AHJ Grounding Electrode Requirement

[Smart $]

The RCO (Residential Code of Ohio) does.

Dublin requiring a 200 AMP vs a 100 AMP service violates the below. IMHO. How is the public served by forcing a higher service rating?

...

So residential developments can impose building standards stricter than Code, but municipalities cannot?

Also, in your quote of RCO, you forgot to include...

102.2 Other laws.

The provisions of this code shall not be deemed to nullify any provisions of state or federal law. An approval by the board of building standards of any fixture, device, material, system, assembly or product of a manufacturing process, or method or manner of construction or installation shall constitute approval for their use anywhere in Ohio.

That's a biggie, as RCO cannot nullify ORC (state law).

 

[Rick Christopherson]

As pointed out earlier, at our voltages the GES is only there for lightning and surges (see 250.4(A)(1)) and three won't be much different than two

In my opinion, teaching that the grounding electrode is primarily for lightning protection is one of the greater disservices in Mike Holt's teachings. At the POCO level it certainly is one of the more significant functions, but at the end-user level, it is one of the lowest functions, not the primary function that (as I understand it) Mike teaches. If the primary purpose was lightning protection, you wouldn't need an 8' rod, and you certainly wouldn't need more than one of them.

Reread 250.4(A)(1) closer. It would appear that most people stop at the first term in the comma-list (lightning) and don't notice that it is just 1 of 4 listed purposes of the paragraph. Just because it is the first in the list, does not make it the most important, either.

Plumbers don't get electrocuted because the pipes are grounded. They get electrocuted when it isn't grounded (in whole or more importantly, in part). When metallic piping is in contact with building steel or enters the Earth, it is grounded and held to ground potential. As a matter of fact, if the lateral to the street is entirely metallic, it is a far lower resistance connection to Earth than several ground rods will ever be. As a low resistance conductor to Earth potential, Ohm's Law dictates that its entire length will remain at or near Earth potential within the limitations of its voltage drop.

A common problem is when a portion of the plumbing system becomes isolated from its Earth potential; either as the plumber is cutting it, or when someone installs plastic tubing somewhere in the system. When this happens, the isolated portion of the plumbing system can take on an elevated voltage due to capacitive/inductive coupling or direct contact with a current carrying conductor. The result is customers complaining of getting shocks in the tub or shower, or plumbers getting shocked while servicing the system. That's the same principle driving the requirement for equipotential grids around pools.

I think that one of the reasons why this can be confusing to some is because they primarily think of electricity as following "paths". Electricity doesn't care about where it came from or where it needs to get to. It only cares about differences in voltage. And when a difference in voltage exists, regardless of the cause, electrons will flow through conductive media.

 

[jxofaltrds]

So residential developments can impose building standards stricter than Code, but municipalities cannot?

Also, in your quote of RCO, you forgot to include...




That's a biggie, as RCO cannot nullify ORC (state law).

Didn't forget anything. Was just showing the 'economic' paret.

PS the RCO is in the ORC try Chapter 3781.

 

[suemarkp]

When metallic piping is in contact with building steel or enters the Earth, it is grounded and held to ground potential. As a matter of fact, if the lateral to the street is entirely metallic, it is a far lower resistance connection to Earth than several ground rods will ever be. As a low resistance conductor to Earth potential, Ohm's Law dictates that its entire length will remain at or near Earth potential within the limitations of its voltage drop.

The first and last sentences don't jibe because of the non-zero resistance of the earth. If you bury a long pipe in the earth and place a 120V conductor from a normal grounded utility feed on a stub of that pipe, there is going to be 120V on that pipe in the earth. At some point away from the pipe (guessing it will be at about a 4' diameter cylinder), the voltage will have been dragged down to zero. If you dig a hole around a short section of that buried pipe and sit your butt 2' from it and grab the pipe, you're going to get bit hard.

You are correct that failure to bond the pipe is a major problem and why most people get bit from a pipe. If you dig the same hole and grab the pipe from a non-faulted system, you still may feel a tingle if you're sitting in set earth and you have a lot of voltage drop in the neutral. Probably not lethal, but you'll feel a 9V to 12V shock when you're wet. A plumber probably doesn't care if there is 5V, 12V, or 120V on the pipe. If he can feel anything he's not going to be happy.

For 120V systems, I don't see how the earth really helps to "stabilize the voltage to earth" very effectively. Yes, it is a grounded conductor, but it is a conductor with high insertion loss, so it takes some distance before it has brought things down to the same level.

 

[Smart $]

Didn't forget anything. Was just showing the 'economic' paret.

PS the RCO is in the ORC try Chapter 3781.

The RCO itself isn't in ORC. It's adoption is covered... but that is not the same as it being in the ORC, which was brought up in the lawsuit.

 

[Rick Christopherson]

The first and last sentences don't jibe because of the non-zero resistance of the earth. If you bury a long pipe in the earth and place a 120V conductor from a normal grounded utility feed on a stub of that pipe, there is going to be 120V on that pipe in the earth. At some point away from the pipe (guessing it will be at about a 4' diameter cylinder), the voltage will have been dragged down to zero. If you dig a hole around a short section of that buried pipe and sit your butt 2' from it and grab the pipe, you're going to get bit hard.

You are correct that failure to bond the pipe is a major problem and why most people get bit from a pipe. If you dig the same hole and grab the pipe from a non-faulted system, you still may feel a tingle if you're sitting in set earth and you have a lot of voltage drop in the neutral. Probably not lethal, but you'll feel a 9V to 12V shock when you're wet. A plumber probably doesn't care if there is 5V, 12V, or 120V on the pipe. If he can feel anything he's not going to be happy.

For 120V systems, I don't see how the earth really helps to "stabilize the voltage to earth" very effectively. Yes, it is a grounded conductor, but it is a conductor with high insertion loss, so it takes some distance before it has brought things down to the same level.

I am not sure where you are going with this, so maybe you can clarify it some more.

It kind of sounds as though you think I am suggesting the Earthen-ground is supposed to do something about fault current. That is not what I said.

 

[jxofaltrds]

The RCO itself isn't in ORC. It's adoption is covered... but that is not the same as it being in the ORC, which was brought up in the lawsuit.

I an not able to debate the law. This is what was explained to me (us) back in June 2006 in a mandatory meeting. I guess the court said that this does not apply.

3781.10 Board of building standards - powers and duties.

(2) The rules governing nonresidential buildings are the lawful minimum requirements specified for those buildings and industrialized units, except that no rule other than as provided in division (C) of section 3781.108 of the Revised Code that specifies a higher requirement than is imposed by any section of the Revised Code is enforceable. The rules governing residential buildings are uniform requirements for residential buildings in any area with a building department certified to enforce the state residential building code. In no case shall any local code or regulation differ from the state residential building code unless that code or regulation addresses subject matter not addressed by the state residential building code or is adopted pursuant to section 3781.01 of the Revised Code.

Again no lawyer here but if it is adopted per 3781.01 that makes it a state law (IMHO).

 

[Smart $]

...
Again no lawyer here but if it is adopted per 3781.01 that makes it a state law (IMHO).

In essence, yes... but not exactly. Here's some snippets for you...

Laws are created by statutes that originate from legislative bills.

Regulations are standards adopted as rules.

...

Summary:
1. Legislation is a directive proposed by a legislative body while a regulation is a specific requirement within legislation.
2. Legislation is broader and more general while regulation is specific and details how legislation is enforced.
3. Legislation may be proposed by a head of state while regulations are simply enforcements by regulators and head of state doesn?t interfere.
4. Legislation is almost always internally generated within a country?s government while regulations may be internally or externally generated, especially pertaining to certain industry.

 

[don_resqcapt19]

...
Plumbers don't get electrocuted because the pipes are grounded. They get electrocuted when it isn't grounded (in whole or more importantly, in part). When metallic piping is in contact with building steel or enters the Earth, it is grounded and held to ground potential. As a matter of fact, if the lateral to the street is entirely metallic, it is a far lower resistance connection to Earth than several ground rods will ever be. As a low resistance conductor to Earth potential, Ohm's Law dictates that its entire length will remain at or near Earth potential within the limitations of its voltage drop.

In most cases the reason the plumber gets a shock is because the service neutral is compromised and the water pipe is acting as the neutral. When the pipe is cut the end that is connected to the building is an open neutral and will have line voltage on it.

A common problem is when a portion of the plumbing system becomes isolated from its Earth potential; either as the plumber is cutting it, or when someone installs plastic tubing somewhere in the system. When this happens, the isolated portion of the plumbing system can take on an elevated voltage due to capacitive/inductive coupling or direct contact with a current carrying conductor. The result is customers complaining of getting shocks in the tub or shower, or plumbers getting shocked while servicing the system. That's the same principle driving the requirement for equipotential grids around pools. ...

If there is direct contact between an ungrounded conductor and a plumbing pipe, a connection to earth will not make any difference. The only thing that will remove the voltage is a path back to the power source that will flow enough current to cause the OCPD to open. Connecting the energized pipe to earth will not remove the voltage from the pipe. It will energize a small area of earth around the pipe, but if you are touching the pipe and the earth a few feet away from the pipe you will still get a shock with a voltage that is close to that of the ungrounded conductor that has energized the pipe.
As far as the pool bonding, we are making sure that everything within touch is at the same voltage. We are not lowering the voltage of the pool equipment, the pool deck or the pool water. We are just making sure that all of these things are at the same voltage. We have to do this becuase the code rules require that we energize these items with a voltage that is equal to the primary and secondary grounded conductor voltage drop.

 

[Rick Christopherson]

Don, It would appear that both you and Mark (suemarkp) are discussing a topic that is completely different from what the OP is discussing and what I was discussing.

 

[Rick Christopherson]

Don, It would appear that both you and Mark (suemarkp) are discussing a topic that is completely different from what the OP is discussing and what I was discussing.

Maybe a little clarification is in order. Both you and Mark are discussing fault-conditions. No where in my discussions am I suggesting that a grounding electrode or water pipe are performing any special function during a fault condition. That is the purpose of the ground-to-neutral bond at the main, and it is that bond that clears a fault.

My discussion is regarding the purpose and function of the grounding electrode itself and also regarding the related topic of not tying the plumbing system (which is assumed to be earthen-grounded already) into the electrical grounding system.

 

[electricmanscott]

As the electrical inspector for my jurisdiction, I have always required the metal water pipe to be used as a grounding electrode, if available (Section 250.50). I have even gone a step further and required it to be terminated on the street side of the meter/shutoff valve; though I realize the code states it can be terminated up to (5) from metal water pipe point of entrance (Section 250.52(A)(1)).

The powers that be (my department supervisors) have asked me to stop requiring the use of the metal water piping as an electrode, due to possible electrocution of plumbers, etc, who may eventually work on the water lines with a potential stray current on the pipe.
Though I believe terminating the grounding electrode on the street side of the meter/shutoff will alleviate (not eliminate) the potential danger, I strongly believe I will lose this argument with my superiors and the metal water pipe electrode will no longer be required.

My question is since the lone ground rod would now be the only grounding electrode I could actually enforce by code, should I ask for a concession from my superiors that we require a triad grounding system, with 8' ground rods outside at the service lateral/service disconnect? As a former electrical contractor, I know that a single or even double ground rod system (Section 250.56) alone does not seem to provide an adequate grounding electrode system. I am strictly referring to service upgrades for existing structures. New homes or projects are always required to implement the concrete-encased electrode in the footing. Opinions welcome.

The second sentence here gives the impression that you enforce the code as you see fit, correct? That said it seems as though your superiors are doing that very same thing. In my state it would have to be statewide mandate through the proper channels and enacted into law.

Around here it is rare to see a cee in new resi construction. There is no qualifying rebar in the footings and the foundation is poured long before the EC has a chance to throw a peice of #4cu in. It's usually a couple of rods and done.

 

[hurk27]

Rick they were responding to the statement below which is just not true when the understanding of how connection to earth behave, now I will agree that the water pipe will have a much lower impedance then any rod or combinations of rods will ever have but the fact remains that with even this the pipe can never be depended upon reducing any voltage imposed upon the pipe to near Earth potential.
The quote below is in error as the earth can not do this because of the very little soil in close proximity of the pipe, the voltage drop will still be the greatest within the first shell around the pipe and this will always hold true as in the many test that has proved this.

Ohm's Law dictates that its entire length will remain at or near Earth potential within the limitations of its voltage drop.

The only way the water pipe could act as a safety is not because it is in contact with Earth but the fact that many times it connects to the next service down the road providing a low impedance path back to source.

Plumbers don't get electrocuted because the pipes are grounded. They get electrocuted when it isn't grounded (in whole or more importantly, in part). When metallic piping is in contact with building steel or enters the Earth, it is grounded and held to ground potential. As a matter of fact, if the lateral to the street is entirely metallic, it is a far lower resistance connection to Earth than several ground rods will ever be. As a low resistance conductor to Earth potential, Ohm's Law dictates that its entire length will remain at or near Earth potential within the limitations of its voltage drop.

 

[Rick Christopherson]

Rick they were responding to the statement below which is just not true ................

The quote below is in error as the earth can not do this because of the very little soil in close proximity of the pipe, the voltage drop will still be the greatest within the first shell around the pipe and this will always hold true as in the many test that has proved this.

As a low resistance conductor to Earth potential, Ohm's Law dictates that its entire length will remain at or near Earth potential within the limitations of its voltage drop.

No, my statement is not false. You need to read it very carefully. Ohm's Law will always prevail, and the voltage of any part of the system will depend on the amperage flowing across the resistive path, and that includes the resistive path of the soil or the copper conductor.

In addition to Mike Holt suggesting that the only purpose of a grounding electrode as lightning protection, too many people believe that the grounding system (as a whole) is only to clear fault current. That is not true. If that was true, then we could just replace the entire grounding system with a redundant neutral conductor (unfortunately, some people actually view the ground as exactly this).

The grounding system, as a whole, is far more complex in its purpose than many people pigeon-hole it into being. One of the purposes that gets overlook most often, is as a voltage reference. Without a grounding electrode, the secondary side of a transformer has the capability to float the entire system as high as the primary-voltage.

As it relates to the OP's discussion, the plumbing system is already grounded at earthen potential, and its actual voltage above earthen potential will be determined by the amount of current that is being sinked?, sunk? into the soil, and Ohm's Law regarding voltage drop.

So no, my statements were not incorrect. They just apparently haven't been read very carefully.

 

[jxofaltrds]

No, my statement is not false. You need to read it very carefully. Ohm's Law will always prevail, and the voltage of any part of the system will depend on the amperage flowing across the resistive path, and that includes the resistive path of the soil or the copper conductor.

In addition to Mike Holt suggesting that the only purpose of a grounding electrode as lightning protection, too many people believe that the grounding system (as a whole) is only to clear fault current. That is not true. If that was true, then we could just replace the entire grounding system with a redundant neutral conductor (unfortunately, some people actually view the ground as exactly this).

The grounding system, as a whole, is far more complex in its purpose than many people pigeon-hole it into being. One of the purposes that gets overlook most often, is as a voltage reference. Without a grounding electrode, the secondary side of a transformer has the capability to float the entire system as high as the primary-voltage.

As it relates to the OP's discussion, the plumbing system is already grounded at earthen potential, and its actual voltage above earthen potential will be determined by the amount of current that is being sinked?, sunk? into the soil, and Ohm's Law regarding voltage drop.

So no, my statements were not incorrect. They just apparently haven't been read very carefully.

NO. The OP had the plumbing isolated.

If I remember correctly he MADE them attach before the meter. Yes?

Could it be bonded? Yes. But most of us believe that you need to jumper the meter.

 

[Rick Christopherson]

NO. The OP had the plumbing isolated.

If I remember correctly he MADE them attach before the meter. Yes?

Could it be bonded? Yes. But most of us believe that you need to jumper the meter.

No, he did not have the plumbing isolated. If it's buried in the ground, then it is grounded at earthen potential, and that is not isolated. Jumping the meter is only a safeguard for continuity. In reality, the meter should be electrically contiguous by itself. (No, I am not dismissing the importance of this jumper.)

 

[don_resqcapt19]

...The grounding system, as a whole, is far more complex in its purpose than many people pigeon-hole it into being. One of the purposes that gets overlook most often, is as a voltage reference. Without a grounding electrode, the secondary side of a transformer has the capability to float the entire system as high as the primary-voltage.
...

There is no real current on the grounding electrode used to provide the voltage reference. The driven ground rod should be able to accomplish that function without using of the metal underground water pipe as a grounding electrode.

 

[Rick Christopherson]

There is no real current on the grounding electrode used to provide the voltage reference. The driven ground rod should be able to accomplish that function without using of the metal underground water pipe as a grounding electrode.

First off, current does not provide a voltage reference. As a matter of fact, it is the absence of current that produces the best voltage reference because there will not be a voltage drop associated with it.

The only difference between an 8' ground rod and the water pipe is that the water pipe is a lot longer, and therefore will reduce the overall resistance to the earthen ground connection. As for it not carrying any real current, have you never placed a clamp-on meter on the GEC between the rod and the main panel?

 

[hurk27]

Without a grounding electrode, the secondary side of a transformer has the capability to float the entire system as high as the primary-voltage.

Rick you might want to re-think this statement, if this was true we would never be allowed to have an ungrounded system which is allowed by code?

Grounded systems started way back with telegraph systems, and it was because of static energy build up on long runs of wire, this is not a problem with the short runs between the utility transformer and a buildings electrical system since most utility's bond both the primary and secondary neutrals to an electrode at the pole, and as far as most NEC compliant electrode systems even coming close as a LPS, it ain't going to happen.

While I completely agree with you on the fact the a EGS will not nor can it in most case be depended upon to open any OCPD's this is a grave myth that is perpetuated in many articles and even TV.

But my response is that any voltage placed upon the water pipe will not be brought down to the potential of Earth because of the resistance of the Earth in the close proximity of the water pipe, which will be to high to ever do this, again the only protection the water pipe can give is if it has a connection down the street to another service or several of these connections that will give it a low impedance path back to source, but again this is not the reason held in the NEC.

I think for the most part we are on the same page but we must remember that the current is not trying to return to Earth, it is trying to return back to source, other wise we would not have current in cars or airplanes. do we need ground rods for cars or air planes?:blink:

 

[iwire]

The only difference between an 8' ground rod and the water pipe is that the water pipe is a lot longer,

That and the fact it is very likely to be connected multiple times to the MGN due to the neighbors bonding.