My Argument with Iwire

[mivey]

Mike Whitt makes sense...

IMO, Crossman gary's follow-up post:

You say the two feet above ground
.
.
.
Read the book.

makes more sense.

 

[crossman gary]

The fix seems pretty easy to me. Each of the subsections in 250.52 need to be slightly reworded to establish what is the electrode and what is not. Once this was established, all of the rest of the arguments would go away.

For example...

in A1... a metal underground water pipe in direct contact with the earth for not less than 10 feet, and including not more than the first 5 feet of the aboveground portion from the point of entrance into the building.

That's pretty rough, but hopefully everyone understands what I mean.

in A2... okay as is

A3... change the wording to include a rebar stub-up as part of the electrode, and that the stub-up can be no longer than 12"

A4... not really an issue as the GEC is typically going to attach directly to the ring, without any stub-up or such.

A5... I see this one as okay, but obviously it has been misread before. Perhaps establish more clearly that the entire rod is the electrode, even the part aboveground. As in a previous post, I feel this is already done by the current wording. Still, being even moreclear would be good.

The rest are okay.

By giving a firmer explanation of what is the electrode and what isn't, all of the semantic and rhetorical arguments would be solved.

So.... CMP5.... please solve this issue by establishing that the rebar stub-up is part of the electrode, just as is done for building steel.

 

[iwire]

So.... CMP5.... please solve this issue by establishing that the rebar stub-up is part of the electrode, just as is done for building steel.

OK so now that we have it all fixed let me throw this wrench into things.:grin:

The following is just my opinion.

To me one of the greatest benefits of a CEE is it's durability. To that end having a section of 1/2" diameter bare steel exposed to the weather and / or soil conditions as part of the CEE continuity is a weak link.

Some areas turn the steel up inside protected areas so I guess thats OK but other areas just stub out the rebar in an area that will later be backfilled with soil. In my area soil conditions will rot bare steel fairly quickly. This would go unseen and really not 'fixable'.

IMO if they are going to say that a rebar stub is acceptable it should be with the condition it is either in a dry location or protected from corrosion.

Best case they would say no you can not use a rebar stub out, we must use a copper conductor as either the entire electrode or the 4 AWG needs to be connected to the rebar inside the pour.

Rant off ...... thanks for listening.:smile:

 

[crossman gary]

I hear you Bob.

I certainly would not disagree with a decision that the stub-up had to be made with a material that did not rust or corrode. Maybe stainless steel, or brass, whatever, even galvanized steel rebar?

Maybe these could be manufactured and listed as specifically for the application? And that plain ol' ordinary rebar would not be used for this?

What about a stub-up made from a ground rod with the ground attached to the rebar system? Bend it in a 90 degree angle and then tie it to the rebar on a horizontal rebar run, with the vertical part of the gorund rod stubbing up through the concrete? Yea, that would probably violate the listing/instructions of the ground rod.

To me, the CEE is a really important part of the grounding electrode system, so if we can make sure the rebar stub does not rust off in 2 years, then that is obviously a good thing.

 

[crossman gary]

Oh, and Bob....

I guess my point in my CMP5 post was that if they are going to allow the rebar stub as an attachment point, then they may as well go ahead and call it part of the electrode. Because that is in fact what it is if they allow the stub-up.... cuz it certainly is not a GEC.

 

[George Stolz]

Care to explain what you differ with?

Sure, the text literally states that we can't connect outside of five feet. There is no literal permission to connect between zero and five feet.

Prior to the five foot mandate introduced somewhere around 1986, the water pipe electrode was connected to outside of soil (outside of the area described in the definition of the electrode), and no one thought anything of it. Now, people point to the restriction as proof that we can. What proof did installers have in 1980?

That same proof then is what installers have now for the CEE.

I'll yield to George at the moment. If he doesn't want to attack it, I may myself.

Knock yourself out, I've had this argument before and it didn't really change anyone's mind, that I can recall. :smile:

 

[jwelectric]

You say the two feet above ground is not part of the electrode.

I say you are misinterpreting what the code says about it.

It is okay to disagree with me

Notice the term "though which" in the definition. This does not say that "only the portion in contact with earth" can be an electrode. To make that determination, you must go to 250.52 and look at each electrode type individually.

Yes I do see that ?through which? part and I also see the part that says ?a direct connection to earth is established.? The two feet above earth is in no way in direct contact with earth. To say that the two feet above ground is the ?through which? would not the grounding electrode conductor also be the ?through which? also thereby making it an electrode.

For example, the entire metal frame of the building which meets the criteria in 250.52(A)(2) is an electrode. Yep, even the part on the 2nd floor. The building steel on the 2nd floor is part of the electrode as described in the section.

That the building frame parts which are not in contact with the earth are still considered by the NEC as the electrode, yes, on the 2nd floor, just look at 250.52(A)(2)(3). None of the building frame is even touching earth, yet it is considered as an electrode.

and we know this simply because the book says so. I haven?t heard any argument about the steel of a building.

Notice On the entire length of the rod being the electrode rather than just the portion below ground:

First, the definition - the entire rod is a conductive object THROUGH WHICH a direct connection to earth is made. The part of the rod above ground and the interior of the rod is the "through which" part. The very outside layer of atoms of the rod is the part that establishes the direct connection to earth.

Again using this logic the entire length of wire supplying the electrode is part of the conducting path therefore you are saying that we don?t have a GEC as it is electrode also.

Notice Second, 250.52(A)(5) - doesn't say that only the part that is contacting earth is the electrode. It infers that the entire pipe or rod is the electrode.

Nowhere does the NEC infer anything. It is mostly cut and dry. On the part concerning grounding electrodes each section that address them clearly states that part that is in direct contact or underground is electrode and any part that isn?t is not part of the electrode. (remember we are addressing three of the electrodes, metal water pipe, rebar and driven electrodes)

Notice Third, 250.53(G) - "The electrode shall be installed such that at least 8 feet is in contact with the soil." This infers/establishes that electrodes longer than 8 feet exist, but if you have a longer rod, for example, 10 feet, then you only have to drive it 8 feet.

I don?t think that anything is inferred I think it makes a clear statement. The rod is required to have 8 feet in contact with mother earth and it is this eight feet that constitutes the electrode. Anything above mother earth is just a rod sticking out of the ground for a wire to be attached to just like the bus bar allowed in 250.64.

Notice and read the last sentence of 250.53(G) - "The upper end of the electrode shall be flush with or below ground level unless the aboveground end and the GEC conductor attachment are protected against physical damage.

That last one positively says that if part of the rod is aboveground, it is still an electrode.

The sections definitely refer to the entire length of the rod being an electrode, not just the underground part.

Not unless you are reading something different that what I am reading. Did you not say that the rod was required to be eight foot long? If eight feet is in the ground then the requirement for the electrode is satisfied and anything sticking out of the ground is nothing more than rod.

Notice On the the waterpipe and the portion just inside the building... I'll yield to George at the moment. If he doesn't want to attack it, I may myself.

I welcome any and all comments. I have the code section right here in front of me so I am prepared.

Notice Point is, you can't just use "sense" to determine what the code "says". You actually have to read the various sections and put in the effort to figure out what it literally says. Just because some of us "prefer" it to say something, or just because "it makes sense like that," or just because "I have always done it like that," is not good enough.

I could not agree more with this statement. I also know from experience that once someone steps out of the box it is easy to see that the walls they have been looking at for so long have another and completely different view.

Notice Read the book.

There are several people on this site that will attest that on average I will spend more time in the NEC in one day than most will in a year. I see and talk with those responsible for writing the NEC more often than some in here see their families.
Now just what part do you want me to read?

Iwire, your comment about 250.30 and a metal water pipe would fit into the exception found in 250.52(A)(1) as outlined in 250.30(A)(7)(1)
Over the years in older buildings I have found transformers that were bonded to metal water pipes that had been repaired with nonmetallic pipes thereby eliminating the electrode. I also think this needs to be addressed but has been shot down in the past.

 

[Pierre C Belarge]

I have not read all 100+ posts, but I am getting the gist of this thread.

This thread is a perfect example of what I see and hear in different sites and the field. Different people read/understand the NEC differently than others. Part in case due to the said person's local upbringing in the industry, and part due to the reading skill levels different people have-and the areas of the NEC that are not well written. The different styles of the written word, due to the age of the section (some have been in the NEC for many years/cycles), and the fact that so many different people have written/contributed to the NEC.

1. I understand that the NEC is not a design manual or "know-how" document.
2. I also understand that of the last number of years, due to many reasons, there are more people who are students of the NEC and the level of scrutiny has become intense.
3. The industry has grown in complexity and size, with technology progressing much faster than the changes in the NEC, which itself presents some issues of compliance/installation for the installer/inspector.

Now, this is all leading to the fact that the installer and others (such as engineers) in the industry are finding it much more necessary to look to manufacturers and other industry experts, such as Underwriter Laboratories, to help decide what will and will not be acceptable. This puts tremendous pressure on the ECs who are installing installations that fall into this category of work.


We can all discuss this on a site like this, which will definitely help in sharpening our code skills, but these discussions do not necessarily relieve the pressure of the EC as I see it in the field.

It would be helpful (although I am not sure how to reach this end), to have a group of "outside industry people" helping to develop/rewrite some portions of the NEC that really need the changes made to help bring the NEC into the 21st century/scrutiny it is receiving today.

As the process is set up today, I think too much pressure, in too short a time period, is being directed to the CMP/NFPA to produce a document every 3 years that is sufficient to meet the needs of our industry.

BTW: from what I have read, this is a good thread. :grin:

 

[jwelectric]

Sure, the text literally states that we can't connect outside of five feet. There is no literal permission to connect between zero and five feet.

Prior to the five foot mandate introduced somewhere around 1986, the water pipe electrode was connected to outside of soil (outside of the area described in the definition of the electrode), and no one thought anything of it. Now, people point to the restriction as proof that we can. What proof did installers have in 1980?

That same proof then is what installers have now for the CEE.

Back in the 70s a metal water pipe was required to be made electrically continuous but this rule was taken out of the NEC during the 80s


1975 code cycle

1984 code cycle

In the 1993 code cycle verbiage of the five feet of interior water pipe was introduced and in this code cycle these five feet was referred to as a conductor. (forgive the color to the attached photo)

In every code cycle that I have a copy of it is very clear that in order to qualify as an electrode the metal water pipe has to meet two criteria. One it must be underground and two it had to be at least 10 feet long underground.

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 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.
(End of sentence concerning the electrode)

(beginning of new sentence addressing part of the electrode SYSTEM which would include the conductor as this sentence points out)
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.

As clearly pointed out in the 1993 cycle the five feet of interior water pipe is only a point to land the grounding electrode conductor or bonding jumpers to and does not meet the underground in contact with earth that the is required of the electrode. It even makes the statement that the five feet on the inside is conductor not electrode.

I also understand that some will stand pat on the fact that the five feet of metal water pipe on the inside is part of the same pipe that is underground but they must understand that in the first sentence it makes it very clear that the electrode must be underground.

I have metal well casing that is more than 10 feet in earth. I run a conductor from this metal water casing along the same ditch as the nonmetallic water pipe that is supplying the building and attach this conductor to a piece of metal water pipe located within the first five feet of the building. From this metal water pipe I install a bonding jumper to ground rods installed outside. Does this installation comply with today?s NEC?
If so is the five feet of metal water pipe that is connected to the nonmetallic water pipe between it and the well now become an electrode.

 

[LarryFine]

If so is the five feet of metal water pipe that is connected to the nonmetallic water pipe between it and the well now become an electrode.

It sounds like a conductor to me.

 

[mivey]

It sounds like a conductor to me.

It did call it a conductor. I was thinking it was more like part of the connection.

 

[George Stolz]

Thanks for the correction about the dates, Mike. I'm at a disadvantage, I don't have any old code books.

I was just going off of memory, as far as what I had been told (in a previous thread on this from Pierre) about when the five-foot rule came into play, I remembered '83 when it should have been '93.

In the 1993 code cycle verbiage of the five feet of interior water pipe was introduced and in this code cycle these five feet was referred to as a conductor.

In that edition, was it required to run GECs unbroken to the GEs?

For example, in the 2008 edition we are required to make the GEC continuous (250.64(C)) from the service to the grounding busbar, or from the service to the grounding electrodes (250.64(F)). Was it the same in 1993?

The reason I ask is because if the same basic rules were in place then, then we would not have been able to use that five feet anyway.

As it stands, if one were to adopt the philosophy that we can only connect directly to the business portion of a grounding electrode, the five foot restriction means nothing, because we can't connect there anyway without specific permission. In for a penny, in for a pound.

 

[ItsHot]

what?

what?

What is this thread about? :-?

 

[George Stolz]

"Can you connect to a Ufer by stubbing up a piece of rebar out of the foundation and connecting your Grounding Electrode Conductor to it?"

 

[Pierre C Belarge]

"Can you connect to a Ufer by stubbing up a piece of rebar out of the foundation and connecting your Grounding Electrode Conductor to it?"

As I mentioned, I did not read all of the posts in this thread.

Based on your above post, I am one who says no, one cannot us the stub of the rebar sticking up out of the footing for connection of the GEC.

 

[jwelectric]

Thanks for the correction about the dates, Mike. I'm at a disadvantage, I don't have any old code books.

I was just going off of memory, as far as what I had been told (in a previous thread on this from Pierre) about when the five-foot rule came into play, I remembered '83 when it should have been '93.


In that edition, was it required to run GECs unbroken to the GEs?

No. This requirement in last sentence of 250-91(a) was for it to be continuous but not to the electrode

For example, in the 2008 edition we are required to make the GEC continuous (250.64(C)) from the service to the grounding busbar, or from the service to the grounding electrodes (250.64(F)). Was it the same in 1993?

There is no requiremenr now or then for the GEC to be continuous from the grounded conductor to the electrode.
250.64(C) only requires the GEC to be continuous from one end to the other. It has no requirement at all as to where the two ends are to land.

(C) Continuous. Grounding electrode conductor(s) shall be installed in one continuous length without a splice or joint except as permitted in (1) and (2):

(1) Splicing shall be permitted only by irreversible compression-type connectors listed as grounding and bonding equipment or by the exothermic welding process.
(2) Sections of busbars shall be permitted to be connected together to form a grounding electrode conductor.

What was it someone else had to say earlier in this thread?

Point is, you can't just use "sense" to determine what the code "says". You actually have to read the various sections and put in the effort to figure out what it literally says. Just because some of us "prefer" it to say something, or just because "it makes sense like that," or just because "I have always done it like that," is not good enough.

The whole of 250.64 is addressing the installation of the Grounding Electrode Conductor. I don?t see anything that tells me how to hit the grounding electrode. For this information I need to read just a little more of the NEC down in 250.68.

Here we are told that the connection to the grounding electrode is required to be accessible. Exception 1 relieves this requirement for CEE, driven or buried electrodes. The metal water pipe is not mentioned in this exception therefore the connection to the metal water electrode is still required to be accessible.
250.52(A)(1) allows the first five feet of interior metal water pipes to be included in the grounding electrode system.
250.68(B) says that should these five feet are used for the grounding path to the electrode or that part that has 10 feet or more underground then bonding jumpers must be installed around any thing that breaks or could interrupt this path and they must be long enough to allow the removal of anything that might get removed.

The reason I ask is because if the same basic rules were in place then, then we would not have been able to use that five feet anyway.

As it stands, if one were to adopt the philosophy that we can only connect directly to the business portion of a grounding electrode, the five foot restriction means nothing, because we can't connect there anyway without specific permission. In for a penny, in for a pound.

I can?t find any requirement to land directly to the electrode. I see many different allowances to land anywhere on the grounding electrode system even the extra two feet of a 10 foot ground rod. This allowance is given along with the allowance to use aluminum grounding electrode conductors as long as it is at least 18 inches from contact with earth. Eight feet in direct contact with earth is the electrode and the two feet above earth is what ensures an uninterrupted path to that electrode as required by 250.68 which mandates the connection of grounding electrode conductors and bonding jumpers that connect the electrodes together.

On a building that has more than one service disconnect I can install one grounding electrode conductor and install bonding jumpers to the grounded service neutrals again the grounding electrode conductor is not continuous from neutral to electrode, 250.64(D)(1). On this same building each disconnect can have its own grounding electrode conductor installed from the neutral in the service disconnect to any point on the grounding electrode system and again it is not required to hit any electrode 250.64(D)(2).

Where does this thought that the grounding electrode conductor must land on both the grounded conductor in the service disconnect and the grounding electrode without splice of joint come from? The only requirement is that there is no reversible splice in the grounding electrode conductor between connection and connection to be found in 250.64.

It might be that no one has though to look up the definition of a grounding electrode conductor and don?t yet even know what it is.
Grounding Electrode Conductor. A conductor used to connect the system grounded conductor or the equipment to a grounding electrode or to a point on the grounding electrode system.
I think that the first five feet of a metal water pipe on the interior of a building is allowed to be part of the grounding electrode system as outlined in 250.52(A)(1) to which the grounding electrode conductor is allowed to land. The other end can hit the neutral at the service head if one so desired, 250.24(A)(1).

The supplementary electrode for a metal water pipe electrode required by 250.53(D)(2) don?t have to hit either an electrode nor the grounded conductor. It can come from the supplementary electrode to the meter can again not hitting the neutral.

Here is one to think about for a while. I have all eight electrodes as described in 250.52 on this site. I install a conductor from each of these eight electrodes to a central accessible location and bring a grounding electrode conductor to this same location. I then connect all these conductors together using an exothermic welding process. Would this be compliant? :wink:

 

[Pierre C Belarge]

Also, check out 250.24(A)(4).

 

[jwelectric]

Post before and didn't know I did

 

[George Stolz]

It's been a while since I've argued with the pitbull, I'm still game.

For example, in the 2008 edition we are required to make the GEC continuous (250.64(C)) from the service to the grounding busbar, or from the service to the grounding electrodes (250.64(F)). Was it the same in 1993?

There is no requiremenr now or then for the GEC to be continuous from the grounded conductor to the electrode.
250.64(C) only requires the GEC to be continuous from one end to the other.

And then 250.64(F) states that it's supposed to start in the service equipment, and end in either a grounding electrode busbar or at a grounding electrode, like I said.

It has no requirement at all as to where the two ends are to land.

Just so you don't miss it again, I'm repeating it: 250.64(F).

... 250.68.

Here we are told that the connection to the grounding electrode is required to be accessible. Exception 1 relieves this requirement for CEE, driven or buried electrodes. The metal water pipe is not mentioned in this exception therefore the connection to the metal water electrode is still required to be accessible.

No, it's not required to be accessible if the connection is buried. It's a buried electrode.

250.52(A)(1) allows the first five feet of interior metal water pipes to be included in the grounding electrode system.

Read the words, Mike. It does not. It places a prohibition on farther than five feet, it does not permit us to use zero to five feet.

Does 310.4 prohibit parallel conductors under 1/0? No. This is the same.

250.68(B) says that should these five feet are used...

It doesn't mention that five feet at all, Mike. It can be applied to the entire installation of the grounding electrode.

I see many different allowances to land anywhere on the grounding electrode system even the extra two feet of a 10 foot ground rod.

I fail to find specific permission to connect to the extra 2' of a ground rod. If you believe this to be assumed, you're halfway to my way of thinking already.

The "business portion of an electrode doctrine" should not have any allowances in it. If I can't connect to rebar stubbed up out of concrete, then I can't connect to a water pipe stubbed up out of earth, and I sure can't connect to a ground rod stubbed up out of the earth either. To believe a Ufer is different than any of the others would be hypocritical.

On a building that has more than one service disconnect I can install one grounding electrode conductor and install bonding jumpers to the grounded service neutrals again the grounding electrode conductor is not continuous from neutral to electrode, 250.64(D)(1).

A wire connected to another wire by using a means that fuses the pair of wires together to become one wire. Hmm...

On this same building each disconnect can have its own grounding electrode conductor installed from the neutral in the service disconnect to any point on the grounding electrode system and again it is not required to hit any electrode 250.64(D)(2).

Any point on the system comprised exclusively of grounding electrodes and grounding electrode conductors. I don't see "A conductor used to connect the system grounded conductor or the equipment to a grounding electrode or to a point on the grounding electrode system, or an indescriminately selected chunk of something connected in some proximate means to one of the two."

 

[jwelectric]

There is no requiremenr now or then for the GEC to be continuous from the grounded conductor to the electrode.

250.64(C) only requires the GEC to be continuous from one end to the other. It has no requirement at all as to where the two ends are to land.

And then 250.64(F) states that it's supposed to start in the service equipment, and end in either a grounding electrode busbar or at a grounding electrode, like I said.
Just so you don't miss it again, I'm repeating it: 250.64(F).

Okay let?s look and see where it gives instruction on how to terminate this ground electrode conductor in 250.64.

250.64 Grounding Electrode Conductor Installation.
Grounding electrode conductors at the service, at each building or structure where supplied by a feeder(s) or branch circuit(s), or at a separately derived system shall be installed as specified in 250.64(A) through (F).
(F) Installation to Electrode(s). Grounding electrode conductor(s) and bonding jumpers interconnecting grounding electrodes shall be installed in accordance with (1), (2), or (3). The grounding electrode conductor shall be sized for the largest grounding electrode conductor required among all the electrodes connected to it.
(1) The grounding electrode conductor shall be permitted to be run to any convenient grounding electrode available in the grounding electrode system where the other electrode(s), if any, are connected by bonding jumpers per 250.53(C).
(2) Grounding electrode conductor(s) shall be permitted to be run to one or more grounding electrode(s) individually.
(3) Bonding jumper(s) from grounding electrode(s) shall be permitted to be connected to an aluminum or copper busbar not less than 6 mm ? 50 mm (? in. ? 2 in.). The busbar shall be securely fastened and shall be installed in an accessible location. Connections shall be made by a listed connector or by the exothermic welding process. The grounding electrode conductor shall be permitted to be run to the busbar. Where aluminum busbars are used, the installation shall comply with 250.64(A).

Well I have read it till I can recite it and I still can not find how to terminate this grounding electrode conductor on the electrode.
I get it now, it is not covered here so it must be covered elsewhere in the NEC.

Oh yea here I found it.

250.68 Grounding Electrode Conductor and Bonding Jumper Connection to Grounding Electrodes.
The connection of a grounding electrode conductor at the service, at each building or structure where supplied by a feeder(s) or branch circuit(s), or at a separately derived system and associated bonding jumper(s) shall be made as specified 250.68(A) and (B).
Accessibility. All mechanical elements used to terminate a grounding electrode conductor or bonding jumper to a grounding electrode shall be accessible.

Exception No. 1: An encased or buried connection to a concrete-encased, driven, or buried grounding electrode shall not be required to be accessible.

Exception No. 2: Exothermic or irreversible compression connections used at terminations, together with the mechanical means used to attach such terminations to fireproofed structural metal whether or not the mechanical means is reversible, shall not be required to be accessible.

Effective Grounding Path. The connection of a grounding electrode conductor or bonding jumper to a grounding electrode shall be made in a manner that will ensure an effective grounding path. Where necessary to ensure the grounding path for a metal piping system used as a grounding electrode, bonding shall be provided around insulated joints and around any equipment likely to be disconnected for repairs or replacement. Bonding jumpers shall be of sufficient length to permit removal of such equipment while retaining the integrity of the grounding path.


Couple this with the second sentence of 250.52(A)(1) which makes the statement that the five feet of interior pipe is part of the electrode system and that alone should be more than enough to clear the air that it is not electrode.

If this is not enough then tell me what constitutes a grounding electrode. The NEC defines it as:
Grounding Electrode. A conducting object through which a direct connection to earth is established.
The five feet of metal pipe hanging from the floor joist is in no way in direct connection with earth therefore not electrode.

250.52(A)(1) allows the first five feet of interior metal water pipes to be included in the grounding electrode system.

Read the words, Mike. It does not. It places a prohibition on farther than five feet, it does not permit us to use zero to five feet.

It also does not require anyone to use the first five feet as anything either but it does refer in that same sentence as this five feet being part of the grounding electrode system and does not just say grounding electrode. Wonder why they found it necessary to use the word system instead of calling a grounding electrode?

250.68(B) says that should these five feet are used...

It doesn't mention that five feet at all, Mike. It can be applied to the entire installation of the grounding electrode.

Yes you are right is doesn?t say anything about the five feet but it does address the path that current would travel from the GEC through the five feet of pipe to the electrode that is required to be in direct contact with earth or in other words that part of the metal water pipe that is underground not swinging from a 2 by.