Ground Rings

[zooby]

Trying to get a better understanding ---A ground ring is one of many ways to get a Grounding Electrode System per 250.50.......
A ground ring is a Grounding Electrode per 250.52 A (4)..... ( this can be both an electrode AND gec? )
A ground ring shall be buried not less than 30" per 253 F....

During construction with some new buildings added, I found that most areas of the ground ring were not close to depth -I tried bring attention to the issue. Of course signage is being added and the ring was hit. I know there had been several hits during construction since pics were taken when found. So....why a "ring" around the structure? And.. is the rings purpose defeated if there is a break that we do not know about?

My thoughts are that since the ring is one of "a few" grounding electrodes, the system is of course safe. I also feel that we paid to have a properly installed system and by code, we did not get that. As for any repair- the 2/0 that was hit pulled up and out a couple feet away. Anyhow, thanks for any insight on "The Ring" Doug

 

[infinity]

IMO a ground ring is a waste of money. First in needs to encircle the entire structure potentially making it hundreds of feet in length. Secondly it needs to be buried a minimum of 30". Given the cost of the material, trenching and installation I'm not seeing a great return on investment. A CEE would be a much better option and since it requires no supplementation connect to it and you're done.

Certainly if an existing ring is damaged it should be repaired.

 

[winnie]

To count as a grounding electrode, the ring must be of a particular depth.

But you can also have bare copper wire buried in soil simply acting as a jumper between grounding electrodes.

-Jonathan

 

[zooby]

To count as a grounding electrode, the ring must be of a particular depth.

But you can also have bare copper wire buried in soil simply acting as a jumper between grounding electrodes.

-Jonathan

thanks!

 

[zooby]

IMO a ground ring is a waste of money. First in needs to encircle the entire structure potentially making it hundreds of feet in length. Secondly it needs to be buried a minimum of 30". Given the cost of the material, trenching and installation I'm not seeing a great return on investment. A CEE would be a much better option and since it requires no supplementation connect to it and you're done.

Certainly if an existing ring is damaged it should be repaired.

Thanks for this and....CEE?

 

[infinity]

Thanks for this and....CEE?

Concrete Encased Electrode.

 

[tom baker]

A CEE, or ufer ground is the most cost effective grounding electrode available. With it, no ground rods are required.

 

[electrofelon]

IMO a ground ring is a waste of money. First in needs to encircle the entire structure potentially making it hundreds of feet in length. Secondly it needs to be buried a minimum of 30". Given the cost of the material, trenching and installation I'm not seeing a great return on investment. A CEE would be a much better option and since it requires no supplementation connect to it and you're done.

Certainly if an existing ring is damaged it should be repaired.

Yeah it's a strange option. Why does it have to "encircle the building"? Most other electrodes are 8-20 feet of material in contact with the dirt. Why not just allow 20 feet of wire and leave it at that?

 

[infinity]

Yeah it's a strange option. Why does it have to "encircle the building"? Most other electrodes are 8-20 feet of material in contact with the dirt. Why not just allow 20 feet of wire and leave it at that?

Good question. Makes it pretty undesirable as an electrode.

 

[winnie]

My _guess_ is that ground rings have some value in some other domain (radio work, equipotential bonding for lightning protection, static protection for the chemical industry, etc) and the NEC folk sort of shoe-horned it in.

-Jonathan

 

[tom baker]

My _guess_ is that ground rings have some value in some other domain (radio work, equipotential bonding for lightning protection, static protection for the chemical industry, etc) and the NEC folk sort of shoe-horned it in.

-Jonathan

Ground rings are often used for cell towers, ie as you pointed out for lightning protection.

 

[tom baker]

A CEE, or ufer ground is the most cost effective grounding electrode available. With it, no ground rods are required.

There is considerable literature available on line about advantages of CEE. If a qualifying CEE exists it must be used

 

[zooby]

My _guess_ is that ground rings have some value in some other domain (radio work, equipotential bonding for lightning protection, static protection for the chemical industry, etc) and the NEC folk sort of shoe-horned it in.

-Jonathan

I did leave out that there is a lightning "protection" system involved here but for my sake I was trying to keep it .....simple(?). I do know the LP guys are tied on to the ring in some areas. So I work at a zoo and these new structures do house or contain chimps....FWIW

 

[zooby]

Yeah it's a strange option. Why does it have to "encircle the building"? Most other electrodes are 8-20 feet of material in contact with the dirt. Why not just allow 20 feet of wire and leave it at that?

I admit that the "encircle" part made me ponder if there was some grounding magic by having that.

 

[winnie]

Another  guess: if the ground ring is for a lightning protection system, then perhaps the intent is to act like an equipotential system during a strike, so that the entire enclosed region floats at the same voltage.

The effect of the open center of the circle would depend on how much lightning dissipation to earth is 2D or 3D. Reducing step potential at a substation requires a grounding grid, but that is at 60 Hz. A lightning event is much higher frequency.

But again this is me guessing, I don't know the science of lightning protection systems

Jonathan

 

[zooby]

Another  guess: if the ground ring is for a lightning protection system, then perhaps the intent is to act like an equipotential system during a strike, so that the entire enclosed region floats at the same voltage.

The effect of the open center of the circle would depend on how much lightning dissipation to earth is 2D or 3D. Reducing step potential at a substation requires a grounding grid, but that is at 60 Hz. A lightning event is much higher frequency.

But again this is me guessing, I don't know the science of lightning protection systems

Jonathan

hmmm.... so I rabbit holed to NFPA 780 and while interesting I can only spend so much time looking into this. One thing I noticed was (to me) it read as if ..the ground ring for lightning protection did not have to be at the depth that the NEC states in 250. it's crystal clear Thanks for your input!

 

[electrofelon]

Here is what they should do: if you don't have an ufer, you need 20 feet of any combination of #6 CU or pipe/rod in contact with dirt . Done.