Does anybody ever oversize Grounding Electrode Conductors for long runs?

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marmathsen

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Seattle, Washington ...ish
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Electrical Contractor
I've got a residential project where the Ufer was installed where we originally thought the service equipment would go, but now the equipment is going about 125 wire feet away. That's a lot farther than I would normally run for the one and only Grounding Electrode on the property. Is it ridiculous to consider oversizing it because of the length?

It's a 320A service so I'm looking at running 2AWG Cu minimum.

Thanks in advance for your input.
 
The ufer GEC does not need to be larger than 4AWG copper.

I don't think there is any requirement to upsize the GEC for distance.
 
I agree with edward the NEC is silent on the length. IMO there is no real benifit from increasing the size over the #4 AWG minimum required by the NEC.
 
Are you required to use a ufer? If not could you abandon the ufer and install ground rods instead? I think the NEC doesn’t mention changing conductor size for length because it’s supposed to be by the service so it won’t be a long ways away.


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edward said:
The ufer GEC does not need to be larger than 4AWG copper.

I don't think there is any requirement to upsize the GEC for distance.
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Thank you for drawing my attention to the 250.66(C) allowance not to be larger than 4AWG. That would have been a pretty stupid mistake. Especially as expensive as wire is right now.

rainwater01 said:
Are you required to use a ufer? If not could you abandon the ufer and install ground rods instead? I think the NEC doesn’t mention changing conductor size for length because it’s supposed to be by the service so it won’t be a long ways away.


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Click to expand...

Yes I am required to have a Ufer electrode at this project.

Rob G
 
roger said:
So long lengths of conductor in contact with the earth is a problem when speaking of grounding electrodes?

Roger
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I think that he's referring to the length of the GEC. I'm curious to hear his thoughts on why long GEC's can be a problem. In 100+ years of system grounding I don't believe that the NEC ever addressed potential issues with GEC length.
 
Well there is a limit of 75' for bonding Csst piping. The only help the nec gives is this... I may have missed other info

(B) Effective Grounding Path. The connection of a grounding
electrode conductor or bonding jumper to a grounding
electrode shall be made in a manner that will ensure an effective
grounding path. Where necessary to ensure the grounding
path for a metal piping system used as a grounding electrode,
bonding shall be provided around insulated joints and around
any equipment likely to be disconnected for repairs or replacement.
Bonding jumpers shall be of sufficient length to permit
removal of such equipment while retaining the integrity of the
grounding path.
Click to expand...
 
infinity said:
I think that he's referring to the length of the GEC. I'm curious to hear his thoughts on why long GEC's can be a problem. In 100+ years of system grounding I don't believe that the NEC ever addressed potential issues with GEC length.
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Don't give them any ideas. Article 250 is already awash with stuff that serves no real purpose.
 
infinity said:
I think that he's referring to the length of the GEC.
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And that is my point, the conductor itself is a GE and the longer the better. If you simply ran a long piece of wire in the earth you don't need a rod, pipe, cee, etc...

Roger
 
infinity said:
I think that he's referring to the length of the GEC. I'm curious to hear his thoughts on why long GEC's can be a problem. In 100+ years of system grounding I don't believe that the NEC ever addressed potential issues with GEC length.
Click to expand...
Lightning and/or a primary event that manifests on the secondary are mitigated via mass and proximity.

Herbert Ufer's philosophy only took the nec 60 years to come to fruition , while denying 'earth' is a conductor, but insisting an R factor be present (25ohms<)

Lightning , or any heavy charge of caliber, also seeks straighter lines , farmers knew this before franklin :cool:

Is there a 780 guy in the house?

~RJ~
 
Greentagger said:
The issue is addressed at 250.4(A)(1) Informational Note No. 1.
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Informational Note No. 1: An important consideration for limit‐
ing the imposed voltage is the routing of bonding and ground‐
ing electrode conductors so that they are not any longer than
necessary to complete the connection without disturbing the
permanent parts of the installation and so that unnecessary
bends and loops are avoided.

basic theory , but no math.....
:rolleyes:
~RJ~
 
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