Area controversy around sizing of GEC for ground rod

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wbalsam1

wbalsam1

Senior Member
Location
Upper Jay, NY
Recently, an inspector in upstate New York state failed an inspection where the electrical contractor had installed a service of 600 amperes. It was just a pedestal service, no building, foundation or water main involved. Just a pair of ground rods 5/8" X 8'. The contractor installed #4 cu to the rods and when the inspector showed, he failed him and demanded that the contractor install something in the neighborhood of 1/0 cu to the rods.
What's up with this kind of thinking?
 
jumper

jumper

Senior Member
Location
3 Hr 2 Min from Winged Horses
Why 4#? Assuming CU. Sole connection, right?

250.66(A) Connections to Rod, Pipe, or Plate Electrodes.
Where the grounding electrode conductor is connected to
rod, pipe, or plate electrodes as permitted in 250.52(A)(5)
or (A)(7), that portion of the conductor that is the sole connection
to the grounding electrode shall not be required to be
larger than 6 AWG copper wire or 4 AWG aluminum wire.
 
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
It gets more confusing because many times engineers on commercial jobs req. 3/0 to the rods so if the inspector sees a lot of that he may think the rod GEC needs to be the same size as 250.66 calls out.
 
wbalsam1

wbalsam1

Senior Member
Location
Upper Jay, NY
All the power utility companies that I know of in New York State require a minimum size of #4 cu for the GEC for rods even though the NEC permits #6.
 
G

gndrod

Senior Member
Location
Ca and Wa
Code rule?

Code rule?

wbalsam1 said:
Recently, an inspector in upstate New York state failed an inspection where the electrical contractor had installed a service of 600 amperes. It was just a pedestal service, no building, foundation or water main involved. Just a pair of ground rods 5/8" X 8'. The contractor installed #4 cu to the rods and when the inspector showed, he failed him and demanded that the contractor install something in the neighborhood of 1/0 cu to the rods.
What's up with this kind of thinking?
Click to expand...

What was the inspector's code reference and or reasoning?
 
wbalsam1

wbalsam1

Senior Member
Location
Upper Jay, NY
Pathetic.

Pathetic.

gndrod said:
What was the inspector's code reference and or reasoning?
Click to expand...

Believe it or not, he actually worried that the # 4 would not be able to clear a fault. The contractor tried to explain to him that the grounded conductor would function to do that...but he insisted the grounding electrode conductor was too small for the size of the service.
The way the story was related to me....he would not believe any other inspector, either and created quite a stir until the NFPA got involved and resolved in the contractor's favor.

Pathetic, if you ask me.
 
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
This guys is not only uneducated, I can deal with that, but he is bull headed. I would love to hook up a 3/0 copper to a rod directly from a breaker and show him that it won't clear the fault-- at least in most soils.
 
O

OregonSE

Member
Location
Oregon
This topic has come up hear in Oregon with the installation of the GEC . Example 200 amp service; When installing the GEC, if looping through the acorn clamp on the first rod and then to the second,The GEC would need to be a # 4 cpr AWG. Considering the connection between the 2 ground rods to be a bond and would be sized per 250.122 Option 2, run 2 seperate # 6 AWG cpr from the MDP to the individual rods. Some inspectors are looking for this.

jumper said:
Why 4#? Assuming CU. Sole connection, right?

250.66(A) Connections to Rod, Pipe, or Plate Electrodes.
Where the grounding electrode conductor is connected to
rod, pipe, or plate electrodes as permitted in 250.52(A)(5)
or (A)(7), that portion of the conductor that is the sole connection
to the grounding electrode shall not be required to be
larger than 6 AWG copper wire or 4 AWG aluminum wire.
Click to expand...
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
OregonSE said:
This topic has come up hear in Oregon with the installation of the GEC . Example 200 amp service; When installing the GEC, if looping through the acorn clamp on the first rod and then to the second,The GEC would need to be a # 4 cpr AWG. Considering the connection between the 2 ground rods to be a bond and would be sized per 250.122 Option 2, run 2 seperate # 6 AWG cpr from the MDP to the individual rods. Some inspectors are looking for this.
Click to expand...

More inspectors that need some Continuing Education classes. Where do they find these guys?
 
jumper

jumper

Senior Member
Location
3 Hr 2 Min from Winged Horses
OregonSE said:
This topic has come up hear in Oregon with the installation of the GEC . Example 200 amp service; When installing the GEC, if looping through the acorn clamp on the first rod and then to the second,The GEC would need to be a # 4 cpr AWG. Considering the connection between the 2 ground rods to be a bond and would be sized per 250.122 Option 2, run 2 seperate # 6 AWG cpr from the MDP to the individual rods. Some inspectors are looking for this.
Click to expand...

I am not sure I understand this.

iwire said:
250.122 has nothing to do with a GEC.
Click to expand...

Maybe he meant 250.102. I dunno.
 
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