Grounding VS Bonding

[George Stolz]

In cases where the raceway is the EGC the process of bonding together the raceway is accomplished with the raceway but this bonding path is allowed by 250.118 to be the EGC but if the EGC is installed in nonmetallic raceways and enclosures is it bonding anything as required in 250.4(A)(3)? If not then why would we want to call it a bonding anything?

I don't quite follow. If installed in nonmetallic enclosures and raceways, then it wouldn't be grounding much of anything either, would it?

 

[jwelectric]

I don't quite follow. If installed in nonmetallic enclosures and raceways, then it wouldn't be grounding much of anything either, would it?

Yes the device or equipment the circuit is supplying.

Bonded (Bonding). Connected to establish electrical continuity and conductivity.

Grounded (Grounding). Connected (connecting) to ground or to a conductive body that extends the ground connection.
Ground. The earth.

There is a big difference between the two as anyone should understand. It is my opinion that the only misunderstanding that comes between the two is the lack of education.

Most people see this number (1/2) as one half but for many years now all I can see is one divided by two. I see it this way due to my education in math. Those who have a firm education in grounding and bonding knows the difference between bonding and grounding.

The equipment grounding conductor clears faults because of the requirements in Part II of Article 250 titled System Grounding.
Section 250.24(B) is how this is achieved.

 

[don_resqcapt19]

The way I have been taught be it right or wrong the EGC is required by 250.4(A)(2) to connect normally non?current-carrying conductive materials enclosing electrical conductors or equipment to earth and the purpose for this is to limit the voltage to ground on these materials.

That is one purpose of the EGC, but not its primary purpose.

Bonding on the other hand is the process of connecting normally non?current-carrying conductive materials enclosing electrical conductors or equipment together and to the neutral at the service disconnect as required by 250.4(A)(3) in a manner that establishes an effective ground-fault current path

That is the primary purpose of the EGC.

In cases where the raceway is the EGC the process of bonding together the raceway is accomplished with the raceway but this bonding path is allowed by 250.118 to be the EGC but if the EGC is installed in nonmetallic raceways and enclosures is it bonding anything as required in 250.4(A)(3)? If not then why would we want to call it a bonding anything?

The only way it is not bonding something is if it is not connected to something on both ends.

In my opinion, the term "grounding" should only be used for a conductor that has one of its ends directly connected to a grounding electrode.

 

[Volta]

....In my opinion, the term "grounding" should only be used for a conductor that has one of its ends directly connected to a grounding electrode.

I agree.

 

[jwelectric]

In my opinion, the term "grounding" should only be used for a conductor that has one of its ends directly connected to a grounding electrode.

Is this not exactly what it does? Even without an electrode system installed at the premises wiring the EGC connects to the Grounded conductor. Is not this grounded conductor connected to earth at the transformer supplying the premises wiring system?

I bought a CB radio for my truck. The instructions say to connect the red wire with the fuse to the positive post of the battery and the black wire to ground. Would you say this is the correct way to install this CB?

But a car does not have a ground, does it? This is where all the confusion comes into play with the word ground. The NEC defines ground as earth. The NEC has one article devoted to a conductor that is connected to earth, Article 200. Should this article be renamed? 250.24(B) requires that the EGC be connected to the grounded conductor. 250.24(A) requires that the grounded conductor be connect to earth which again is a connection of the EGC to earth. By saying ?directly? are you saying the same requirement as the grounding electrode conductor? Not even the grounded conductor has this requirement.

What type of bonding would be done by the EGC in a system outlined in 250.24(E)?

 

[electrofelon]

Is this not exactly what it does? Even without an electrode system installed at the premises wiring the EGC connects to the Grounded conductor. Is not this grounded conductor connected to earth at the transformer supplying the premises wiring system?

I bought a CB radio for my truck. The instructions say to connect the red wire with the fuse to the positive post of the battery and the black wire to ground. Would you say this is the correct way to install this CB?

But a car does not have a ground, does it? This is where all the confusion comes into play with the word ground. The NEC defines ground as earth. The NEC has one article devoted to a conductor that is connected to earth, Article 200. Should this article be renamed? 250.24(B) requires that the EGC be connected to the grounded conductor. 250.24(A) requires that the grounded conductor be connect to earth which again is a connection of the EGC to earth. By saying ?directly? are you saying the same requirement as the grounding electrode conductor? Not even the grounded conductor has this requirement.

What type of bonding would be done by the EGC in a system outlined in 250.24(E)?

This is understandably a difficult topic to reach a consensus on because we are talking about three different systems or things we are trying to accomplish, and the major parts of these systems are accomplishing two of the three things. Ok that may be confusing, let me elaborate. The three things: 1. system grounding (earthing) 2. equipment grounding (earthing) 3. bonding for fault clearing. Consider an equipment grounding conductor; it is accomplishing or part of #2 and #3. Consider a main bonding jumper; it is accomplishing or part of #1 and #3 (not used in ungrounded systems) Consider grounding electrodes and the GEC; they are accomplishing or part of #1 and #2 (only #2 on ungrounded systems). So its all kind of a mess of things that are doing double duty.

I say take article 250 and throw it in the garbage and start over. IT is not salvageable. We need a separate article for fault clearing and to not use the term ground for fault clearing. Here is one of any number of examples of problems with 250. Look at 250.24 or 250.30, Grounding service supplied/separately derived alternating current systems. Is this section discussing my #1,#2, or #3? You cant tell from the title. Another issue is part V bonding and part VI equipment grounding and EGC's. I am really at a loss why these are separate and why they feel the need to use two different terms for the same thing. Its just a complete illogical mess.

I propose the following: split 250 into two articles: 251 - system and equipment grounding (earthing) and 252 - equipment bonding. It would go something like this:

Article 251
Part 1. Scope and definitions - why we ground a system, why we connect electrical equipment to earth
Part 2. Grounding electrode system - electrodes, installation, connections, grounding electrode conductor.
Part 3. Equipment grounding - "electrical equipment enclosures and raceways in both grounded and ungrounded systems shall be connected to the GES. The methods and requirements in article 252 shall be followed to connect equipment to the grounding electrode system. Conductors and, when applicable, raceways and equipment, shall be permitted to serve the dual role of meeting the requirements in article 252 part 3 and article 252"
Part 4. System grounding - systems to be and not to be grounded, MBJ.

Article 252
Part 1. Scope and definitions - purpose of bonding in both grounded and ungrounded systems (use the term equipment bonding conductor)
Part 2. All the rules, methods, sizing, and techniques for bonding equipment and raceways.

Well that is a very brief outline of the way I would like to see it. I would like to work on it some more and fill in the holes, but I have other things I have to do at the moment. I welcome comments.

 

[don_resqcapt19]

Is this not exactly what it does? Even without an electrode system installed at the premises wiring the EGC connects to the Grounded conductor. Is not this grounded conductor connected to earth at the transformer supplying the premises wiring system?

No, the EGC is never connected directly to the grounding electrode in a code compliance system.

I bought a CB radio for my truck. The instructions say to connect the red wire with the fuse to the positive post of the battery and the black wire to ground. Would you say this is the correct way to install this CB?
But a car does not have a ground, does it?

The terms of the NEC have nothing to do with an installation in car.

...By saying ?directly? are you saying the same requirement as the grounding electrode conductor? Not even the grounded conductor has this requirement.

I am saying that the only conductor that should include the term grounding is the conductor with a direct connection to the grounding electrode. The grounded conductor is connected to the grounding electrode via a grounding electrode conductor, the white wire is not run to the grounding electrode.

What type of bonding would be done by the EGC in a system outlined in 250.24(E)?

It bonds the non current carrying parts of the electrical system together and to the grounding electrode conductor. It provides the required fault clearing path in the event of a second fault.

 

[ActionDave]

Here is another one.
Get rid of ground and use bond as you see fit. Add some "ings" to either of them as needed.

Scenario:

1- 200 amp single phase house service (service drop). (main breaker panel.... one ground to water, no rod (s))

So..... at some time along the way....the owner was told to relocate service drop and meter.

An electrician (?) relocated the drop and meter and added a main breaker to feed existing panel with SEU.

Bonded the new main breaker (neutral/ground) with the green screw, but did not add rods for that new breaker or bring water ground to that breaker.... He also did not
separate the neutrals and grounds that are in the existing panel..

With the system as it is.........besides it not being "right"....... besides paralleling the neutral and ground conductors in the SEU... what else could be dangerously wrong.

(did I mention I re-fed some pool pump equipment and added an equipotential bond grid. This equipment is fed from an existing sub panel fed from that existing main panel)?


If I were to extend the water ground....... can that ground wire be spliced ( I vaguely remember it having to be or exothermically welded......)...I'll look...

 

[jwelectric]

No, the EGC is never connected directly to the grounding electrode in a code compliance system.

Then explain just what this code section means,
250.24(B) Main Bonding Jumper. For a grounded system, an unspliced main bonding jumper shall be used to connect the equipment grounding conductor(s) and the service-disconnect enclosure to the grounded conductor within the enclosure for each service disconnect in accordance with 250.28

I could be wrong but it seems to me that the NEC is requiring that the EGC be connected to earth along with the neutral at the service.

The terms of the NEC have nothing to do with an installation in car.

You were talking about the confusion so I mentioned where a lot of the confusion comes from. In electronics chassis grounds are also used adding to the confusion

I am saying that the only conductor that should include the term grounding is the conductor with a direct connection to the grounding electrode. The grounded conductor is connected to the grounding electrode via a grounding electrode conductor, the white wire is not run to the grounding electrode.

But none the less it is connected to earth and it is connected to earth even before it becomes the white conductor. In some cases this conductor we are discussing here is even earth on the utility side.
Although this conductor is called the ?grounded conductor? in the NEC is connects to earth in the same manner as the EGC so are you saying that this conductor should be renamed and called something like the service bonding conductor or maybe the bonded return path?
Article 200 is titled ?Use and Identification of Grounded Conductors? so using your theory this article should be renamed and any place in the NEC where the term grounded conductor is mentioned should be changed. This term ?grounded conductor? is used almost three hundred times throughout the NEC when referencing the ?neutral? conductor.

I asked about 24(E) and you answered this

It bonds the non current carrying parts of the electrical system together and to the grounding electrode conductor. It provides the required fault clearing path in the event of a second fault.

Here you are admitting that the EGC connects to earth so why so adamant about this earth connection?
Let?s take a receptacle for a residential air conditioner that is supplied from a meter main panel mounted on the outside wall. Let?s install this branch circuit in PVC pipe and use a nonmetallic box with plastic in-use cover. The EGC will attach to the terminal in the panel which is connected to the grounding electrode and the grounded conductor via a bonding conductor and the other end will land on the grounding terminal of the receptacle. What is being bonded in this set up? Are you saying we are bonding the bonding terminal of the receptacle to something? When we first make this required installation nothing is plugged into the receptacle so don?t say we are bonding what ever gets plugged into the receptacle.

When I hear the term ?equipment bonding conductor? my mind goes to code sections such as this one. 250.146 Connecting Receptacle Grounding Terminal to Box. An equipment bonding jumper shall be used to connect the grounding terminal of a grounding-type receptacle to a grounded box unless grounded as in 250.146(A) through (D). The equipment bonding jumper shall be sized in accordance with Table 250.122 based on the rating of the overcurrent device protecting the circuit conductors.
This is a little different than the EGC and even sends us to a table that has a name. Table 250.122 Minimum Size Equipment Grounding Conductors for Grounding Raceway and Equipment

Over the years I have been fortunate enough to talk with a lot of electricians. Those who make new installations and those who do electrical maintenance that refer to the grounded conductor outlined in Article 200 as the common conductor. Maybe to help with this confusion we should make a proposal to have Article 200 changed to title of Use and Identification of Common Conductors. Or maybe it would be better to spend some time educating those few confused folks about just what grounding and bonding is all about.

In my personal opinion as an educator changing terms in the NEC will never replace an education nor will it relieve confusion. You don?t seem to be confused about the EGC and the reason is simply due to you learning about grounding and bonding. Before you had this knowledge do you think that calling the EGC the EBC would have given you this knowledge without study? As long as we continue to call the negative post of a battery the ground there will be confusion no matter what the green or bare wire of premises wiring systems is called. If that CB radio is not connected to ground then it will not work. The reason the lights on my trailer blink is because the ball on the truck don?t give the lights a good ground. I need to ground the lights through the plug. Always remember to disconnect the ground of the battery before removing the positive cable.

I have never seen a automobile that was grounded unless it was a RV with external power, have you?
Maybe changing the term to bonding would clear everything up.

Enough said, we have opposing opinions on this subject and this is why I love you so much, my friend.

 

[GoldDigger]

Quote Originally Posted by don_resqcapt19 View Post
No, the EGC is never connected directly to the grounding electrode in a code compliance system.

Then explain just what this code section means,
250.24(B) Main Bonding Jumper. For a grounded system, an unspliced main bonding jumper shall be used to connect the equipment grounding conductor(s) and the service-disconnect enclosure to the grounded conductor within the enclosure for each service disconnect in accordance with 250.28

I could be wrong but it seems to me that the NEC is requiring that the EGC be connected to earth along with the neutral at the service.

I think that your confusion here is the meaning of the word "directly". The Ground Electrode Conductor (GEC) is what connects directly from the ground electrode itself to the common grounding point at the service disconnect, and both one end of the main bonding jumper and the various EGCs are connected to the same point.
The sizing rules for the GEC are different from the rules for EGCs, which are also different from the rules for grounded conductors.

If C is required to connect A to B, then A and B are not "directly" connected. They are still connected though. Or maybe bonded.

 

[jwelectric]

I think that your confusion here is the meaning of the word "directly". The Ground Electrode Conductor (GEC) is what connects directly from the ground electrode itself to the common grounding point at the service disconnect, and both one end of the main bonding jumper and the various EGCs are connected to the same point.
The sizing rules for the GEC are different from the rules for EGCs, which are also different from the rules for grounded conductors.

If C is required to connect A to B, then A and B are not "directly" connected. They are still connected though. Or maybe bonded.

Once again are we going to also change the title of Article 200 because it does not directly connect to earth?

Just to be clear I am not confused about how it connects to earth either the EGC or the grounded neutral conductor but both do connect to earth via the grounding electrode conductor so if we are going to call the EGC the equipment bonding conductor because it does not directly connect to earth then what are we going to call the grounded conductor because it doesn't connect directly to earth either?

Now I am having problems on what to call the ungrounded conductors of a system as they don't directly connect to the windings of the transformer. Maybe call them the bonded ungrounded conductors.

 

[George Stolz]

Mike, you don't find the language in the NEC just a little bit daunting for the student, as it stands right now? I happen to be covering this very topic with my third year students right now, and personally I find that while students tend to grasp the base concepts of the purpose of grounding and the purpose of bonding fairly easily, the nomenclature is a hinderance.

The book I am teaching from is a good book, and starts out with essentially an apology to the student for the terminology in the NEC. He then turns right around and calls a light pole bearing a ground rod and no EGC "improperly grounded."

I'm with Don, the terminology in the NEC stinks, and does not lend itself to instruction as well as it could if they'd just call a spade a spade.

 

[jwelectric]

Mike, you don't find the language in the NEC just a little bit daunting for the student, as it stands right now?

Not at all. When it comes to grounding and bonding I start with 250.4 as this is the purpose of the entire article and explain the rest of the article is how the requirement in Section 250.4 is accomplished.

I do not inject any opinion but only teach what is printed and try to keep the opinions of other authors out of the picture. After we discuss 250.4 we then go into a discussion about the automobile battery in their car and just where the ground terminal is to be found. As it relates to the NEC there is no such thing as ground in an automobile. The confusion goes away in the first class on grounding and bonding.

With a proposal to change the name of the equipment grounding conductor to equipment bonding conductor then we must figure out what to call the grounded conductor of a system. Maybe a sister proposal should be included to rename Article 200 to the Common Conductor.
Then we must change the reasons for the earth connection found in 250.4 and the fact that metal enclosures for electrical equipment needs an earth connection to limit the voltage to earth on these items.

A utility pole that has an electrode but no grounding conductor from the neutral of the utility system to the electrode is not grounded but then again a utility pole does not need to be grounded or bonded unless it is a metal pole. The system mounted on the pole is improperly grounded. Send a note to the author on his misuse of the purpose of the earth connection. It is not to ground the wooden pole but to ground the system mounted on the pole. I suppose if one desired they could connect plastic to earth but that would be outside the scope of the NEC.

 

[ActionDave]

.... you don't find the language in the NEC just a little bit daunting for the student, as it stands right now?

Yes. Exactly!
Bond, bonding, bonded, grounded, grounding,..... main bonding jumper, system bonding jumper, equipment bonding,.... supply side bonding connector/ jumper or a system bonding something or other if it is an SDS but.... if it is a service then you need a main bonding connector/connection; it does the same thing but for some reason we need to add some new words to the code because we need a reason to feel important every other year....
STOP RIGHT NOW! Before we go any further....

I happen to be covering this very topic with my third year students right now, and personally I find that while students tend to grasp the base concepts of the purpose of grounding and the purpose of bonding fairly easily, the nomenclature is a hinderance.

If I say Equipment Grounding Conductor you know exactly what I am talking about. I sorted it out back in the nineteen nineties and I bet you did too.

 

[George Stolz]

Not at all.

Good for you!

God bless.

 

[jwelectric]

Good for you!

God bless.

God Bless you too my friend

 

[don_resqcapt19]

Once again are we going to also change the title of Article 200 because it does not directly connect to earth?

...

There is nothing in Article 200 about grounding conductors of any kind. There is nothing to suggest that a grounded conductor is directly connected to the grounding electrode.

The use of the word "grounding" for any conductor that does not physically directly connect to the grounding electrode is what I object to.

The grounded conductor does not physically run to the grounding electrode, it is connected to the grounding electrode conductor at the service equipment. The EGC does not run physically to the grounding electrode. It is connected to the grounding electrode conductor and the grounded conductor (if there is one) via the main bonding jumper at the service equipment or by the system bonding jumper at a SDS.

 

[jwelectric]

There is nothing in Article 200 about grounding conductors of any kind. There is nothing to suggest that a grounded conductor is directly connected to the grounding electrode.

The use of the word "grounding" for any conductor that does not physically directly connect to the grounding electrode is what I object to.

The grounded conductor does not physically run to the grounding electrode, it is connected to the grounding electrode conductor at the service equipment. The EGC does not run physically to the grounding electrode. It is connected to the grounding electrode conductor and the grounded conductor (if there is one) via the main bonding jumper at the service equipment or by the system bonding jumper at a SDS.

Now I am getting confused so this renaming is just not going to work. Ground, grounded, grounding all imply a connection to earth. Ground fault implies that a fault has occurred to earth.

The definition of ground, past, present, or future is earth. I remember this as a kid. Mom would say, "get up off that wet ground before I whip your butt."


If we are to rename the EGC then we must rename the neutral as the NEC now refers to it as the grounded conductor. This in itself implies that it is connected to earth.

 

[don_resqcapt19]

Now I am getting confused so this renaming is just not going to work. Ground, grounded, grounding all imply a connection to earth. Ground fault implies that a fault has occurred to earth.

The definition of ground, past, present, or future is earth. I remember this as a kid. Mom would say, "get up off that wet ground before I whip your butt."


If we are to rename the EGC then we must rename the neutral as the NEC now refers to it as the grounded conductor. This in itself implies that it is connected to earth.

Mike,
That is fine if that is how you see it.

That is not how I see it. The only word that implies a direct physical connection to the earth, to me, is the word "grounding".

If you were to connect the white wire to the grounding electrode, would the inspector be correct to red tag the job? If you were to connect the equipment grounding conductor to the grounding electrode would the inspector be correct to red tag the job? In these questions, connect means to physically run the conductor in question to the grounding electrode and physically connect the conductor to the grounding electrode.

 

[jwelectric]

Mike,
That is fine if that is how you see it.

That is not how I see it. The only word that implies a direct physical connection to the earth, to me, is the word "grounding".

If you were to connect the white wire to the grounding electrode, would the inspector be correct to red tag the job? If you were to connect the equipment grounding conductor to the grounding electrode would the inspector be correct to red tag the job? In these questions, connect means to physically run the conductor in question to the grounding electrode and physically connect the conductor to the grounding electrode.

If this is your idea of connected to then that explains your confusion or why you think it is confusing.
Branch circuits are connected to the secondary of the transformer, if they weren't then we wouldn't have any power in our homes.

Take a few minutes to study Article 100. Maybe this will help clear your head.
The definition of ground be it past (ed) or present (ing) means earth

Ground. The earth.
Ground Fault. An unintentional, electrically conducting connection between an ungrounded conductor of an electrical circuit and the normally non?current-carrying conductors, metallic enclosures, metallic raceways, metallic equipment, or earth.



Grounded (Grounding). Connected (connecting) to ground (see definition) or to a conductive body that extends the ground connection.



But to an auto person it is the negative post of a battery. To moms it means go to your room. To electronics it means the chassis

All that matters to an electrician or inspector or even an engineer is what the NEC says in Article 100, the earth. The neutral is connected to earth thus it is called the grounded conductor.