pole bases once and for all
- Thread starter captainkevin
- Start date
- Status
Ed MacLaren
Senior Member
Re: pole bases once and for all
Bryan, your idea makes sense to me too, with regard to a relatively non-conductive structure, like a building.
Ed
Bryan, your idea makes sense to me too, with regard to a relatively non-conductive structure, like a building.
Ed
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: pole bases once and for all
I think the one thing that most don't understand is the fact that lightning is a dc current that has ac properties. and if any one understands radio theory you know that for a radio transmitter to function the signal has to go into a metal antenna that is at the correct resonance of the frequency of the transmitter. now with that said here's another point: with RF energy what would be a short to DC current can be an open to RF and what is an open to DC can be a short to RF. now lets look at lightning since it does have a fast rise time that can very from strike to strike there is no sure fire system that can shunt all strikes to ground or that would be the best broad banded antenna ever made. when I was in Florida I have seen lightning strike a 30' tree and leave a 150' metal tower alone that was only feet from the tree, so when lightning gets ready to strike it will depend on the resonant frequency of the lightning to what it is going to see as a resonant target to strike.
And the best grounded system in the world will not stop it. As for TVSS systems they are just play toys for the power in a lightning strike and will just go
poof with a direct hit.
I think the one thing that most don't understand is the fact that lightning is a dc current that has ac properties. and if any one understands radio theory you know that for a radio transmitter to function the signal has to go into a metal antenna that is at the correct resonance of the frequency of the transmitter. now with that said here's another point: with RF energy what would be a short to DC current can be an open to RF and what is an open to DC can be a short to RF. now lets look at lightning since it does have a fast rise time that can very from strike to strike there is no sure fire system that can shunt all strikes to ground or that would be the best broad banded antenna ever made. when I was in Florida I have seen lightning strike a 30' tree and leave a 150' metal tower alone that was only feet from the tree, so when lightning gets ready to strike it will depend on the resonant frequency of the lightning to what it is going to see as a resonant target to strike.
And the best grounded system in the world will not stop it. As for TVSS systems they are just play toys for the power in a lightning strike and will just go
poof with a direct hit.
- Location
- Illinois
- Occupation
- retired electrician
Re: pole bases once and for all
Bennie,
Don
Bennie,
You're right, the code words do not require the fault to be cleared, only that the fault return path be able to safely handle the fault current.
Don
charlie
Senior Member
- Location
- Indianapolis
Re: pole bases once and for all
Charlie, I read them both some time ago. And as a result I still practice NFPA 780 with the rcommended changes of using blunt tipped air terminals and TVSS devices.
It appears the "Bryan Panel" was influenced by sales personnel. The last two paragraphs sums up the whole article.
Charlie, I read them both some time ago. And as a result I still practice NFPA 780 with the rcommended changes of using blunt tipped air terminals and TVSS devices.
It appears the "Bryan Panel" was influenced by sales personnel. The last two paragraphs sums up the whole article.
bphgravity
Senior Member
- Location
- Florida
Re: pole bases once and for all
Is there any absolute positive guarantee that AFCI's will prevent every arc that could ignite a fire? Is there any absolute positive guarantee that a GFCI will prevent the shock or electrocution of a person? Is there any absolute guarantee that a surge arrestor or TVSS will prevent the damage of equipment due to transient currents? Just because something isn't a guarantee to always work or always protect, it doesn't mean the idea should be totally dismissed. I don't think a lightning protection system should be a mandatory requirement, but it shouldn't also be discredited because of lack of scientific evidence. It certainly doesn't harm an installation. The world was flat and at the center of the universe at one time because of lack of scientific evidence. What if everyone gave up on the idea that it might just be round and in a remote corner of the universe? Until the science is perfect, might as well do whatever can and may work. Just my opinion.
Is there any absolute positive guarantee that AFCI's will prevent every arc that could ignite a fire? Is there any absolute positive guarantee that a GFCI will prevent the shock or electrocution of a person? Is there any absolute guarantee that a surge arrestor or TVSS will prevent the damage of equipment due to transient currents? Just because something isn't a guarantee to always work or always protect, it doesn't mean the idea should be totally dismissed. I don't think a lightning protection system should be a mandatory requirement, but it shouldn't also be discredited because of lack of scientific evidence. It certainly doesn't harm an installation. The world was flat and at the center of the universe at one time because of lack of scientific evidence. What if everyone gave up on the idea that it might just be round and in a remote corner of the universe? Until the science is perfect, might as well do whatever can and may work. Just my opinion.
Re: pole bases once and for all
Sounds like everyone is on the same page as far as the 'lowly ground-rod' is concerned.
The ground-rod proliferation seems to be have something to do with the utilities, I cant prove it, but have been doing some searching on Stray-Voltage, and alot of people have referenced this as one of the causes, along with the fact, that the utilities tie the neutrals together(primary and neutral)
As far as the light pole goes, as Don said, why wouldnt the supporting structure for the pole serve as well as a ground rod.
IF the GR is protecting the 'pole' what exactly is it suppose to be protecting, the metal pole or the fixture.?
sparkyoh
Sounds like everyone is on the same page as far as the 'lowly ground-rod' is concerned.
The ground-rod proliferation seems to be have something to do with the utilities, I cant prove it, but have been doing some searching on Stray-Voltage, and alot of people have referenced this as one of the causes, along with the fact, that the utilities tie the neutrals together(primary and neutral)
As far as the light pole goes, as Don said, why wouldnt the supporting structure for the pole serve as well as a ground rod.
IF the GR is protecting the 'pole' what exactly is it suppose to be protecting, the metal pole or the fixture.?
sparkyoh
charlie
Senior Member
- Location
- Indianapolis
Re: pole bases once and for all
If the supporting structure went down as far as a ground rod, you statement would make sense. If the foundation were able to take a 20 foot piece of rebar, laid out horizontally like a Ufer, again the ground rod would be superfluous. The reality is that the ground rods at all of the columns are protecting the building's electrical system. By reducing the voltage and energy levels, the system may be able to handle the remaining power surge.
OK Sparkyoh, the ground rod proliferation is required by the NESC, not the utilities. Also, to be in compliance with the NESC, the utilities are required to bond the neutrals together on the poles. In fact, you are required to bond the neutrals of your SDS together through the GEC. I do concede that some of the representation on the panels is from the electric utilities; however, you will find the same makeup on the NEC panels.
If the supporting structure went down as far as a ground rod, you statement would make sense. If the foundation were able to take a 20 foot piece of rebar, laid out horizontally like a Ufer, again the ground rod would be superfluous. The reality is that the ground rods at all of the columns are protecting the building's electrical system. By reducing the voltage and energy levels, the system may be able to handle the remaining power surge.
- Location
- Illinois
- Occupation
- retired electrician
Re: pole bases once and for all
Bennie,
Don
Bennie,
Very, very few ground rods have a low enough inpedance to play any part in clearing a fault on a low voltage system.
Don
Re: pole bases once and for all
Parallel paths share a part in clearing ground faults. The total resistance decreases with an increase in paths.
The earth alone can not clear a fault, but will aid in clearing.
The low voltage, to ground, in the US needs all the help it can get.
Parallel paths share a part in clearing ground faults. The total resistance decreases with an increase in paths.
The earth alone can not clear a fault, but will aid in clearing.
The low voltage, to ground, in the US needs all the help it can get.
Re: pole bases once and for all
250.4(A)(5)...The earth shall not be used as the sole equipment grounding conductor or effective ground fault current path.
This implies that the earth shall be used when it is not the sole equipment ground conductor or effective ground fault path.
250.4(A)(5)...The earth shall not be used as the sole equipment grounding conductor or effective ground fault current path.
This implies that the earth shall be used when it is not the sole equipment ground conductor or effective ground fault path.
- Status