Grounding wooden poles

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hardworkingstiff said:
I'm not trying to correct anyone, just become more knowledgeable. I also would like to thank you for posting the information. It clearly shows there are better grounding methods than what we typically use.
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You were correct none the less ,.. and you are welcome , I see we are both here for the same reason..:)
 
iwire said:
To me the question becomes do we need 'better electrodes'?.....
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I would think it depends as to what level one is trying to protect,.. does he (op) really need to use that braided lightning cable ???

I have never really done lighting protection,.. but to me it sounded as if that was what he was talking about so I would think as close to zero would be part of what provides for good protection ,... his idea ,...not so good (no offense meant)
 
Pierre C Belarge said:
I appreciate what Gary did, he really worked hard in providing us with his experiment. I am curious how practical it really is.

In regards to your comment about shock hazard, is that the reason behind installing electrodes and the grounding electrode system?[/QUOTE]

It is one the biggest myths that surround the grounding electrode system, and it is why it is so blown out of proportion, because of the mis-understanding of what bonding to Earth can really do.

The problem here is not many understand, the results that we find in Gary's experiment, they lean toward the myth, that a lower resistance of an electrode will open a OCPD, but they miss that not all circuits are low current(15/20amp) and that the earth can not be depended upon to consistency open a breaker.
So this only leaves the other reason of requirement, lowering the voltage to earth, as in touch potential, and we can now see (because of Gary's experiment) that the better the conductivity of Earth, the higher the touch potential.

Now for the NEC requirements for an electrode:
To limit voltages of a higher source?
we know the voltage drop across a given resistance will be the same at a given current, so if I have a 25 ohm rod that will produce a 90 volt potential at 3' from the rod, it will not matter if the source is at 120 volts or 7200 volts, you will still have a touch hazard. will the 7200 volt OCPD open? in most cases it should, but I have posted one such case it didn't, even with 4 rods, and still did a lot of damage to the house and the equipment in it, and if there was any contact of a person to anything grounded in those two houses, they would have been dead, or close to it.

Ground rods do nothing in an NEC building to make a building safe from shock or fire, period!;)
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hurk27 said:
Pierre C Belarge said:
I appreciate what Gary did, he really worked hard in providing us with his experiment. I am curious how practical it really is.

In regards to your comment about shock hazard, is that the reason behind installing electrodes and the grounding electrode system?[/QUOTE]

It is one the biggest myths that surround the grounding electrode system, and it is why it is so blown out of proportion, because of the mis-understanding of what bonding to Earth can really do.

The problem here is not many understand, the results that we find in Gary's experiment, they lean toward the myth, that a lower resistance of an electrode will open a OCPD, but they miss that not all circuits are low current(15/20amp) and that the earth can not be depended upon to consistency open a breaker.
So this only leaves the other reason of requirement, lowering the voltage to earth, as in touch potential, and we can now see (because of Gary's experiment) that the better the conductivity of Earth, the higher the touch potential.

Now for the NEC requirements for an electrode:
To limit voltages of a higher source?
we know the voltage drop across a given resistance will be the same at a given current, so if I have a 25 ohm rod that will produce a 90 volt potential at 3' from the rod, it will not matter if the source is at 120 volts or 7200 volts, you will still have a touch hazard. will the 7200 volt OCPD open? in most cases it should, but I have posted one such case it didn't, even with 4 rods, and still did a lot of damage to the house and the equipment in it, and if there was any contact of a person to anything grounded in those two houses, they would have been dead, or close to it.

Ground rods do nothing in an NEC building to make a building safe from shock or fire, period!;)
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Wayne
I am not sure, but I do not believe you and I are on a different page, maybe just stating it differently.

I will say that limiting the voltage does not mean eliminating it. There are times the electrode system will help when the higher voltages are introduced to a building, and other times it will not. I am not an expert in explaining or understanding why. I will say I believe it mostly has to do with the resistance introduced due to soil conditions and distance to the utility protection.
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hurk27 said:
we see that basically as the conductivity of Earth increases, the sphere of influence decreases, and this can increase the shock hazard, as higher voltages will be available closer surrounding the electrode, so touch potential, is increased. so instead of 90 volts at the 3 foot mark, you might have 105 volts.
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Of course different resistance numbers change the results but 90 volts can kill me just as well as 105.

My point being is electrodes can not be expected to save my butt.



so over all, it would be in my opinion that even having a better electrode, as far as an NEC requirement, would lead to a higher potential of touch and shock hazard, and is probably one of the best reasons to get rid of the requirements for grounding rods, and some of the other electrodes.
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Is that what we install rods for?

Are we allowed to use the earth for a bonding path?

How many times have you gone into an old home or building and found no earth grounding?

Has there been a pile of bodies around the building?

Sometimes I think we struggle to fix what is not broken. :)
 
Pierre C Belarge said:
hurk27 said:
Wayne
I am not sure, but I do not believe you and I are on a different page, maybe just stating it differently.

I will say that limiting the voltage does not mean eliminating it. There are times the electrode system will help when the higher voltages are introduced to a building, and other times it will not. I am not an expert in explaining or understanding why. I will say I believe it mostly has to do with the resistance introduced due to soil conditions and distance to the utility protection.
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I think were close to being on the same page, just the issue with the voltage limiting factor of a electrode.

Only if the electrode can open the OCPD can it protect a building.

The problem with the thinking that the electrode will limit the voltage on a building, is, that almost all the voltage drop will be across the electrode, not on the conductors from the source.

it the case of the two houses I had encountered, the amount of damage, clearly showed that almost all the 7200 volts was present in the building and electrical system, and the burn marks around the electrode indicated that almost all the voltage drop dropped across the Earth surrounding the electrode. this left the building at close to the full 7200 volts because of the low impedance path it came into the building on (the service neutral)

if we were to place a 120 volt on the building that had no other low impedance reference to the X0 of the source, other than the ground rod, this building will be at 120 volts to Earth, all the voltage will be dropped in a very short distance around the electrode, not evenly across the wiring in a building or the conductors running out to the pole. so because of this, the building will have almost the full potential of the circuit feeding it, as the resistance of the conductors feeding the building are much lower in resistance than the resistance of the electrode.

Its simple math, of two series resistors, one the low resistance of the conductors, and the other the high resistance of the electrode.

So the bottom line is, if the OCPD does not open, the voltage will be present on all the grounding of the building.
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hurk27 said:
Pierre C Belarge said:
I think were close to being on the same page, just the issue with the voltage limiting factor of a electrode.

Only if the electrode can open the OCPD can it protect a building.

The problem with the thinking that the electrode will limit the voltage on a building, is, that almost all the voltage drop will be across the electrode, not on the conductors from the source.

it the case of the two houses I had encountered, the amount of damage, clearly showed that almost all the 7200 volts was present in the building and electrical system, and the burn marks around the electrode indicated that almost all the voltage drop dropped across the Earth surrounding the electrode. this left the building at close to the full 7200 volts because of the low impedance path it came into the building on (the service neutral)

if we were to place a 120 volt on the building that had no other low impedance reference to the X0 of the source, other that the ground rod, this building will be at 120 volts to Earth, all the voltage will be dropped in a very short distance around the electrode, not evenly across the wiring in a building or the conductors running out to the pole. so because of this, the building will have almost the full potential of the circuit feeding it, as the resistance of the conductors feeding the building are much lower in resistance than the resistance of the electrode.

So the bottom line is, if the OCPD does not open, the voltage will be present on all the grounding of the building.[/quote]




Wayne
I do not see this as a grounding issue related to the grounding electrode system (250.4(A)(1)&(2). I see it as a bonding issue (250.4(A)(3)&(5).
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So the bottom line is, if the OCPD does not open, the voltage will be present on all the grounding of the building.[/quote]




Wayne
I do not see this as a grounding issue related to the grounding electrode system (250.4(A)(1)&(2). I see it as a bonding issue (250.4(A)(3)&(5).
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How is it a bonding issue, when we are talking about electrodes and what purpose they serve, bonding issues would only cover circuits that have a return to source path of low impedance, and electrode will only have the path through Earth back to source. and on of the reasons the NEC say it is for, is to limit voltages of a higher source. All I was showing is it can't even preform this because of what I said in my previous post?

If we have a bonding path would an electrode be even needed? no, so why would an electrode even help with a bonded path such as a city common water supply. it would not do anything to increase the safety. and if there is no common water water supply pipe, the electrode will not even limit the voltage of a higher source.

I was just trying to show that most of the required electrodes serve no purpose in the NEC. the science is not there to back their requirement.
 
M. D. said:
was't the op concerned about damage caused by lightning??
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hurk27 said:
um errr well yes, But I thought that was summarized pretty well in the first response:confused:

Do you know of a way to guarantee protection against a direct lightning strike?

If you do I'm all ears;)
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What I was getting at, is this, if you were to go and buy a car, that claimed 30-40 MPG, and after you drove it a little, you find it only gets 4-6 MPG, you would be all over that dealer.

this is about how it would be if we were to try to tell a customer electrodes will protect his equipment from a lightning strike, and after the first incident that customer will be all over us.;)

We would be no more better then the company's out there selling snake oil PF correction caps, saying it will save you on your electric bill.

And for it to be a requirement in the NEC:mad:
wounder how far the NEC would get requiring PF correction caps.:cool:
 
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OK let me see if I understand ,... Lightning protection systems are rabbit crap,.. is that pretty much your opinion?
 
M. D. said:
OK let me see if I understand ,... Lightning protection systems are rabbit crap,.. is that pretty much your opinion?
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Err nope, we were talking about what the NEC imply there required electrode systems are for. not Lightning protection systems.

sure a properly installed Lightning protection system installed by a UL certified Lightning protection system specialist, can contribute to the reduction of damage caused by lightning, but this is a whole nother ball game from the electrode requirements of the NEC, and even then, a properly install LPS will not fully guarantee total protection.

Having the understanding of the limits of what something can do or not, can go along way in determining how much money one should spend, trying to do something that cant be accomplished with just a few ground rods.

NFPA 780 installed systems are not cheap.
 
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