Portable Generators and Ground Rods
- Thread starter iwire
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Re: Portable Generators and Ground Rods
You guys are really just jerks.
Your little picture proves what I have been saying all along and that is that current does flow through the ground and back to the source. I never said that it was not effective. Thats why we install equipment grounds on branch circuits. Take the ground rod off and he will get more than 90 volts. On the scenario that I presented there is no equipment ground nor is one required. When that neutral is lost it will seek a path back to the source. On the generator the manufacture bonds the neutral to the frame which is bonded to a ground rod. Current can then flow from the grounding electrode thru earth to the ground rod on the generator thru the frame to the point where the neutral is bonded to the frame back to the source. Its not rocket science. If you grab the frame will you still get shocked? I don't know I wasn't argueing that point. It just seems to me that the ground rod serves more than one purpose. If not why bond the neutral to the frame? Why not just run an equipment ground to the frame and require that the generator have lightning protection to satisfy your whims. On a portable they bond the neutral and all the equipment grounds to the frame. Its like that first point of disconnect on a service.
I fully intend to keep installing things the way that I have been. And that is Per The NEC. I think that you should submit your ideas to the code making panels seeing how adamant you are about these installations being unsafe. After all the code is all about protecting people and property. They change the code I change my wiring practices. But until then it is business as usual. Now some of you may want to slam this attitude. I don't really care. My installations are looked at by Inspector after inspector and they all pass. Thats what counts. And I have lots of installations to my credit both large and small. And I dare say probaly more than all of you combined. I have installed generators with Utility paralleling capabilities down to home standby generators. So don't even begin with saying I have no electrical background.
Finally, Your treatment of Mr. Hickman Who represents the IBEW on the code making panel is deplorable and the reason that I call you jerks. One, we are not the same person or related as far as I know. However, He is at least trying to make a difference. Unlike you Electrical Gods who are all talk and no action. I came to this forum looking for an answer to a question that I had. I think that I will stick to the forums that I have used in the past. They may be slow but at least they are sincere.....
You guys are really just jerks.
Your little picture proves what I have been saying all along and that is that current does flow through the ground and back to the source. I never said that it was not effective. Thats why we install equipment grounds on branch circuits. Take the ground rod off and he will get more than 90 volts. On the scenario that I presented there is no equipment ground nor is one required. When that neutral is lost it will seek a path back to the source. On the generator the manufacture bonds the neutral to the frame which is bonded to a ground rod. Current can then flow from the grounding electrode thru earth to the ground rod on the generator thru the frame to the point where the neutral is bonded to the frame back to the source. Its not rocket science. If you grab the frame will you still get shocked? I don't know I wasn't argueing that point. It just seems to me that the ground rod serves more than one purpose. If not why bond the neutral to the frame? Why not just run an equipment ground to the frame and require that the generator have lightning protection to satisfy your whims. On a portable they bond the neutral and all the equipment grounds to the frame. Its like that first point of disconnect on a service.
I fully intend to keep installing things the way that I have been. And that is Per The NEC. I think that you should submit your ideas to the code making panels seeing how adamant you are about these installations being unsafe. After all the code is all about protecting people and property. They change the code I change my wiring practices. But until then it is business as usual. Now some of you may want to slam this attitude. I don't really care. My installations are looked at by Inspector after inspector and they all pass. Thats what counts. And I have lots of installations to my credit both large and small. And I dare say probaly more than all of you combined. I have installed generators with Utility paralleling capabilities down to home standby generators. So don't even begin with saying I have no electrical background.
Finally, Your treatment of Mr. Hickman Who represents the IBEW on the code making panel is deplorable and the reason that I call you jerks. One, we are not the same person or related as far as I know. However, He is at least trying to make a difference. Unlike you Electrical Gods who are all talk and no action. I came to this forum looking for an answer to a question that I had. I think that I will stick to the forums that I have used in the past. They may be slow but at least they are sincere.....
G
Guest
Guest
Re: Portable Generators and Ground Rods
Hickman,
Please don't lump us all onto one slag heap.
First off, I'm probably the only one dumb enough to assume you were the IBEW NEC Hickman. If I had noticed your forum member # I would not have made that erroneous assumption. I am a newbie here (one month) so I'm still getting my forum legs. Please forgive me, and please don't hold my mistaken assumption against anybody else. It really doesn't matter which Hickman you are anyway. I just tried to put a face to the name and I was wrong in my assumption.
I also assume everybody here is a guy. I should be more openminded. I do remind myself frequently to try and keep my posts gender neutral. I would like to see more women in the trades. Right now there are so few visible women that it's easy to fall into the mindset that they don't exist.
My electrical experience is deep and broad, but due to a variety of circumstances (good and bad) it is now dated, rusty, and dusty. I am participating in this forum to dust off my knowledge, and to learn some new concepts. In a way I'm fortunate to have a time of new beginnings.
Like you I thought I understood grounding. This forum has opened my eyes to the other aspects of grounding; it's real main purpose; and it's benefits and dangers. Wow! I am lucky to be starting "fresh" and I'm lucky to be somewhat openminded about new and/or conflicting ideas.
Electricity is serious business. Mistakes are deadly. I have rarely been shocked, but my next shock could be my last. You just never know and must be ever vigilant. Part of that vigilance is being open-minded about better ways to make it safe.
I have not offered anything to this discussion because either I have nothing to add, or my knowledge has already been covered. The scope of the posts so far have far exceeded anything that would have come from my mind a short month ago.
I am truly sorry if any comments that I made caused you any ill will, frustration, or anxiety. That was not my intention.
I believe, and correct me if I'm wrong that iwire started this discussion about portable generators, but you (Hickman) may be talking about permanent generators. Clarification of that point would be helpful to me.
Again, I have nothing helpful to offer to this thread other than to say it's a very important topic and finding the right answer is paramount.
Note: You may find some benefit in using Private Messaging to air any personal matters more discreetly. It may even clear up some personal disagreements that have popped up here. You can click on a member nickname and send them an Instant Private Message. It works for me.
I am hoping you can get this thread back on track and out of the ditch. It's a really good thread.
Most respectfully,
../Wayne C.
[Note: I've gone back to using ieSpell as UBB Code? Spell Check is too slow for me]
Hickman,
Please don't lump us all onto one slag heap.
First off, I'm probably the only one dumb enough to assume you were the IBEW NEC Hickman. If I had noticed your forum member # I would not have made that erroneous assumption. I am a newbie here (one month) so I'm still getting my forum legs. Please forgive me, and please don't hold my mistaken assumption against anybody else. It really doesn't matter which Hickman you are anyway. I just tried to put a face to the name and I was wrong in my assumption.
I also assume everybody here is a guy. I should be more openminded. I do remind myself frequently to try and keep my posts gender neutral. I would like to see more women in the trades. Right now there are so few visible women that it's easy to fall into the mindset that they don't exist.
My electrical experience is deep and broad, but due to a variety of circumstances (good and bad) it is now dated, rusty, and dusty. I am participating in this forum to dust off my knowledge, and to learn some new concepts. In a way I'm fortunate to have a time of new beginnings.
Like you I thought I understood grounding. This forum has opened my eyes to the other aspects of grounding; it's real main purpose; and it's benefits and dangers. Wow! I am lucky to be starting "fresh" and I'm lucky to be somewhat openminded about new and/or conflicting ideas.
Electricity is serious business. Mistakes are deadly. I have rarely been shocked, but my next shock could be my last. You just never know and must be ever vigilant. Part of that vigilance is being open-minded about better ways to make it safe.
I have not offered anything to this discussion because either I have nothing to add, or my knowledge has already been covered. The scope of the posts so far have far exceeded anything that would have come from my mind a short month ago.
I am truly sorry if any comments that I made caused you any ill will, frustration, or anxiety. That was not my intention.
I believe, and correct me if I'm wrong that iwire started this discussion about portable generators, but you (Hickman) may be talking about permanent generators. Clarification of that point would be helpful to me.
Again, I have nothing helpful to offer to this thread other than to say it's a very important topic and finding the right answer is paramount.
Note: You may find some benefit in using Private Messaging to air any personal matters more discreetly. It may even clear up some personal disagreements that have popped up here. You can click on a member nickname and send them an Instant Private Message. It works for me.
I am hoping you can get this thread back on track and out of the ditch. It's a really good thread.
Most respectfully,
../Wayne C.
[Note: I've gone back to using ieSpell as UBB Code? Spell Check is too slow for me]
karl riley
Senior Member
Re: Portable Generators and Ground Rods
Dear Mr Hickman,
frustration levels go up when a member just seems impervious to electrical facts, logic, and quotes from the NEC. You might re-check your Code book and see what it says about the functions of grounding electrodes. And sometime in the future you may re-visit this forum and say, "Hey guys, I called you jerks back then, but guess what I found out....."
Good luck,
Karl
Dear Mr Hickman,
frustration levels go up when a member just seems impervious to electrical facts, logic, and quotes from the NEC. You might re-check your Code book and see what it says about the functions of grounding electrodes. And sometime in the future you may re-visit this forum and say, "Hey guys, I called you jerks back then, but guess what I found out....."
Good luck,
Karl
- Location
- Massachusetts
Re: Portable Generators and Ground Rods
Mr. Hickman, from one jerk to another, I hope you at least come away from this angry enough to open a book and be open minded to see what the purpose of a ground electrode in earth is really for. Next time you are in a car, plane, or boat maybe you might ask yourself if a connection to earth is necessary for electrical safety.
If you go back to page one and see the first five post, the correct answer was given for the application. Since the vehicle-mounted generator was being used on hardwired equipment a ground electrode was required, and I think everyone agrees that is what the code required.
None of the members on this board would advocate an intentional violation of the code, but we do discuss why some aspects are required. In this case I think we agreed in this application a ground rod did not serve any real purpose other than discharging static or possible contact with HV or MV, which meets two of the five reasons a earth connection is required. I will let you discover the other three reasons for a earth connection.
Anyway good luck to you and god bless.
Dereck
Mr. Hickman, from one jerk to another, I hope you at least come away from this angry enough to open a book and be open minded to see what the purpose of a ground electrode in earth is really for. Next time you are in a car, plane, or boat maybe you might ask yourself if a connection to earth is necessary for electrical safety.
If you go back to page one and see the first five post, the correct answer was given for the application. Since the vehicle-mounted generator was being used on hardwired equipment a ground electrode was required, and I think everyone agrees that is what the code required.
None of the members on this board would advocate an intentional violation of the code, but we do discuss why some aspects are required. In this case I think we agreed in this application a ground rod did not serve any real purpose other than discharging static or possible contact with HV or MV, which meets two of the five reasons a earth connection is required. I will let you discover the other three reasons for a earth connection.
Anyway good luck to you and god bless.
Dereck
big john
Senior Member
- Location
- Portland, ME
Re: Portable Generators and Ground Rods
If I'm not mistaken, at the transformer the grounded conductor is tapped onto the secondary windings and is also bonded to a GEC at the pole. Correct?
This should provide a solid reference point for the grounding conductor as well as providing a voltage reference for the transformer. Also correct?
In the event that the service relied soley on the GEC at the transformer there might be enough of an impedance on the grounded conductor back to the transformer to allow a small voltaic potential to exist between the equipment grounding conductor at the building and the earth itself, potentially creating a hazard? And the elimination of that potential is one of the functions of the second ground rod?
Thanks.
-John
I thought that was one of the basic ideas behind having a ground rod at the service entrance at all. I know they are used to dissipate a HV fault from whatever source, but I also thought they were there to provide a reference voltage to ground:
If I'm not mistaken, at the transformer the grounded conductor is tapped onto the secondary windings and is also bonded to a GEC at the pole. Correct?
This should provide a solid reference point for the grounding conductor as well as providing a voltage reference for the transformer. Also correct?
In the event that the service relied soley on the GEC at the transformer there might be enough of an impedance on the grounded conductor back to the transformer to allow a small voltaic potential to exist between the equipment grounding conductor at the building and the earth itself, potentially creating a hazard? And the elimination of that potential is one of the functions of the second ground rod?
Thanks.
-John
- Location
- Illinois
- Occupation
- retired electrician
Re: Portable Generators and Ground Rods
big john,
The only way that grounding electrodes could provide an equal potential would be if the earth had a very very low impedance. There will be a voltage between two electrodes that are bonded to the grounded conductor at 2 different locations equal to the voltage drop on that grounded conductor. Under normal operating conditions this should only be a few volts, but under fault conditions, this voltage can be much higher. Look at the picture on page that Roger posted on page 8 of this thread.
Don
big john,
The only way that grounding electrodes could provide an equal potential would be if the earth had a very very low impedance. There will be a voltage between two electrodes that are bonded to the grounded conductor at 2 different locations equal to the voltage drop on that grounded conductor. Under normal operating conditions this should only be a few volts, but under fault conditions, this voltage can be much higher. Look at the picture on page that Roger posted on page 8 of this thread.
Don
big john
Senior Member
- Location
- Portland, ME
Re: Portable Generators and Ground Rods
I also understand the grounding electrodes are not an effective fault return path, I was assuming that the grounded conductor was still in tact, just with only one electrode at the transformer.
What I'm trying to pin down is this:
Suppose we lived in a world with no lighting, no high voltage faults, no potential for electrostatic buildup. Suppose all that was eliminated: Would the second ground rod [the first rod being at the transformer] located at the service entrance to a building still be necessary?
I'm trying to figure out if this second electrode actually does serve some legitimate function other than the HV dissipation I listed above.
Thanks again.
-John
I understand that the situation I laid out should never occur, I just forgot to say it was purely hypothetical.
I also understand the grounding electrodes are not an effective fault return path, I was assuming that the grounded conductor was still in tact, just with only one electrode at the transformer.
What I'm trying to pin down is this:
Suppose we lived in a world with no lighting, no high voltage faults, no potential for electrostatic buildup. Suppose all that was eliminated: Would the second ground rod [the first rod being at the transformer] located at the service entrance to a building still be necessary?
I'm trying to figure out if this second electrode actually does serve some legitimate function other than the HV dissipation I listed above.
Thanks again.
-John
Re: Portable Generators and Ground Rods
1. Planned discharge path for lightning.
2. Accidental contact with HV & MV.
3. Stabilize system voltages with respect to earth.
4. Minimize touch potentials
5. Planned static discharge path.
You eliminated three, whats left?
No problem. The five reasons for an electrode in priority are:
1. Planned discharge path for lightning.
2. Accidental contact with HV & MV.
3. Stabilize system voltages with respect to earth.
4. Minimize touch potentials
5. Planned static discharge path.
You eliminated three, whats left?
big john
Senior Member
- Location
- Portland, ME
Re: Portable Generators and Ground Rods
Alight, this is either a testimant to the shortcomings of the English language or my inability to articulate myself.
That was, in fact, the whole point of my initiall question: I was trying to find out if the grounding electrode actually did "stabilize system voltage" and "minimize touch potentials." I suppose I should've just asked that in so many words, I guess I was just trying to get a picture of how it did that.
Thanks.
-John
Alight, this is either a testimant to the shortcomings of the English language or my inability to articulate myself.
That was, in fact, the whole point of my initiall question: I was trying to find out if the grounding electrode actually did "stabilize system voltage" and "minimize touch potentials." I suppose I should've just asked that in so many words, I guess I was just trying to get a picture of how it did that.
Thanks.
-John
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Portable Generators and Ground Rods
Dereck:
as the only way to minimize touch potential is to remove the voltage, and a ground rod does this very poorly. only if it could trip a breaker could it do this. but we know it can't.
If anything it will cause touch potential.
Dereck:
I'm curyous as how it does this too?
as the only way to minimize touch potential is to remove the voltage, and a ground rod does this very poorly. only if it could trip a breaker could it do this. but we know it can't.
If anything it will cause touch potential.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Portable Generators and Ground Rods
Derrick
One thing I was taught was that one of the reason's we cant eliminate the earth grounding is because of the solar flare storms from the sun. as it imposes high current on all the transmission lines and the earth grounding helps stabilize them. Of course It could be wrong.
Derrick
One thing I was taught was that one of the reason's we cant eliminate the earth grounding is because of the solar flare storms from the sun. as it imposes high current on all the transmission lines and the earth grounding helps stabilize them. Of course It could be wrong.
Re: Portable Generators and Ground Rods
The "touch potential" is under normal operating conditions. Under normal conditions there is no or very little current between two points, therefore even the high impedance can "minimize touch potential".. Fault conditions no way. However the EGC's, bonding jumpers, etc minimize touch potential under fault conditions on the equipment. I should of clarified that.
For voltage stabilization lets consider a large ungrounded system where circuit conductors are long and exhibit inductance and capacitance to ground. Under transient conditions the capacitance and inductance can resonate causing very high voltages across theinsulation and loads. (Sometimes, immediate damage is caused. And in all other cases, lifetime is decreased by the added stress) Now if purposely ground the system, the leakage capacitor is shorted, nullifying the effects.
Is that better?
The "touch potential" is under normal operating conditions. Under normal conditions there is no or very little current between two points, therefore even the high impedance can "minimize touch potential".. Fault conditions no way. However the EGC's, bonding jumpers, etc minimize touch potential under fault conditions on the equipment. I should of clarified that.
For voltage stabilization lets consider a large ungrounded system where circuit conductors are long and exhibit inductance and capacitance to ground. Under transient conditions the capacitance and inductance can resonate causing very high voltages across theinsulation and loads. (Sometimes, immediate damage is caused. And in all other cases, lifetime is decreased by the added stress) Now if purposely ground the system, the leakage capacitor is shorted, nullifying the effects.
Is that better?
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Portable Generators and Ground Rods
Ok
Now it makes some sense. So the lines would hold a charge simuilar to static charge.
And I agree with just a load type voltage drop it would be of some effect, as the voltages are low, but as said before with a lost neutral it wouldn't .
Ok
Now it makes some sense. So the lines would hold a charge simuilar to static charge.
And I agree with just a load type voltage drop it would be of some effect, as the voltages are low, but as said before with a lost neutral it wouldn't .
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: Portable Generators and Ground Rods
karl riley
Senior Member
Re: Portable Generators and Ground Rods
John, your question was very perceptive. Do you need the grounding electrode at the house, since it is at the Tformer?
Well, in the UK for most installations there is no electrode at the building, only at the Tformer.
And here's another eye-opener: In Ireland you are not allowed to use the water pipe as a grounding electrode!
Karl
John, your question was very perceptive. Do you need the grounding electrode at the house, since it is at the Tformer?
Well, in the UK for most installations there is no electrode at the building, only at the Tformer.
And here's another eye-opener: In Ireland you are not allowed to use the water pipe as a grounding electrode!
Karl
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