earthing. the ECMag article

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bullheimer

bullheimer

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okay so i never heard of this term before, it appears that earthing is installing a ground rod for an equipment ground w/o any ground wire back to the panel. so since this is a big deal, in a lightening strike anyway, i was wondering to myself what is the diff btwn that danger and if someone where to install a ground rod on an outbuilding that was fed with 3 wire. wouldnt that be the same thing? maybe not since the third wire is a ground, but ..

how bout those two wire outlets to a tv or computer we might have run a seperate ground wire down to a ground rod just for that outlet so we could put a three prong outlet there?

also, i want to apologize for not being able to say which issue i read the article in. i can't find it at the moment.
 
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bullheimer said:
okay so i never heard of this term before, it appears that earthing is installing a ground rod for an equipment ground w/o any ground wire back to the panel. so since this is a big deal, in a lightening strike anyway, i was wondering to myself what is the diff btwn that danger and if someone where to install a ground rod on an outbuilding that was fed with 3 wire. wouldnt that be the same thing? maybe not since the third wire is a ground, but ..

how bout those two wire outlets to a tv or computer we might have run a seperate ground wire down to a ground rod just for that outlet so we could put a three prong outlet there?

also, i want to apologize for not being able to say which issue i read the article in. i can't find it at the moment.
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In no case is it allowed to install an electrode to take the place of the EGC, Earth (or the connection to it) is way to high of an impedance to open any OCPD, never, never do this!!!! or you could get someone killed.
 
hurk27 said:
In no case is it allowed to install an electrode to take the place of the EGC, Earth (or the connection to it) is way to high of an impedance to open any OCPD, never, never do this!!!! or you could get someone killed.
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Okay, with that said ( and i agree completely ) would it do any harm to drive a ground rod for lightning protection with the GEC to panel?
 
Gac66610 said:
Okay, with that said ( and i agree completely ) would it do any harm to drive a ground rod for lightning protection with the GEC to panel?
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Well we do it all the time as the NEC requires it or at least some kind of electrode, but will it protect you from lightning???? I wouldn't not want to bet on it, in-fact the University of Florida did a test on this very subject back in 2006 and less then I think 5% (this might be wrong I try to look it up) actually went to the ground rod, so in my view unless you install a fortified LPS system you not going to get much protection from a rod stuck in the ground.

There are many myths when it comes to lightning even by the most well educated who don't understand the high frequency nature of lightning or how high frequency current flows on conductors or conductive pathways, many who are in to radio will understand it but most who do not understand RF will be lost as to understanding how lightning works.

Here is one example:
A 25' run of #6 awg can be in the meg ohms when the impedance is calculated at 10 MHz, so not much good for keeping a difference of voltage potential from developing across such a high impedance is it? yet a 24 awg conductor can be a low impedance path at a given high frequency, so as you can see it can be very complicated to understanding HF theory.

Also when you get into HF the electrons travels on the outside of the conductive paths, so this is why most conductors are design to have a larger surface area and why we see braided flat cable run in a LPS system.
 
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shouldn't have opened my mouth. now i gots to find the rag. like the toimenader: Ahhll be bacch! (dont hold your breath, and no need to wait )
 
ActionDave said:
I like the term "earthing" it eliminates confusion. Much better than grounded and grounding.
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I agree and have actually been using the term more and more the past few years.

Roger
 
It stops right before the earthing bullet tho so here is that:

*Grounding electrode (earthing). This term refers to the method by which the facility grounding system is connected and referenced to earth. The most common grounding electrode for small facilities is a metallic ground rod, but earthing systems for larger buildings can and should be more elaborate and include the means by which to inspect and test these systems. periodically. A grounding electrode system that is buried in earth or encased in concrete and then forgotten is often the source of increasing problems as the building ages and the grounding electrodes deteriorate. and for giggles:
*Lightning abatement. Some facilities use air terminals (aka lightning rods), to direct lightning strikes away from power equipment, but these devices are often connected to the grounding system in such a way that they have the opposite effect-unintentionally bringing lightning energy into facility structural steel, low voltage transformer windings, and, subsequently, sensitive building loads.. and
*Signal-reference grounding. which i don't feel like adding.

it goes back to explain the cure for the isolated ground rod so i will throw that in:

"Resolving the issue: The immediate solution to the example plant's illegal ground rod (Fig2), was to remove the shock hazard. This was done by connecting a grounding conductor (1/0) from the ground rod to the nearest part of the building grounding system-in this case, the structural steel. this connection eliminated the shock potential during storms by reducing the resistance btwn the ground rod and the building grounding system.
The next step was to eliminate the wiring errors and install a ground wire from the source to the CNC machine."....
and "In summary, the plant in the example had installed a CNC process machine in accordance with the mfgr's instructions. Unfortunately, those recommendations included the requirement for a separate ground rod to serve as the only means of equipment grounding. While this practice may reduce data errors in sensitive process machines, it violates the NEC, creates a shock hazard for employees, and causes a potential difference that may damage sensitive electronic components."

article by Larry Ray and S. Frank Waterer
 
ActionDave said:
I like the term "earthing" it eliminates confusion. Much better than grounded and grounding.
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We don't need to use a new term. We just have to get the NEC to use the existing ones correctly. Much of what the NEC calls grounding is really bonding.

What exactly does earthing mean? Is it only used for the connection to earth, or is it also used for what we incorrectly call the Equipment Grounding Conductor?
 
don_resqcapt19 said:
We don't need to use a new term. We just have to get the NEC to use the existing ones correctly. Much of what the NEC calls grounding is really bonding.

What exactly does earthing mean? Is it only used for the connection to earth, or is it also used for what we incorrectly call the Equipment Grounding Conductor?
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Amen.
 
from the article linked to above:

"Earthing is the attachment of a bonded metallic system to earth, typically through ground rods or other suitable grounding electrodes. The NEC prohibits earthing via isolated ground rods as the only means of equipment grounding. Nevertheless, some manufacturers of sensitive machinery actually encourage this practice in their installation manuals, in order to reduce "no problem found" service calls associated with machine errors and rebooting." Second Paragraph of linked article.
 
don_resqcapt19 said:
We don't need to use a new term. We just have to get the NEC to use the existing ones correctly. Much of what the NEC calls grounding is really bonding.

What exactly does earthing mean? Is it only used for the connection to earth, or is it also used for what we incorrectly call the Equipment Grounding Conductor?
Click to expand...
I know I am not going to win any converts, and that is fine with me, but I like "earth and/or earthing." Maybe it is because I watch a lot of British TV programs, none the less....

Earth means one thing: The surface we all walk upon, or what is beneath what we are walking upon when it is covered by something like concrete or asphalt. The new art. 100 definition seems to agree.

When it comes to describing equipment grounds as bonding; I hate it. IMO there is one "Bond" and it is at the Service or an SDS. Keep it at that and every thing else is simple when you understand how electrical systems are supposed to work.
 
No matter if you use "earthing" or "grounding", the term only works if you use it correctly. Those two terms should only be used with the conductors that directly connect to the grounding electrode(s). Everything else that the code calls grounding is really bonding. If you just change "grounding" to "earthing" in the code, you have not really made any change.
 
don_resqcapt19 said:
No matter if you use "earthing" or "grounding", the term only works if you use it correctly. Those two terms should only be used with the conductors that directly connect to the grounding electrode(s). Everything else that the code calls grounding is really bonding. If you just change "grounding" to "earthing" in the code, you have not really made any change.
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I agree with your premise, and other posters, but I was sitting here running the terms and the applications around, and in a strictly English (American) dictionary definitions sense, you can use those terms along with bonding, grounded etc. "correctly" in all of the various ways. Just like everything in life, us oldtimers get entrenched and turning from our path takes dynamite. It would be beneficial to have a discussion and a decision to recreate NEC definitions the clearly define and separate the various intentions and designs of the code. Then we could all rumble. I, for example, do like the term earthing for the connection from generated electricity to the earth potential in all cases. I have always felt that the use of "grounded conductor" was kind of like a test to weed out the dummies (not is a good way!) I would vote for the term "common" for all references to a common conductor that has the potential to share the return of different potentials to the source, whether grounded (bonded to an earth point) or not. For purposes of reducing confusion the NEC could define Ground, grounding, grounded, as variation of the term ground, all representive of the entire system intended to create a single potential for all metal that may become energized, associated with a building or service "Bonding" can be defined as "any intentional, electrically continuous connection to the (above defined) ground system.

Just some quickly developed thoughts, not finalized, but maybe a foundation for an approach.
 
Strathead said:
"Bonding" can be defined as "any intentional, electrically continuous connection to the (above defined) ground system.
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Review the ROP's for past code cycles and look for Don's proposals on this subject.

BTW, Bonding can not always be refering to a grounded system.

Roger
 
Strathead said:
For purposes of reducing confusion the NEC could define Ground, grounding, grounded, as variation of the term ground, all representive of the entire system intended to create a single potential for all metal that may become energized, associated with a building or service "Bonding" can be defined as "any intentional, electrically continuous connection to the (above defined) ground system.

Just some quickly developed thoughts, not finalized, but maybe a foundation for an approach.
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The NEC has eliminated much confusion starting in the 08.

Ground - The earth.

Bonded - Connected to establish electrical continuity and conductivity.

That's from the 08 NEC. I see no confusion. The new definitions are pretty straight forward.

To me, your suggestion is a bit confusing.
 
K8MHZ said:
The NEC has eliminated much confusion starting in the 08.

Ground - The earth.

Bonded - Connected to establish electrical continuity and conductivity.

That's from the 08 NEC. I see no confusion. The new definitions are pretty straight forward.

To me, your suggestion is a bit confusing.
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Then why does the code still use the term "equipment grounding conductor" when it is very clear that the term should be "equipment bonding conductor"?
 
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