lighiting poles ground rod
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ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: lighiting poles ground rod
Many people will tell you that a ground rod at a lighting pole serves no real purpose. I happen to agree.
Many people will tell you that a ground rod at a lighting pole serves no real purpose. I happen to agree.
jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: lighiting poles ground rod
Depends on what you exspect from them.They will not help with a ground fault.They will help with a lightning strike.I am installing several right now in a ball park.Musco has it in there specs to have a rod and #2 to a bonding lug inside the pole.Considering they are 58 feet in the air and this being the lightning capital i think its worth the cost to try to save them.
Depends on what you exspect from them.They will not help with a ground fault.They will help with a lightning strike.I am installing several right now in a ball park.Musco has it in there specs to have a rod and #2 to a bonding lug inside the pole.Considering they are 58 feet in the air and this being the lightning capital i think its worth the cost to try to save them.
- Location
- Massachusetts
Re: lighiting poles ground rod
How is a lowly ground rod going to be any better than that?
Considering they are 58 feet in the air I imagine they are bolted to a large block of concrete already in intimate contact with the earth.
How is a lowly ground rod going to be any better than that?
jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: lighiting poles ground rod
"Considering they are 58 feet in the air I imagine they are bolted to a large block of concrete already in intimate contact with the earth."
Think about it Bob,concrete is not exactly a great conductor and if the pole got a direct hit would it not be better to try to let a rod take it than exsplode the concrete.
And they are not bolted.The concrete is a round piece hollow in the center,pole slides over it
http://www.musco.com/
[ July 26, 2005, 08:08 PM: Message edited by: jimwalker ]
"Considering they are 58 feet in the air I imagine they are bolted to a large block of concrete already in intimate contact with the earth."
Think about it Bob,concrete is not exactly a great conductor and if the pole got a direct hit would it not be better to try to let a rod take it than exsplode the concrete.
And they are not bolted.The concrete is a round piece hollow in the center,pole slides over it
http://www.musco.com/
[ July 26, 2005, 08:08 PM: Message edited by: jimwalker ]
friebel
Senior Member
- Location
- Pennsville, N.J.
Re: lighiting poles ground rod
If it was I installing the lighting poles that you have described, I would have the at least 20 feet of 1/2 inch steel reinforcing rod in the concrete. Number one, it will give strength to the concrete, and number two, it will be a good, if not a better ground for lightning protection, and high voltages surges, not for ground fault protection. That is what the Equipment grounding conductor is for, that you have going back to the panel from where you are feeding the lights You could also install the 8 foot driven ground rod if you want too.
If it was I installing the lighting poles that you have described, I would have the at least 20 feet of 1/2 inch steel reinforcing rod in the concrete. Number one, it will give strength to the concrete, and number two, it will be a good, if not a better ground for lightning protection, and high voltages surges, not for ground fault protection. That is what the Equipment grounding conductor is for, that you have going back to the panel from where you are feeding the lights You could also install the 8 foot driven ground rod if you want too.
- Location
- Massachusetts
Re: lighiting poles ground rod
Uffers are generally considered far better than a rod.
So when the lightning strike comes the lightning current will 'know' to go out the ground rod and not out the concrete base with it's lower resistance.
How is this accomplished, is a warning sign placed at the pole grounding lug directing the lightning which way to go?
Someone better explain that to uffer.
Uffers are generally considered far better than a rod.
So when the lightning strike comes the lightning current will 'know' to go out the ground rod and not out the concrete base with it's lower resistance.
How is this accomplished, is a warning sign placed at the pole grounding lug directing the lightning which way to go?
bphgravity
Senior Member
- Location
- Florida
Re: lighiting poles ground rod
I did alot of work at the Texas Rangers field here in Port Charlotte and a few times I got to go up the light poles. There were several incidents of lightning blowing out a few lamps and components, and these poles were all connected to a ground rod at the base. Of the four outfield poles, three had been struck or at least effected by lightning. The fourth, as far as anyone could ever tell or could report, never did get struck. The funny thing is, that's the pole that had a huge Osprey nest on it. Maybe the birds know something we don't!
I did alot of work at the Texas Rangers field here in Port Charlotte and a few times I got to go up the light poles. There were several incidents of lightning blowing out a few lamps and components, and these poles were all connected to a ground rod at the base. Of the four outfield poles, three had been struck or at least effected by lightning. The fourth, as far as anyone could ever tell or could report, never did get struck. The funny thing is, that's the pole that had a huge Osprey nest on it. Maybe the birds know something we don't!
kentirwin
Senior Member
- Location
- Norfolk, VA
Re: lighiting poles ground rod
The industrial site where I work has probably 75 pole lights. Five of them were erected where bollards wer originally installed. These 5 poles all have ground rods. These 5 are the ONLY ones on the property that routinely have their components blown out by lightning. Coincidence?
The industrial site where I work has probably 75 pole lights. Five of them were erected where bollards wer originally installed. These 5 poles all have ground rods. These 5 are the ONLY ones on the property that routinely have their components blown out by lightning. Coincidence?
jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: lighiting poles ground rod
"The industrial site where I work has probably 75 pole lights. Five of them were erected where bollards wer originally installed. These 5 poles all have ground rods. These 5 are the ONLY ones on the property that routinely have their components blown out by lightning. Coincidence? "
Are you suggesting we might be safer without them ? I know years ago it was common to see lightning rods on barns.Perhaps they do more damage than good.
As to the ones we put in,there is no choice.They are part of the specs.I would assume the concrete bases do have some reinforcement rods but they are not exsposed to use.I do know if one gets hit and falls i don't want to be near it.
"The industrial site where I work has probably 75 pole lights. Five of them were erected where bollards wer originally installed. These 5 poles all have ground rods. These 5 are the ONLY ones on the property that routinely have their components blown out by lightning. Coincidence? "
Are you suggesting we might be safer without them ? I know years ago it was common to see lightning rods on barns.Perhaps they do more damage than good.
As to the ones we put in,there is no choice.They are part of the specs.I would assume the concrete bases do have some reinforcement rods but they are not exsposed to use.I do know if one gets hit and falls i don't want to be near it.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Re: lighiting poles ground rod
I have often wondered about that myself.
Seems like you are just asking for trouble by putting up a lightning rod.
Lightning tends to go where it wants to, regardless of how you try to channel it elsewhere.
Putting up a rod to attract it seems somehow like a bad idea when you think of it that way.
In reality, you cannot prevent damage from lightning (at least not economically). You can take economical steps to reduce your risk though.
I have often wondered about that myself.
Seems like you are just asking for trouble by putting up a lightning rod.
Lightning tends to go where it wants to, regardless of how you try to channel it elsewhere.
Putting up a rod to attract it seems somehow like a bad idea when you think of it that way.
In reality, you cannot prevent damage from lightning (at least not economically). You can take economical steps to reduce your risk though.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Re: lighiting poles ground rod
I don't know much about lightning protection but I thought that the use of air terminals (lightning rods) was to prevent lightning by changing the charge on the top of the object. I don't think that the purpose is to attract lightning.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Re: lighiting poles ground rod
Actually, the tip of the rod streams electrons into the air; the sharper the tip, the better it works.
Re: lighiting poles ground rod
thank you every much Ryan, i frankly didn't expect this kind of response, hey Ryan what kind of work do you guys do up there. Down here(Florida) we got plenty of commercial and residential, but not too much of industrial, i was wondering, because I've always feel interested for your city but I'm not sure if there is enough work for another electrician. thanks for any comment on that.
thank you every much Ryan, i frankly didn't expect this kind of response, hey Ryan what kind of work do you guys do up there. Down here(Florida) we got plenty of commercial and residential, but not too much of industrial, i was wondering, because I've always feel interested for your city but I'm not sure if there is enough work for another electrician. thanks for any comment on that.
- Location
- Massachusetts
Re: lighiting poles ground rod
Two reasons
1)The NEC description "within and near the bottom of a concrete foundation or footing" does not match a slab.
2)The NEC description "direct contact with the earth" does not match with concrete isolated by a poly vapor barrier.
Take a look at part of 250.52(A)(3)
Justin, IMO what you describe is not a NEC 'uffer".
Two reasons
1)The NEC description "within and near the bottom of a concrete foundation or footing" does not match a slab.
2)The NEC description "direct contact with the earth" does not match with concrete isolated by a poly vapor barrier.
Re: lighiting poles ground rod
If a pole takes a direct lightning strike, it will be damaged regardless of the type of grounding that is installed. It is not reasonable to think that all of the energy of a direct lightning strike will be dissipated by a #6 wire and a ground rod. That said, the reinforcing steel in the concrete base is probably a much better ground than any ground rod could ever hope to be. The main thing is that, no matter how well the pole is grounded, there MUST still be an equipment grounding conductor run to the pole with the circuit conductors to safely carry any fault current and cause the overcurrent device to operate. No amount of earth grounding can take the place of this conductor. So drive ground rods if it lets you sleep better at night, or rely on the "ufer" ground in the pole base but ALWAYS run an equipment grounding conductor!
If a pole takes a direct lightning strike, it will be damaged regardless of the type of grounding that is installed. It is not reasonable to think that all of the energy of a direct lightning strike will be dissipated by a #6 wire and a ground rod. That said, the reinforcing steel in the concrete base is probably a much better ground than any ground rod could ever hope to be. The main thing is that, no matter how well the pole is grounded, there MUST still be an equipment grounding conductor run to the pole with the circuit conductors to safely carry any fault current and cause the overcurrent device to operate. No amount of earth grounding can take the place of this conductor. So drive ground rods if it lets you sleep better at night, or rely on the "ufer" ground in the pole base but ALWAYS run an equipment grounding conductor!
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: lighiting poles ground rod
Amen to that!
Re: lighiting poles ground rod
A quote from Bennie,
Lightning rods are electron suckers,they pull the excess of electrons out of thesurrounding atmosphere and dump into the earth. This prevents a high static voltage from developing to a flashover stage.
Lightning (protection) prevention is a shorting effect between the oppisite charges.
c.c.frank
A quote from Bennie,
Lightning rods are electron suckers,they pull the excess of electrons out of thesurrounding atmosphere and dump into the earth. This prevents a high static voltage from developing to a flashover stage.
Lightning (protection) prevention is a shorting effect between the oppisite charges.
c.c.frank
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