Parking lot light pole ground rod
- Thread starter earthman
- Start date
- Status
- Location
- Illinois
- Occupation
- retired electrician
Re: Parking lot light pole ground rod
There is no code requirement for a grounding electrode at a light pole. There is a requirement that that circuit feeding the pole have an EGC.
Don
There is no code requirement for a grounding electrode at a light pole. There is a requirement that that circuit feeding the pole have an EGC.
Don
pierre
Senior Member
- Location
- Westchester County, New York
Re: Parking lot light pole ground rod
IMHO the ground rod at a lighting pole serves no purpose but to waste money and time. The ground rod will not protect the lighting equipment from lightning, and it will not aid in keeping the concrete footing from breaking apart during a direct lightning hit. Sometimes in this industry we 'over ground' and I firmly believe this is one time. The concrete plug that serves to support the lighting fixture is a good connection to the earth, therefore negating the need for the ground rod.
Pierre
IMHO the ground rod at a lighting pole serves no purpose but to waste money and time. The ground rod will not protect the lighting equipment from lightning, and it will not aid in keeping the concrete footing from breaking apart during a direct lightning hit. Sometimes in this industry we 'over ground' and I firmly believe this is one time. The concrete plug that serves to support the lighting fixture is a good connection to the earth, therefore negating the need for the ground rod.
Pierre
charlie
Senior Member
- Location
- Indianapolis
Re: Parking lot light pole ground rod
Pierre, I would agree except most concrete bases don't go deep enough . . . HMMM . . . to do the intended job and would not be down to the moist earth.
Re: Parking lot light pole ground rod
The earth is a conductive material. Any conductive material will carry fault current based on the impedance.
The impedance, of the earth, may not permit an internal logic overcurrent device to operate. It will permit a proportional sensor device to function.
All possible fault paths should be used, on long runs of wire and cable. Each one will reduce the total impedance.
A rod should be driven into the moisture, and related salt content if possible. Spacing numerous rods do not make much change in impedance. Driving them deeper does make a difference. How many tests, do you hear, being performed on variation of depth?
The earth is a conductive material. Any conductive material will carry fault current based on the impedance.
The impedance, of the earth, may not permit an internal logic overcurrent device to operate. It will permit a proportional sensor device to function.
All possible fault paths should be used, on long runs of wire and cable. Each one will reduce the total impedance.
A rod should be driven into the moisture, and related salt content if possible. Spacing numerous rods do not make much change in impedance. Driving them deeper does make a difference. How many tests, do you hear, being performed on variation of depth?
Re: Parking lot light pole ground rod
It was once explained to me by an inspector that the AHJ considered the light pole base to be a "separate structure" and thus required its own grounding electode. When I asked about the single circuit exception and the requirements calling for a disconnect at the "separate structure" he said that he was real busy and had to go.
Now that I am an inspector, I only require an electrode at the pole base if it calls for one on the approved plans.
It was once explained to me by an inspector that the AHJ considered the light pole base to be a "separate structure" and thus required its own grounding electode. When I asked about the single circuit exception and the requirements calling for a disconnect at the "separate structure" he said that he was real busy and had to go.
Now that I am an inspector, I only require an electrode at the pole base if it calls for one on the approved plans.
- Location
- Illinois
- Occupation
- retired electrician
Re: Parking lot light pole ground rod
kqresq,
That is a valid point. A few code cycles ago Exception #3 to 225.32 was added to the code because a light pole is a structure and inspectors were requiring a disconnect at each pole. Most light poles are fed by a single branch circuit and the exception to 250.32(A) would delete the requirement for a grounding electrode at the pole.
Don
kqresq,
That is a valid point. A few code cycles ago Exception #3 to 225.32 was added to the code because a light pole is a structure and inspectors were requiring a disconnect at each pole. Most light poles are fed by a single branch circuit and the exception to 250.32(A) would delete the requirement for a grounding electrode at the pole.
Don
brian john
Senior Member
- Location
- Leesburg, VA
Re: Parking lot light pole ground rod
bennie:
Don't know if you ever visited this site, but I have included the link for your reference.
http://www.cpccorp.com/deep.htm
bennie:
Don't know if you ever visited this site, but I have included the link for your reference.
http://www.cpccorp.com/deep.htm
Re: Parking lot light pole ground rod
I know everyone on here knows this but I think that driving a rod at the pole had nothing to do with operating the overcurrent device under a fault condition but was for reducing the risk of getting electrocutied from touching the pole.
And I think in some cases where the base might not be a good enough conductor a ground rod would help.
Ronald :roll:
[ July 25, 2003, 06:03 PM: Message edited by: ronaldrc ]
I know everyone on here knows this but I think that driving a rod at the pole had nothing to do with operating the overcurrent device under a fault condition but was for reducing the risk of getting electrocutied from touching the pole.
And I think in some cases where the base might not be a good enough conductor a ground rod would help.
Ronald :roll:
[ July 25, 2003, 06:03 PM: Message edited by: ronaldrc ]
- Location
- Illinois
- Occupation
- retired electrician
Re: Parking lot light pole ground rod
Ron,
The use of a grounding electrode does very little to reduce the potential of a shock between an energized pole and the earth. This is because almost all of the voltage drop is with in a foot or so of the ground rod. A person touching the energized pole and standing on the ground a couple of feet from the ground rod will be subjected to 70% to 80% of the line to ground voltage.
Don
Ron,
The use of a grounding electrode does very little to reduce the potential of a shock between an energized pole and the earth. This is because almost all of the voltage drop is with in a foot or so of the ground rod. A person touching the energized pole and standing on the ground a couple of feet from the ground rod will be subjected to 70% to 80% of the line to ground voltage.
Don
Re: Parking lot light pole ground rod
Don I don't disagree I know there was a thread that went into this subject in detail but a ground rod would help a little theres a lot of variables and its hard to just say it helps very little when in fact it might save a life under certain conditions.
I'm not pushing to ground every metal pole thats on a concrete pad but I don't necessarily think its a waste of money.
Ronald
Don I don't disagree I know there was a thread that went into this subject in detail but a ground rod would help a little theres a lot of variables and its hard to just say it helps very little when in fact it might save a life under certain conditions.
I'm not pushing to ground every metal pole thats on a concrete pad but I don't necessarily think its a waste of money.
Ronald
Re: Parking lot light pole ground rod
Don, Really just wanted to make the point about not kicking the breaker,but let me say that a little bit different.If I where working for someone and they ask me to drive a ground and ground a metal light pole on a concrete base I would tell them it probably wouldn't do a lot of good.But if they they had the money I wouldn't argue with them.
Ronald
Don, Really just wanted to make the point about not kicking the breaker,but let me say that a little bit different.If I where working for someone and they ask me to drive a ground and ground a metal light pole on a concrete base I would tell them it probably wouldn't do a lot of good.But if they they had the money I wouldn't argue with them.
Ronald
- Location
- Illinois
- Occupation
- retired electrician
Re: Parking lot light pole ground rod
Ron,
I know it is a common practice, and I have installed ground rods at poles when they were called for on the plans. I just wanted to make sure that no one would rely on a ground rod for keeping people safe.
Don
Ron,
I know it is a common practice, and I have installed ground rods at poles when they were called for on the plans. I just wanted to make sure that no one would rely on a ground rod for keeping people safe.
Don
charlie
Senior Member
- Location
- Indianapolis
Re: Parking lot light pole ground rod
I agree that a ground rod would not be of any use for ground fault return. Assume a ground rod intalled at every column and one was struck by lightning. Would the lightning go back into the building or disipate into the earth? I contend that a portion would be disipated into the earth and some would still make it into the building on the grounding conductor. I also contend that more would be disipated with the ground rods at each column than without.
I agree that a ground rod would not be of any use for ground fault return. Assume a ground rod intalled at every column and one was struck by lightning. Would the lightning go back into the building or disipate into the earth? I contend that a portion would be disipated into the earth and some would still make it into the building on the grounding conductor. I also contend that more would be disipated with the ground rods at each column than without.
Re: Parking lot light pole ground rod
Charlie I agree that the ground rod would help at the pole as far as taking some of the energy of the lighthning bolt to ground.
But in these remote occurrencies is it worth it to ground every metal pole on a concrete base or a base of which is not that good of a conductor?
Evidently the NEC board memebers don't think so.
The 2002 NEC says just the equipment grounding conductor of the circuit is efficient or is all that is required.
Ronald
Charlie I agree that the ground rod would help at the pole as far as taking some of the energy of the lighthning bolt to ground.
But in these remote occurrencies is it worth it to ground every metal pole on a concrete base or a base of which is not that good of a conductor?
Evidently the NEC board memebers don't think so.
The 2002 NEC says just the equipment grounding conductor of the circuit is efficient or is all that is required.
Ronald
Re: Parking lot light pole ground rod
ANSI/IES RP8, covers Practice for Roadway lighting. This is, of course, in the NESC.
Each pole is required to have a 5/8" by 10' copperweld ground rod.
The NESC is created by the IEEE Standards. There must be scientific papers, to substantiate the requirement for a ground rod.
The fact this requirement is not in the NEC, should not be justification for ignoring the procedure.
ANSI/IES RP8, covers Practice for Roadway lighting. This is, of course, in the NESC.
Each pole is required to have a 5/8" by 10' copperweld ground rod.
The NESC is created by the IEEE Standards. There must be scientific papers, to substantiate the requirement for a ground rod.
The fact this requirement is not in the NEC, should not be justification for ignoring the procedure.
Re: Parking lot light pole ground rod
I Bennie how are you?
I take it you're in favor of driving the rod at the pole? Would this be every metal pole or just the ones on concrete bases Ect?
Ronald
[ July 26, 2003, 11:44 AM: Message edited by: ronaldrc ]
I Bennie how are you?
I take it you're in favor of driving the rod at the pole? Would this be every metal pole or just the ones on concrete bases Ect?
Ronald
[ July 26, 2003, 11:44 AM: Message edited by: ronaldrc ]
Re: Parking lot light pole ground rod
Ronald: A typical 20 foot light pole, will have a 5 foot base. The flange, on the pole, will bolt to the base. The combination of rust, and metal oxidation, degrades the electrical integrity of the flange to the ground connection.
5 feet deep is not in the ideal dirt composition for low impedance.
A cadweld connection, to a ground rod, is more positive.
Ronald: A typical 20 foot light pole, will have a 5 foot base. The flange, on the pole, will bolt to the base. The combination of rust, and metal oxidation, degrades the electrical integrity of the flange to the ground connection.
5 feet deep is not in the ideal dirt composition for low impedance.
A cadweld connection, to a ground rod, is more positive.
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