they are interconnected

[bud--]

If a water pipe is used as a grounding electrode, it is "bonded" in the process.

As RBM said, the grounding electrodes form a system. Your water pipe and the added ground rod are *both* grounding electrodes for your electrical service. You could have more electrodes. Your added ground wires to receptacles can be connected anywhere in that *system*. That includes the service panel ground bar, the first 5 feet of the water pipe and the heavy connecting wires to the water pipe and ground rod.

An added ground rod can be connected anywhere in the present water pipe grounding electrode system (but there are rules). An added ground rod would probably not be connected to the first 5 feet of water pipe (but it could be) - there are usually better places to make the connection.

I would usually make added connections to the heavy connecting wires using a split bolt (also known as a karnie).

I believe I said there has to be a *metal* path back to the panel.

What is not allowed is using the earth as part of the path - like connecting your added ground wires only to a ground rod with no additional metal path to the electrical service. I questioned using a ground rod as "insurance" for a metal path because a ground rod (with earth path) provides very bad "insurance".

[w_tom]

The heart of a human safety ground system is a bus bar inside that breaker box. Everything it grounds (bonds to) must connect directly to that bus bar by approved materials. For example, you cannot connect a wall receptacle to an earth ground or water pipe. Neither earth nor pipe to is approved to make that connection. Code says there must be a direct wire connection from wall receptacle grounds to breaker box safety ground. Each ground for each circuit must connect directly back to the breaker box safety ground. Each wire that earths that bus bar also must connect directly back to the breaker box. Code even defines which conductors can only make that connection.

Connecting a ground rod to breaker box via any pipes is not valid. The ground rod will better earth a water pipe. But from the perspective of a breaker box, that is still only a water pipe connection - no longer sufficient for earthing.

Irrelevant is whether your water pipe does or does not create an earth ground. Your breaker box must be earthed by some other earthing electrode with its own dedicated connection - regardless of whether a water pipe ground does or does not exist.

Code is quite blunt about it. The code lists electrodes that are sufficient for a breaker box earth ground. Cold water pipe is no longer on that list. The water pipe is only an earth ground that can be an 'also' earth ground. Water pipe earth ground is no longer sufficient. Code lists other electrodes that must make ant earth ground. List includes the dedicated ground rod, a large earthing plate, or an Ufer ground. Each must make a dedicated connection to breaker box safety ground using listed conductors. Pipes, which are installed for other (non-electrical) purposes, are no longer sufficient for earthing.

Take everything Bud posts with a grain of salt. Truth is not a strong suite with salesmen - especially those who only learn from salesmen classes. What jurisdictions now required steel bathtubs bonded to breaker box safety ground? Many including mine. If Bud had any experience, he would know that. But the point of that example: pipes are not longer sufficient for bonding or earthing anything. Pipes bonding a steel bathtub, in some jurisdictions, are no longer considered sufficient for human safety. If a pipe is being used for earthing, one must still install another earthing electrode as if the pipe did not even exist.

It does not matter if a metal connection exists. Conductor that connects an earthing electrode to that bus bar inside a breaker box must be 'listed' - approved for making a connection. Totally irrelevant is whether a connection is metal. It must be even better. It must be approved for making that connection.

Even if bonding an earth ground rod to a water pipe, to the breaker box, that is only a water pipe earth ground. To meet post 1990 code requirements, that earth ground rod must be bonded directly to the breaker box via 6 AWG bare copper wire. Water pipes are no long acceptable as a connecting device. When bonding an earth ground rod via water pipes, then you are using pipes as a conductor. Water pipes are no longer sufficient for earthing AND are not approved for making that electrical connection.

[RBM]

I never saw such a pile of cockamamie nonsense in my life. Instead of dreaming this stuff up, Please direct us to the locations in the NEC where we can find this "information"

[w_tom]

Instead of posting denials, instead, ask about the sentences you do not understand.

Meanwhile, if you think pipes are acceptable as electrical conductors, then don't bother. If you don't even know that basic concept, then ignorance will not even be justified by a reply.

[RBM]

Virtually everything you wrote is baseless incoherent gibberish, otherwise you'd be able to produce some NEC documentation to back it up

[M Q]

Gee. NEC seems to think that water pipes are permitted as Grounding electrodes. Section 250.52(A) Electrodes Permitted for Grounding. subsection (1) "Metal Underground Wter Pipe" Go read it if you can.

[John Ross]

I think one thing that throws me off is that when they built these houses, they just connected to the nearest water pipe to the panel (which is on the opposite side of house where water pipe enters). I had an electrician come out and told me he would drive a ground rod and just leave the pipe bond alone (since it is "already connected"). I asked about the 5 foot thing and as EVERY electrician in this town I have talked to, get a blank look or a "I never heard of that." You can see why I am going crazy.

But back to your comment about the "grounding electrode system." I thought that 5 foot rule was because of people replacing pipes with plastic. OK, so that makes sense if you look at it as a ground to earth. In other words, if someone adds a plastic pipe past the 5 foot, you now have the earth ground, but I thought the idea of "bonding" pipes was to (also) protect the pipes from becoming energized if a hot wire touches one. So wouldn't you want a requirement to have it bonded to other parts beyond the 5 foot also?

Another thing: Not one electrician has told me anything about 2 ground rods; they just say one. Is that a requirement, or just something you think is better?

Thanks for the patience :) It seems my city doesn't have one competent electrician!

-- John

[John Ross]

Yes, I remember that was the guy who wanted to just put a ground rod in and connect it to the water pipe. I think that is when you got into different resistances(?) and might not go back to the panel and thus not trip breaker. So if the new ground rod IS connected to the panel, and the water pipe still serves as a ground, then you are saying that is not a concern as far as tripping breaker if added ground wire is connected at any point? I guess I got mixed up, but I thought you were saying that the ground rod had more resistance than the water pipe. So am I correct in that you were just concerned about that if the ground rod was not connected to the panel?

That would clear up some confusion, because I was thinking you were saying that adding the ground rod might actually give an inferior ground that what I already have.

Thanks for your patience also :) I wish you or RBM could come out and do the job!

-- John

[bud--]

Not only permitted - they are *required* to be used as electrodes.

w_ uses google-groups to find "grounding" so he can post his bullcrap. He gets corrected regularly on this newsgroup, but it doesn't matter. You can't argue with a Jehovah's witness.

[w_tom]

Apparently, you are talking about connecting a ground rod to a 6 AWG wire that also connects to water pipe. But that is not what you posted. You posted bonding a ground rod directly to water pipe which is not acceptable.

That '5 foot' requirement is for numerous reasons. One is due to currents existing outside the building. A water pipe entering the building must be bonded to the breaker box safety ground where those currents would enter the building. Those currents would only travel inside the builiding on less than 5 feet.

Better ground means no wire splices. Although not require by code, you want that earthing rod to be connected by a continuous 6 AWG wire

- no splices.

One ground rod is sufficient if its resistance measures less than 25 ohms. Many electricians don't even know how to measure that resistance. Code does not even define how to measure it. But certain soils are know to be sufficiently conductive. Therefore some electricians assume one ground rod is less than 25 ohms.

Other electricians don't even bother 'guessing'. Code says that if a second rod does not drop resistance below 25 ohms, then nothing more need be done. Therefore other electricians automatically install two rods, don't care what the earthing resistance is, and don't buy an expensive ground resistance measuring tool.

I am appauled that you would have Bud do any electrical work. He is a salesman - all about presentation and severely short on electrical knowledge. His knowledge comes only from reading books and taking seminars. He is a promoter - a snake oil salesman - has been exposed lying.

Not anything metal can be used as Bud posts. For example, not any split bolt can be used. Grounding must be only with a split bolt that is also listed (approved). Not any pipe or rod can be used. Those too must be listed. Of course, this is not a problem. Electrical supply houses only sell earth ground rods that are listed. The point is that everything in that connection from ground rod to breaker box safety ground must be approved for that function.

Connecting a ground rod to the water pipe - using the water pipe as a connection from ground rod to breaker box - violates code requirements for earthing. Whatever makes that connection must be 'listed' as a conductor. Water pipe is not approved as an electrical conductor. Only connection to a pipe is to remove electricity. Using pipes as an electrical conductor - dumping electricity into water pipes - is no longer permitted.

[pawlowsk002]

Folks:

w_tom is slipping. I keep throwing random refs to surge protectors into Usenet and private-forum posts, and he never comes in to reply. Such neglect.

Correct me if I am wrong, but there was a time when the NEC allowed one to ground equipment to a nearby water pipe. Of course, there was also a time (look at the 1899 code, which is posted online somewhere) when they allowed one to use a gas pipe as a grounding electrode. The time for either of those is not today.

Back when men were men and jackets were braided, one could safely assume that all pipes were metal. Metal pipes full of water from the ground to the might well provide a nice low-impedance path to ground. But we can't assume that now. My own house has all metal pipes. Were I to open up a 2nd floor wall, and install a ground clamp on a cold water pipe, and test the ground, it would probably be excellent. But then the wall is closed, the clamp forgotten.

Down the road, somebody replaces sections of the copper cold water pipes with plastic. Now I have a ground connected to a pipe, connected to nothing, and unless somebody tests the ground before and after plumbing, nobody is going to know about it. One day there is a direct short to ground. Fixtures have been replumbed with plastic supply connectors, except one old sink with separate hot and cold faucets. The cold faucet is now hot. The hot faucet is still bonded to ground at the water heater. Somebody turns one on, and reaches for the other...

In any case, a falsely advertised ground is bad enough; a ground that goes to unbonded metal is worse, and that's what grounding to a water pipe can get you. Sometimes I see washers or dryers that had been grounded to a nearby pipe. This isn't as bad in an unfinished basement; you can see all the pipe, but it's also the situation where putting in a run of grounded cable and a new receptacle is very easy.

Besides, if you're going to pull a single conductor into a space, you might as well pull in a cable, as somebody up there pointed out.

G P

[w_tom]

To perform electrical work, you are required to understand everything in Article 250.52. If using water pipe for earth ground, then any other electrode in Article 250.52(A) paragraphs two through seven also must be installed. Why? Water pipes are no longer sufficient for earthing. If using any other earthing electrode, then a water pipe earthing electrode is not required. BUT if using the water pipe for earthing, then the building remains insufficiently earthed according to Article 250.52. Another electrode must be installed.

"A metal underground water pipe shall be supplemented by an additional electrode .... " A building must also be earthed by structure frame, Ufer ground, ground ring (halo ground), or an earthing plate or rod. Water pipe is no longer sufficient for earthing. You are supposed to read everything; not read selectively. Keep reading. Article 205.52(D)(2). Article 250 then continues another 12 pages farther.

[bud--]

Your added ground wires can be connected at any point on the grounding electrode system. At any point there will be low resistance back to the ground bar in the service panel.

Yup.

Contrary to what the village idiot says, the resistance to earth of a pipe connected to a municipal metal water supply will be much lower than the resistance to earth of a ground rod.

Both are used to connect the *system* to earth so the system 'ground' is at about the same potential as the earth.

That is not what the ground rod was being used for in the original scheme.

Added to the existing system it improves the connection to earth. Your house could just use the water pipe when it was built (same with all the houses I have lived in). Because water service pipes in some locations were being replaced with plastic the code started requiring an additional electrode for new construction. Rods are the easiest to add. (The code now generally requires adding a "concrete encased electrode" for new construction.)

We're both probably available. Travel & expenses might be a little high.