What is the difference between a ground grid vs ground ring?

[dbadger]

What is the difference between a ground grid vs ground ring? Per the NEC a ground ring has to be copper. Does a grounding grid have any material requirements?

 

[tom baker]

A ground ring is an article 250 grounding electrode with specific requirements.
I have heard of grounding grids in industrial plants, perhaps rebar, but other than that I don’t know

 

[ptonsparky]

My SEWAG.
A ring is a grounding electrode.
A grid is used to eliminate or reduce step potential.

 

[Dennis Alwon]

I believe the op means ground plate for the grid. A ground ring encircles the building with , I believe , a #2

Here it is

(4) Ground Ring.
A ground ring encircling the building or structure, in direct contact with the earth, consisting of at least 6.0 m (20 ft) of bare copper conductor not smaller than 2 AWG.

(7) Plate Electrodes.

Each plate electrode shall expose not less than 0.186 m2 (2 ft2) of surface to exterior soil. Electrodes of bare or electrically conductive coated iron or steel plates shall be at least 6.4 mm (1⁄4 in.) in thickness. Solid, uncoated electrodes of nonferrous metal shall be at least 1.5 mm (0.06 in.) in thickness.

 

[quantum]

What is the difference between a ground grid vs ground ring? Per the NEC a ground ring has to be copper. Does a grounding grid have any material requirements?

Grounding grids are standard at industrial job sites. A grounding ring is very specific (NEC 250.52(A)(4)) and must consist of at least 20ft of bare copper 2 AWG or larger in direct contact with the earth.

Grounding grids are normally thousands of feet long and are normally designed in a grid fashion (parallel and perpendicular crossings) and can consist of dozens or hundreds of ground rods. They are usually insulated conductors (THW/RHW/XHHW), sometimes bare copper, and many times type HMWPE.

Tap conductors normally extend from the grid and bond every piece of equipment or skid together on location. It normally wraps the fence perimeter as well and bonds fence posts and even up to the barb wire. Normally the cables are insulated, that alone disqualifies it from being a ground ring. Certainly when bare, it would qualify as a ground ring. When insulated, I personally consider ground grids to be a system of bonding jumpers interconnecting all of the grounding electrodes together, but that's just my opinion.

 

[Sea Nile]

Is this a swimming pool question?

Because the shell of a pool doesn't have to be copper.

 

[rc/retired]

Is this a swimming pool question?

No

 

[Sea Nile]

No

Was asking the OP. Not sure how you can definitively know for sure what he was asking. I only asked because 680.26 also talks about grids and rings so I was just asking the OP.

 

[rc/retired]

Was asking the OP. Not sure how you can definitively know for sure what he was asking. I only asked because 680.26 also talks about grids and rings so I was just asking the OP.

My apologies to you. However the OP hasn't responded since the original question. And there is absolutely no indication of this being related to a swimming pool whatsoever.
I just figured I'd answer your question so you don't have to spend the rest of your life wondering.

Ron

 

[Sea Nile]

Lol, let me know if I can answer any questions that have been plaguing you for years. JK. No need to apologize. Life's too short to worry about someone else's understanding of the code. Besides I post so often here that I forget about it when the thread goes cold.

 

[Isaiah]

What is the difference between a ground grid vs ground ring? Per the NEC a ground ring has to be copper. Does a grounding grid have any material requirements?

The ring is an electrode, just like several others that must be bonded to the service, - where it exists. This is a code requirement -250.50
The grid is an equipotential plane that keeps everything at the same potential - this is for step touch potential. This is not a code requirement but is a common practice for heavy industries.


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[tom baker]

Lol, let me know if I can answer any questions that have been plaguing you for years. JK. No need to apologize. Life's too short to worry about someone else's understanding of the code. Besides I post so often here that I forget about it when the thread goes cold.

We have many posts with an initial answer, a lot of replies, but never hear back from the OP.

 

[Speedskater]

off topic but there are several different grounding grids"

Grounding Systems

SRPP :: System Reference Potential Plane
STGP :: Signal Transport Ground Plane
ZSRG :: Zero Signal Reference Grid
ZSRG :: Zero Signal Reference Conductors
ZSRP :: Zero Signal Reference Potential
ZSRP :: Zero Signal Reference Plane
MESH-CBN :: Meshed Common Bonding Network
MESH-IBN :: Meshed Isolated Bonding Network
PEC :: Paralleled Earth Conductors
PBC :: Paralleled Bonding Conductors

Conductive Structure

 

[Isaiah]

off topic but there are several different grounding grids"

Grounding Systems

SRPP :: System Reference Potential Plane
STGP :: Signal Transport Ground Plane
ZSRG :: Zero Signal Reference Grid
ZSRG :: Zero Signal Reference Conductors
ZSRP :: Zero Signal Reference Potential
ZSRP :: Zero Signal Reference Plane
MESH-CBN :: Meshed Common Bonding Network
MESH-IBN :: Meshed Isolated Bonding Network
PEC :: Paralleled Earth Conductors
PBC :: Paralleled Bonding Conductors

Conductive Structure

Which one applies to IEEE-80?


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[Speedskater]

Isn't IEEE-80 about outdoor grounding of sub-stations.
These 'grounding systems' are more about inside buildings that are used as data centers and the like.

 

[shortcircuit2]

There is also the Motorola R56 grounding standard

 

[Isaiah]

Isn't IEEE-80 about outdoor grounding of sub-stations.
These 'grounding systems' are more about inside buildings that are used as data centers and the like.

Ok I was just asking - yes IEEE-80 is it a utility SS grid


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[ZaleHarris]

So if a ground ring with 4 ground rods and 4 0 connected by Cad-weld in parallel, what is the proper method of testing earth ground resistance?

 

[Sea Nile]

So if a ground ring with 4 ground rods and 4 0 connected by Cad-weld in parallel, what is the proper method of testing earth ground resistance?

I'm not aware of any need to test the earth ground resistance. But it seems like your scenario is overkill. There are ways of testing this, look for the free videos on the mike holt website. NEV or grounding would be the key words I would search for.

 

[ptonsparky]

So if a ground ring with 4 ground rods and 4 0 connected by Cad-weld in parallel, what is the proper method of testing earth ground resistance?

The engineer requesting this information would likely indicate which test method he would accept. I've only done a couple and don't really think anyone paid attention to the results. Mine used some reference rods and the Rod being tested. I've never used the Clamp style.