Equipment Grounding for Ungrounded System

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tryinghard said:
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These are the idiot diagrams I was refering to.

People who propagate such nonsense belong to the flat earth society. They need to think in complete circuits, but even that they are incapable to recognize.

They do NOT show the other grounding point at the transformer.

The voltage would be evenly divided between the grounded point at the source of the voltage driver and the fault location. so if the two locations are 20' apart then for each foot there would be aproximately 6V, but since the earth resistance varies as it is not a homogenous substance it would be more in someplaces and less in others.

But hey, it's on the Internet and is published by an "expert" so it must be true.
 
peter d said:
This is the finest Merry Go Round I have ever ridden.
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Sorry sir I don't understand what you mean please clarify.

Maybe you may answer directly the questions and comment point by point to the comments to prove your position.
 
George Stolz said:
Wrong. The answer is zero.
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Please answer the other questions sir.

If the system grounding in the illustration was an ungrouded system, do you think this step potential will happen? Please answer.

If fault current is a low ARCING GROUND FAULT and its value is less than the ampere trip rating of the OCPD, do you think OCPD will still open even with a bonded EGC to the source? Please answer.

Based on Ohms law V_step potential = I_fault current times R _resistance of the earth.


Step potential will be low enough that illustration will not happen but the metal pole may still be energized and the person touching the pole will receive an electric shock equal to 120 volts if the pole is not conneted to ground.

Same principle applies to ungrounded and HRG system if one of the current carrying conductor touches the metal piece.
 
bobby ocampo said:
Sorry sir I don't understand what you mean please clarify.

Maybe you may answer directly the questions and comment point by point to the comments to prove your position.
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What I mean is that this thread has gone in circles without any type of resolution to the concerns being raised.

Yes, it has been a learning experience for many, myself included, but now it is just repeating itself.
 
weressl said:
These are the idiot diagrams I was refering to.

People who propagate such nonsense belong to the flat earth society. They need to think in complete circuits, but even that they are incapable to recognize.

They do NOT show the other grounding point at the transformer.

The voltage would be evenly divided between the grounded point at the source of the voltage driver and the fault location. so if the two locations are 20' apart then for each foot there would be aproximately 6V, but since the earth resistance varies as it is not a homogenous substance it would be more in someplaces and less in others.

But hey, it's on the Internet and is published by an "expert" so it must be true.
Click to expand...
The information that the illustration is based on comes right out of the IEEE green book. You can connect a ground rod to an ungrounded conductor and measure the voltage drop as you move away from the rod. I have done this experiment and gotten results that closely match the table in the Green Book. I also know that Mike has done this experiment an number of times at various locations. Your theory would be correct if the resistance of the earth was some what linear with distance from the rod, but it is very non-linear with a decrease in the resistance per unit of distance as you move away from the grounding electrode. This is often explained by the use of earth "shells" around the rod. The cross sectional area of each shell gets much larger as you move away from the rod and this results in a decrease in resistance.
 
weressl said:
These are the idiot diagrams I was refering to.

People who propagate such nonsense belong to the flat earth society. They need to think in complete circuits, but even that they are incapable to recognize.

They do NOT show the other grounding point at the transformer.

The voltage would be evenly divided between the grounded point at the source of the voltage driver and the fault location. so if the two locations are 20' apart then for each foot there would be aproximately 6V, but since the earth resistance varies as it is not a homogenous substance it would be more in someplaces and less in others.

But hey, it's on the Internet and is published by an "expert" so it must be true.
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I couldnt agree more and I cant believe this has gone to this point. It is surreal the cheerleading for the conclusion to this point. Prove it is what I say and preach. Set up the real ife conditions the rescources are certainly here one less Rolex to help the little people live in safety. I have never seen a pole lighting circuit pulled without a grounding conductor in 35 years.
 
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bobby ocampo said:
If the system grounding in the illustration was an ungrouded system…
Step potential will be low enough that illustration will not happen but the metal pole may still be energized and the person touching the pole will receive an electric shock equal to 120 volts if the pole is not conneted to ground.
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Why would electrocution happen with an ungrounded system? Do you understand there is no phase connection to earth at all in an ungrounded system? There will not be potential to ground earth.
 
don_resqcapt19 said:
The information that the illustration is based on comes right out of the IEEE green book. You can connect a ground rod to an ungrounded conductor and measure the voltage drop as you move away from the rod. I have done this experiment and gotten results that closely match the table in the Green Book. I also know that Mike has done this experiment an number of times at various locations. Your theory would be correct if the resistance of the earth was some what linear with distance from the rod, but it is very non-linear with a decrease in the resistance per unit of distance as you move away from the grounding electrode. This is often explained by the use of earth "shells" around the rod. The cross sectional area of each shell gets much larger as you move away from the rod and this results in a decrease in resistance.
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IF that is the case, then it is only true to SINGLE ground rods and not industrial or commercial use structures where
  1. muiltipoint grounding rods exist with interconnecting grounding cables between them
  2. steel structures in industrial plants where the 'ground' is steel decking or grating.
If the above is true then the Code is negligent in addressing other than single family dwelling installations.

The 'shells' exist, however they are immaterial since there is only a linear path exist between the ground rod and the knee of the poor fella...
 
weressl said:
IF that is the case, then it is only true to SINGLE ground rods and not industrial or commercial use structures where
  1. muiltipoint grounding rods exist with interconnecting grounding cables between them
  2. steel structures in industrial plants where the 'ground' is steel decking or grating.
If the above is true then the Code is negligent in addressing other than single family dwelling installations.

The 'shells' exist, however they are immaterial since there is only a linear path exist between the ground rod and the knee of the poor fella...
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Ouch teach em till it hurts!! Quote from the boss. I just did a 24 base parking lot with a groundrod 10'at every pole plus ground conductor #10 from bldg managers panel calculate this please. Real life.
 
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bobby ocampo said:
?Connection to earth is used to reduce the potential of the energized metal piece to earth potential. This is also the purpose of connecting the neutral of the solidly grounded system so that potential of the current carrying conductor will be limited to line to ground fault.
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Do you understand 250.142(B)?
 
bobby ocampo said:
Connection to earth is used to reduce the potential of the energized metal piece to earth potential. This is also the purpose of connecting the neutral of the solidly grounded system so that potential of the current carrying conductor will be limited to line to ground fault.
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Where are you getting this in the NEC?
 
bobby ocampo said:
Based on the illustration, what will happen if another grounding rod is installed 3 feet and 5 feet respectively and is bonded to the ground rod installed near the post with zero potential?
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What if the man were 8? tall laying down, or 5? holding a 10? stick of EMT?That?s exactly why you cannot count on earth being the same potential everywhere.

bobby ocampo said:
What is the assumed resistance of the earth in this illustration?
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This is exactly the problem with earth at any given moment!

bobby ocampo said:
To reduce step potential to ground or earth as in this illustration there are two solution. One is when fault current is low and another is when resistance is low...
If resistance to ground is reduced to a small amout because of installation of another grounding rod bonded to the first grounding rod, step potential will be reduced.
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Only at some particular location (maybe), and electrodes will be infinite; or we simply understand our installations are correct to rely on the effective ground fault paths. And oh ya they are grounded as well because 250.(A)(1) and (B)(1).
 
tryinghard said:
Why would electrocution happen with an ungrounded system? Do you understand there is no phase connection to earth at all in an ungrounded system? There will not be potential to ground earth.
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Which is why a GFCI would be worthless on an ungrounded system.

It will not be needed, nor would it function under normal conditions.
 
weressl said:
These are the idiot diagrams I was refering to.

touch.gif


People who propagate such nonsense belong to the flat earth society. They need to think in complete circuits, but even that they are incapable to recognize.

They do NOT show the other grounding point at the transformer.

The voltage would be evenly divided between the grounded point at the source of the voltage driver and the fault location. so if the two locations are 20' apart then for each foot there would be aproximately 6V, but since the earth resistance varies as it is not a homogenous substance it would be more in someplaces and less in others.

But hey, it's on the Internet and is published by an "expert" so it must be true.
Click to expand...

That is totally uncalled for and unprofessional.

The picture depicts the truth of the matter, the person will be shocked even with the other earth grounding points.

You can refuse to believe it but you will have to step over the trail of dead bodies to do so.

Many people have been killed at light poles under the conditions shown at the picture.
 
weressl said:
IF that is the case, then it is only true to SINGLE ground rods and not industrial or commercial use structures
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No such thing as a single ground rod, you already pointed that out. When Mike and Don did their experiments there where far more then a single electrode connecting the system to earth.


If the above is true then the Code is negligent in addressing other than single family dwelling installations.
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No not negligent, they just know it is impossible to accomplish what you feel is commonplace.

Try the experiment in one of your multi-grounded industrial locations and get back to us.
 
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