Ground size for Ground Rods

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jaykool

Member
Location
NE
I have always specified #4/0 bare copper ground between rod and other bonding surface (panel, steel, etc.).

Rods are either 5/8" or 3/4".

Is #4/0 overkill? This is for an industrial application.
 

hillbilly

Senior Member
If your GEC is running solely to a ground rod, pipe or plate electrode, #6cu is OK...250.66(A)
Anything else, you need to use Table 250.66

steve

Dang..Typed too slow again.
 

Buck Parrish

Senior Member
Location
NC & IN
Yes, but it is easier to carry one size on the truck. And #4 will get more use to grding. electrodes. And you will acummalate small pieces to go to the grd. rods.
If you are not doing services in mass, that is.
 

tom baker

First Chief Moderator
Staff member
I use 2 AWG BSC to my ground rods for radio antenna masts. The 2 is cadwelded to the mast and some of it is exposed. 6 AWG is small and could be easily damaged by a shovel. This applicaion is for public safety and is expected to have a long installed service life.
But otherwise I would use 6 AWG if protected, often will use 4 AWG if exposed.
 

infinity

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Location
New Jersey
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Journeyman Electrician
I have always specified #4/0 bare copper ground between rod and other bonding surface (panel, steel, etc.).

Rods are either 5/8" or 3/4".

Is #4/0 overkill? This is for an industrial application.

IMO yes. But hey it's not my money. :grin:
 

Dennis Alwon

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Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I have always specified #4/0 bare copper ground between rod and other bonding surface (panel, steel, etc.).

Rods are either 5/8" or 3/4".

Is #4/0 overkill? This is for an industrial application.
I think your question has been answer but I want to state if these jobs are new construction then you should be using a concrete encase electrode (in the footing) instead of ground rods.
 

srisser

Member
I think your question has been answer but I want to state if these jobs are new construction then you should be using a concrete encase electrode (in the footing) instead of ground rods.

The concrete encased electrodes would only be present if there is reinforcing steel present in the footings or foundation. Our jurisdiction has approved quite a few structures with un-reinforced footings, foundation walls, and wire mesh (<0.5 in dia.) in concrete floor slabs. FYI.
 

raider1

Senior Member
Staff member
Location
Logan, Utah
The concrete encased electrodes would only be present if there is reinforcing steel present in the footings or foundation. Our jurisdiction has approved quite a few structures with un-reinforced footings, foundation walls, and wire mesh (<0.5 in dia.) in concrete floor slabs. FYI.

You are correct. Not all locations require reinforcing of concrete for footings and foundations. In areas that are high seismic zones footing reinforcing is typically required.

Chris
 

iwire

Moderator
Staff member
Location
Massachusetts
When we build pads for power company transformers their rules require 4/0 bare cad welded to 3/4" x 10' rods. I think the this is as much for durability as any electrical issue.
 

Dennis Alwon

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Location
Chapel Hill, NC
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The concrete encased electrodes would only be present if there is reinforcing steel present in the footings or foundation. Our jurisdiction has approved quite a few structures with un-reinforced footings, foundation walls, and wire mesh (<0.5 in dia.) in concrete floor slabs. FYI.
Not quite true. You can also install 20 feet of #4 copper in the footing and it is still a CEE even without the rebar.
 

infinity

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Location
New Jersey
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Journeyman Electrician
Not quite true. You can also install 20 feet of #4 copper in the footing and it is still a CEE even without the rebar.


Dennis I think that he's trying to say that without the rebar the CEE is not considered present and therefore not required.
 

Dennis Alwon

Moderator
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Location
Chapel Hill, NC
Occupation
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Dennis I think that he's trying to say that without the rebar the CEE is not considered present and therefore not required.

That may be , I don't know but in either case my original point was not that it is required but that it would be better to use than the ground rods. ;)
 
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