# Feeder equipment grounding conductor



## Rambler (Sep 29, 2013)

Other than, "You're not supposed to" or "it violates the NEC" I am trying to figure out the issues with running a fourth conductor (egc) from a main panel to a sub panel so that the N-G can be separated. 

It would be an insulated # 6 THHN ran by itself through the attic attached to the rafters. It may be tywrapped to the outside of the SE cable if possible.

I figure it has something to do with the inductive reactance of the conductor and since it's not routed with the other conductors there are no opposite magnetic fields to cancel it out in the event of a fault, thus increasing the impedance of the conductor and defeating the purpose of it.

Is this something to be worried about on a 70 amp feeder? I know, I know, I should rip it all out and re-install 4 wire feeder.....this is not a business deal, it's a friend of mine picking my brain.


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## HARRY304E (Sep 15, 2010)

Rambler said:


> Other than, "You're not supposed to" or "it violates the NEC" I am trying to figure out the issues with running a fourth conductor (egc) from a main panel to a sub panel so that the N-G can be separated.
> 
> It would be an insulated # 6 THHN ran by itself through the attic attached to the rafters. It may be tywrapped to the outside of the SE cable if possible.
> 
> ...



Is the EGC going to be run along with the feeder?


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## Dennis Alwon (May 9, 2009)

Iy you ran an equipment grounding conductor next to the seu you would then have a neutral that is uninsulated. Why not replace the cable if possible.


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## SparkyDino (Sep 23, 2013)

Dennis Alwon said:


> Iy you ran an equipment grounding conductor next to the seu you would then have a neutral that is uninsulated. Why not replace the cable if possible.


yeah with conduit :whistling2::thumbup:

:laughing::laughing::laughing:


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## Rambler (Sep 29, 2013)

Dennis Alwon said:


> Iy you ran an equipment grounding conductor next to the seu you would then have a neutral that is uninsulated. Why not replace the cable if possible.


It's ridiculous, I know. Part of the problem is the cable is not really accessible for the whole run, so he (we) would have to run a portion of it on the outside of the house. It's like the house was built around the cable, seriously.

I am really curious about the possible choke effect due to running a solo 
conductor. In the event of a ground fault would there be enough impedance to make it worthless.


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## wildleg (Apr 12, 2009)

300.3 b


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## don_resqcapt19 (Jul 18, 2010)

While that is a code violation, there will be no problems caused by installing the EGC in that manner. There would be a small increase in the inductive reactance, but not enough to make any real difference.

I think, as Dennis suggested, the bare grounded conductor is a bigger issue.


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## Rambler (Sep 29, 2013)

Yeah, I think replacing the cable is best and the right thing to do. 

Thanks.


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