svaurez
Member
- Location
- California
I read on this forum that a ground ring electrode must encircle the ENTIRE building.Was this the NEC's intention or is the ground ring just 20' of #2 buried in the dirt.
Ground Ring
- Thread starter svaurez
- Start date
- Status
- Location
- Massachusetts
Re: Ground Ring
svaurez
Member
- Location
- California
Re: Ground Ring
I have trouble believing they want the entire building surrounded with #2.They allow 10' of copper water pipe,an 8' ground rod,and a 2 by 2 copper plate as electrodes.20' of #2 will outclass any of these.
[ January 04, 2004, 10:46 AM: Message edited by: svaurez ]
I have trouble believing they want the entire building surrounded with #2.They allow 10' of copper water pipe,an 8' ground rod,and a 2 by 2 copper plate as electrodes.20' of #2 will outclass any of these.
[ January 04, 2004, 10:46 AM: Message edited by: svaurez ]
- Location
- Illinois
- Occupation
- retired electrician
Re: Ground Ring
The code requires that the ground ring encircle the building or structure. I agree that 20' of copper in a ditch should perform as well as a 20' ground ring, but the code does not list 20' of copper in a ditch as a grounding electrode.
Don
The code requires that the ground ring encircle the building or structure. I agree that 20' of copper in a ditch should perform as well as a 20' ground ring, but the code does not list 20' of copper in a ditch as a grounding electrode.
Don
Re: Ground Ring
The only place I have seen ground rings installed is around transformer pads. As is noted here, they would be too expensive to choose for most buildings. Maybe somebody should test 20 feet of #2 in the dirt, 40 inches down and submit the results to NFPA for inclusion in the NEC. That's how Ufer did it.
Nah, nobody will do that, there is no money in it.
The only place I have seen ground rings installed is around transformer pads. As is noted here, they would be too expensive to choose for most buildings. Maybe somebody should test 20 feet of #2 in the dirt, 40 inches down and submit the results to NFPA for inclusion in the NEC. That's how Ufer did it.
Nah, nobody will do that, there is no money in it.
- Location
- Massachusetts
Re: Ground Ring
Earl many of the large buildings we do have ground rings specified on the plans
Typically 4/0 bare around the building with taps of 4/0 to 2 AWG into building columns and footing rebars.
Most of these will exceed 1000' feet in length, some have been much longer than that, the last one I worked on was getting near 2500' of 4/0 just to get around the building.
Earl many of the large buildings we do have ground rings specified on the plans
Typically 4/0 bare around the building with taps of 4/0 to 2 AWG into building columns and footing rebars.
Most of these will exceed 1000' feet in length, some have been much longer than that, the last one I worked on was getting near 2500' of 4/0 just to get around the building.
Re: Ground Ring
The purpose of the ground ring is to create a low impedance ground plane. The impedance to earth is secondary.
The building steel will be closer to the same voltage, to earth, at all locations when connected to a low impedance ground plane.
When the equipment is multi point grounded there will not be a high common mode voltage.
The purpose of the ground ring is to create a low impedance ground plane. The impedance to earth is secondary.
The building steel will be closer to the same voltage, to earth, at all locations when connected to a low impedance ground plane.
When the equipment is multi point grounded there will not be a high common mode voltage.
brian john
Senior Member
- Location
- Leesburg, VA
Re: Ground Ring
We see ground rings in our area fairly regularly, espically when the customer has lightning protection on the building.
We see ground rings in our area fairly regularly, espically when the customer has lightning protection on the building.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Ground Ring
Earlydean: the test by Ufer was with 4 AWG in concrete. I have a copy of his 1960 IEEE article. If he did a study with 2 AWG in dirt could you send me the article year and date, I will order it from the IEEE.
Earlydean: the test by Ufer was with 4 AWG in concrete. I have a copy of his 1960 IEEE article. If he did a study with 2 AWG in dirt could you send me the article year and date, I will order it from the IEEE.
brian john
Senior Member
- Location
- Leesburg, VA
Re: Ground Ring
Dean:
there are so many variables in installing and testing ground electrode that a large test would need to be completed to achieve and usable data, depths, locations, time of year, variable soil conditions, corrosion/detrition over time. A large ring can over come some of these variables and makes the installation of lightning protection easier, for the connection of down conductors.
Dean:
there are so many variables in installing and testing ground electrode that a large test would need to be completed to achieve and usable data, depths, locations, time of year, variable soil conditions, corrosion/detrition over time. A large ring can over come some of these variables and makes the installation of lightning protection easier, for the connection of down conductors.
svaurez
Member
- Location
- California
Re: Ground Ring
One more quick question.
Does the ground ring have to be spliced to form a complete circle with a cadweld,or can the two ends just lay in the trench overlapping each other?
One more quick question.
Does the ground ring have to be spliced to form a complete circle with a cadweld,or can the two ends just lay in the trench overlapping each other?
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Ground Ring
It would have to be electricaly continuous, IMO.
It would have to be electricaly continuous, IMO.
friebel
Senior Member
- Location
- Pennsville, N.J.
Re: Ground Ring
To: svaurez;don_resqcapt19;dereck;tom baker;
I have been reading with interest your comments about a grounding ring around a building.
I realize the NEC allows you to have a ground-ring around a building. This has been my experience in industry with a ground-ring, which I would like to see removed from the NEC, and for this reason.
Many times when an excavating crew comes in with their front-end loader to remove some soil, they inadvertenly will break the ground wire, which as you know can be a potentially serious problem. We have gone extensively with the Ufer grounding system, along with the Main water line, and a driven ground for our grounding for a building.
I hope that you may see the concerns that I have with a ground-ring around a building that is not protected, and can be very easily broken, when excavating.
To: svaurez;don_resqcapt19;dereck;tom baker;
I have been reading with interest your comments about a grounding ring around a building.
I realize the NEC allows you to have a ground-ring around a building. This has been my experience in industry with a ground-ring, which I would like to see removed from the NEC, and for this reason.
Many times when an excavating crew comes in with their front-end loader to remove some soil, they inadvertenly will break the ground wire, which as you know can be a potentially serious problem. We have gone extensively with the Ufer grounding system, along with the Main water line, and a driven ground for our grounding for a building.
I hope that you may see the concerns that I have with a ground-ring around a building that is not protected, and can be very easily broken, when excavating.
- Location
- Massachusetts
Re: Ground Ring
I do not think there is a chance that you will see ground rings go away.
I have seen the problem you speak of as I have been called into repair broken ground rings from excavators.
The jobs I have worked specify a marking ribbon above the ground ring but when an excavator comes in with a 4' x 5' x 6' bucket it all gets picked up in one scoop. :roll:
I do not think there is a chance that you will see ground rings go away.
I have seen the problem you speak of as I have been called into repair broken ground rings from excavators.
The jobs I have worked specify a marking ribbon above the ground ring but when an excavator comes in with a 4' x 5' x 6' bucket it all gets picked up in one scoop. :roll:
Re: Ground Ring
The ground ring should be a minimum of 30 inches below finished grade. Breaking the continuity of the ring may have some effect on the performance of sensitive equipment but the resistance of the earth connection should not be compromised.
The ground ring is likely not the only electrode in the system.
A ring establishes both a building ground and an equipment ground.
The ground ring should be a minimum of 30 inches below finished grade. Breaking the continuity of the ring may have some effect on the performance of sensitive equipment but the resistance of the earth connection should not be compromised.
The ground ring is likely not the only electrode in the system.
A ring establishes both a building ground and an equipment ground.
pierre
Senior Member
- Location
- Westchester County, New York
Re: Ground Ring
Bennie
Could you explain how it forms an equipment ground?
Thanks
Pierre
Bennie
Could you explain how it forms an equipment ground?
Thanks
Pierre
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