Grounding VS Bonding

[Sahib]

Golddigger:
Yes. The lightning current may also be considered as 'fault current' and there should be ground connection to allow it to pass to ground safely if EBC alone is not able to dissipate the lightning energy safely. Then EGC may also be required to do it.

 

[jwelectric]

Sahib

There are some fine folks that are confused about the purpose of connecting noncurrent carrying metal that contains electrical equipment to earth. For some reason they are blinded by the main or system bonding.

They are all hung up on voltages and currents and the amount of voltages and currents in an electrical system and the resistance of earth.

But on the other hand there some that have an understanding of such things as lightning, surges, unintentional contact with high voltage, and stabilizing and the need for an earth connection in these cases.

Call the conductor whatever you want to call the conductor but the requirement of what the conductor does doesn?t change. The entire requirement of what the conductor is to do can be found in one section of Article 250. The rest of Article 250 tells us how to accomplish this requirement but alas, some want to take Article 250 and say this is what we are required to accomplish.
The following general requirements identify what grounding and bonding of electrical systems are required to accomplish.
The prescriptive methods contained in Article 250 shall be followed to comply with the performance requirements of this section.

There is no primary or secondary reason and one is just as important as the other.
There is a requirement to bond the earthing conductor to the earthed conductor to clear faulted current but it does not change the requirement to earth the conductor for the four reasons outlined in the requirement identified for what the conductor is to accomplish thus it is named the equipment grounding conductor.

 

[kkmaj1948]

This is the best definition for Grounding and bonding ever!!!!!!

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

That is the primary purpose of the EGC.

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.

 

[robbietan]

grounding will not prevent or mitigate damage from a direct lightning strike.

a taboo topic for equipment vendors

 

[DanS26]

Wow! What a read.

Everyone (well almost everyone) agrees on the theory but the main controversy is over terminology.

This entire tread is about ground, grounded, grounding, verses bond, bonded, and bonding. How ludicrous when the solution is to just change the terminology. More time, effort and confusion is wasted because the code writers will not see the underlying problem of basic labels.

Let me be the first to suggest terminology clarification:

The ungrounded conductor becomes the "power conductor"
The grounded conductor becomes the "neutral conductor"
The equipment grounding conductor becomes the "safety conductor"
The grounding electrode conductor becomes the "earthing conductor"
The grounding electrode becomes the "earthing rod or earth connection"

Do you notice a pattern here? The word "ground' and derivatives are eliminated and thus 90% of the confusion. If you are a code writer or can influence the code writers, lets start here.

 

[GoldDigger]

Let me be the first to suggest terminology clarification:
[1] The ungrounded conductor becomes the "power conductor"
[2] The grounded conductor becomes the "neutral conductor"
[3] The equipment grounding conductor becomes the "safety conductor"

If only it were that simple. :happysad: And you are far from the first, even for this exact combination.
1. There is no "the" ungrounded conductor. There may be three in three-phase, four in two-phase, either two or one in single-phase, etc. So there would be power conductors. But the grounded conductor would be just as much a path for the power as the ungrounded conductor. It does not really convey the distinction. Maybe since it is not bonded to the safety conductor, it would be an unsafe conductor.
2. Not all grounded/earthed/safe conductors are neutral conductors, and in a few special cases neutral conductors are not necessarily grounded. Try again for that one.
3. That makes some sense, and it at least has the advantage of starting off with a new term that does not have a lot of baggage associated with it. But there is the common usage of the "safety ground" as distinct from the grounded circuit conductor. And, of course, the fact that it is a safety "ground" does not convey that what is important is that it is a fault clearing conductor with the secondary purpose of minimizing the touch potential between metal equipment parts and shells and other things in the environment, both during and separate from a fault.

 

[ActionDave]

Let me be the first to suggest terminology clarification:

The grounding electrode conductor becomes the "earthing conductor"
The grounding electrode becomes the "earthing rod or earth connection".

I'll go along with you on these two.

 

[mike1061]

What about calling the EGC the fault clearing conductor?
Thanks
Mike

 

[ActionDave]

What about calling the EGC the fault clearing conductor?
Thanks
Mike

What about sticking with Equipment Grounding Conductor. Everybody that cares enough to know what it is knows what it does. Stay consistent and spread the word is my take on it.

 

[ggunn]

The ungrounded conductor becomes the "power conductor"
The grounded conductor becomes the "neutral conductor"
The equipment grounding conductor becomes the "safety conductor"
The grounding electrode conductor becomes the "earthing conductor"
The grounding electrode becomes the "earthing rod or earth connection"

"Earth" is not a verb, is it?

I am in favor of leaving it the way it is and educating folks to use the terms correctly. That way it's only those who don't understand them now who have to be taught. Making the changes you suggest would make it necessary to educate everyone and force all those who are correct today to change their vocabulary. Until all those folks die off or otherwise leave the workforce there would be two terms for everything - the old term and the new term - and translations between old timers and rookies would be necessary. That's just silly, IMO.

 

[GoldDigger]

"Earth" is not a verb, is it?

Actually, it is in most of the English speaking electrical world.
To earth something is exactly what we mean by to ground something.
"Ground" is not a verb, is it?

Now if you ask about whether you can "dirt" something, you have a better point.

 

[ggunn]

Actually, it is in most of the English speaking electrical world.

We fought a WAR back in 1776 not to have to use silly words like "loo" for bathroom, "flat" for apartment, and "boot" for trunk!

 

[GoldDigger]

We fought a WAR back in 1776 not to have to use silly words like "loo" for bathroom, "flat" for apartment, and "boot" for trunk!

Don't forget garter.

 

[ggunn]

Don't forget garter.

http://en.wikipedia.org/wiki/Order_of_the_Garter ?

 

[tom baker]

I am in favor of leaving it the way it is and educating folks to use the terms correctly.

Exactly. "we have met the enemy and they is us" Pogo. Trade useage is what gets electricians confused.
I need to pull a ground
What size ground for a 200 amp service?
What size ground for a ground rod

CMP 5 has done a great job in clearing up the fog in art 250. It was confusing, but not so any more.

 

[electrofelon]

What about calling the EGC the fault clearing conductor?
Thanks
Mike

There is no perfect word because remember the "EGC" is serving more than one purpose - it is fault clearing AND connecting equipment to earth. The MBJ is also serving two different unrelated purposes. The grounding electrode conductor is also serving two purposes generally. I think this is what is so confusing is many people are not taught that fault clearing, equipment earthing and system earthing are different things serving different purposes and that there some parts of an electrical system my serve more than one of these at one time.

 

[GoldDigger]

There is no perfect word because remember the "EGC" is serving more than one purpose - it is fault clearing AND connecting equipment to earth. The MBJ is also serving two different unrelated purposes. The grounding electrode conductor is also serving two purposes generally. I think this is what is so confusing is many people are not taught that fault clearing, equipment earthing and system earthing are different things serving different purposes and that there some parts of an electrical system my serve more than one of these at one time.

:thumbsup::thumbsup:

 

[mike1061]

many people are not taught that fault clearing, equipment earthing and system earthing are different things serving different purposes

I'm one of those guys. I have no idea what "equipment earthing and system earthing" are, nor why you would need to earth something. Other then to carry fault current.
Thanks
Mike

 

[ActionDave]

I'm one of those guys. I have no idea what "equipment earthing and system earthing" are, nor why you would need to earth something. Other then to carry fault current.
Thanks
Mike

The earth is never to be relied on to carry fault current.

Know where to bond and how (building steel, ground rods, ufer, water pipe......) and know how to establish a circuit to clear a fault. Keep the circuit that carries current and is connected to earth separate from the circuit that clears a fault except at that one point where they are bonded together. That's it.

Did I miss anything?

 

[mike1061]

The earth is never to be relied on to carry fault current.

Know where to bond and how (building steel, ground rods, ufer, water pipe......) and know how to establish a circuit to clear a fault. Keep the circuit that carries current and is connected to earth separate from the circuit that clears a fault except at that one point where they are bonded together. That's it.

Did I miss anything?

Maybe, maybe not.
I'd like to think that I am doing those things. I follow the rules I've been taught. But it still doesn't mean I understand all of the reasons why.
The quote I replied to said this "the "EGC" is serving more than one purpose - it is fault clearing AND connecting equipment to earth." I don't understand at all the earthing part. As I understood it (until now) the EGC was to carry fault current back to the neutral buss, which is in turn connected to earth via the GEC thru the water service which is connected to earth. The current would flow thru the earth to the wire that runs up the side of the utility pole.
Please correct all that you see fit.
Thanks
Mike