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#84968 - 05/21/03 02:47 AM Re ground?  
ga.sparky56  Offline
Member
Joined: Nov 2002
Posts: 558
young harris georgia usa
Is it ever permissible to re ground a grounded conductor on the load side of the service disconnecting means? I'm talking drive a ground rod and reground.

I know it's permitted in 250.32(B) at out buildings,but outbuildings aside, is there a code art. that specifically adresses this?

To further clarify,I'm not saying bond to any enclosures or anything of the sort.Just drive a ground rod,and say for example take a piece of # 6 bare cu. from it to a subpanel and land it in the neutral bar (not bonded to the panel),or for that matter take a piece of #12 barecu. from said rod to a jbox,break the neutral(or grounded conductor) and reground it.

Code aside, what electrical problems would this create?

No I'm not legally insane,just want to settle an arguement. I think I know the answer but need clarification.

Russell


2017 / 2014 NEC & Related Books and Study Guides

#84969 - 05/21/03 06:44 AM Re: Re ground?  
Redsy  Offline
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
I know there is controversy surrounding the POCOs utilizing the earth as a conductor.
By doing what you describe, you would be creating an additional earth current. I think this would, to varying degrees, result in a voltage gradient that could cause "step voltage" hazards.

[This message has been edited by Redsy (edited 05-21-2003).]


#84970 - 05/21/03 07:09 AM Re: Re ground?  
George Corron  Offline
Member
Joined: May 2001
Posts: 717
Lorton, Va USA
Supplementary grounding is permitted per Article 250-54 (99 ref.). You can NOT use the earth as a return, but are allowed to supplement anywhere you feel necessary.

One example of this is parking lot lights. You must carry your equipment ground with you, but if you are in an area with thunderstorms and lightning, you are wise to add a ground rod at each pole base.

Remember the basic theory behind ground rods is equipotential plane, long runs or sensitive equipment your plane can get a bit stretched. Supplementals are not utilized enough, just make certain you are not replacing the equipment ground.


#84971 - 05/21/03 08:10 AM Re: Re ground?  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
See 250.24(A)(5). Rebonding the grounded conductor is rarely permitted. The second building example is one place where it is permited, but in general you can't connect the grounded conductor to earth after it leaves the service disconnect enclosure.
Don


Don(resqcapt19)

#84972 - 05/21/03 10:43 AM Re: Re ground?  
George Corron  Offline
Member
Joined: May 2001
Posts: 717
Lorton, Va USA
Don,
Thanks, I obviously read his post too quickly. You do NOT rebond the neutral, but can supplement the EGC, or GEC if you like, anywhere you believe necessary.


#84973 - 05/21/03 05:35 PM Re: Re ground?  
BGaquin  Offline
Junior Member
Joined: May 2003
Posts: 14
Sterling, VA
If I understand your question “is it ever permissible to reground a GROUNDED CONDUCTOR “The Neutral” in most systems. Other than the one item you mentioned the answer is no. The examples listed are for re-grounding a grounding conductor.

A Neutral/grounded conductor that is grounded downstream from the main disconnect, can cause current to flow on the ground system. The equipment grounding conductor will be in parallel with the neutral/grounded conductor. This will effect to operation of ground fault devices, can cause Power Quality issues and in some instances be a life safety issue


#84974 - 05/21/03 06:35 PM Re: Re ground?  
kale  Offline
Member
Joined: Nov 2002
Posts: 174
Once again, the --GEC, EGC, grounded conductor, grounding conductor-- terminology problem raises its ugly head. [Linked Image]


#84975 - 05/23/03 10:00 PM Re: Re ground?  
ga.sparky56  Offline
Member
Joined: Nov 2002
Posts: 558
young harris georgia usa
Thanks for the replies guys. [Linked Image]


#84976 - 05/24/03 07:36 AM Re: Re ground?  
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,303
The issue is conceptual.

One can have a number of SDS's 'reground' within a structure, or 250.32 a 3-wire feeder to an outbuilding close to the 'supply' building.

Either/Or ends up with gauss or stray voltage bettween the two methods

Then the PQ guys get the biz..... [Linked Image]

This is due to the NEC's stance that the earth is not a conductor, despite other international methods


#84977 - 05/24/03 08:16 AM Re: Re ground?  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
Quote
One can have a number of SDS's 'reground' within a structure,


Isn't this different then regrounding the grounded conductor downstream?

In the case of an SDS you have a new/created neutral that must be grounded.

In the opening post it was regrounding a conductor that was already grounded.


Bob Badger
Construction & Maintenance Electrician
Massachusetts

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