GEC run within a feeder conduit?

[marmathsen]

Can a grounding electrode conductor be run within the same conduit as a feeder? Not a separate building

If so then you would also still need an equipment grounding conductor as well within the same conduit?

And at the sub panel side would the GEC need to be kept separate from other EGCs, or could it be spliced to extend it to the electrode using the ground bar within the sub panel?

I have a couple projects that have very limited access from the service to the grounding electrode but being able to use the feeder conduit would make a world of difference.

Rob G
Seattle

 

[infinity]

If they're in the same building why would you need to run a GEC to a sub-panel?

 

[augie47]

Likewise I wonder why, but in answer to your question I see nothing prohibiting it but 250.64E might pose problems. You might look at 250.121 (17nec)

 

[LarryFine]

Apparently, if I read the OP correctly, the sub-panel has better new-GEC access than the main/service panel.

My understanding is that a single conductor may act as both as long as it meets the requirements of each.

I am not sure that using the sub-panel's EGC bus as a splice in a GEC is permissible, however.

 

[electrofelon]

If you are going to do this, I dont see any reason to run both a GEC AND a EGC, just use the same conductor to serve both purposes.

 

[marmathsen]

If they're in the same building why would you need to run a GEC to a sub-panel?

Likewise I wonder why, but in answer to your question I see nothing prohibiting it but 250.64E might pose problems. You might look at 250.121 (17nec)

Yes sorry I should have been more clear, I'm not looking to run the GEC to the sub panel but rather use the feeder conduit at a means to get my GEC closer to where the electrode is. So the wire would run from the service, through the conduit, then need to continue on to connect to the electrode (water line).

Apparently, if I read the OP correctly, the sub-panel has better new-GEC access than the main/service panel.

Correct

My understanding is that a single conductor may act as both as long as it meets the requirements of each.

I am not sure that using the sub-panel's EGC bus as a splice in a GEC is permissible, however.

If you are going to do this, I dont see any reason to run both a GEC AND a EGC, just use the same conductor to serve both purposes.

What if I used an irreversible crimp (or a couple) in the sub panel to essentially create a 3-way connection with 1 conductor from the service, 1 conductor heading off to the electrode, and 1 conductor feeding into the ground bar of the sub panel? That way I wouldn't be using the ground bar as a means to extend the GEC and I think would fulfill the requirements of 250.64(C)

 

[jaggedben]

I once had an inspector argue that doing this in a metal conduit creates objectionable current. The GEC is expected to carry current, or at least not expected to not carry current. (This was in San Francisco where the water network is still almost all metal underground so GECs do usually carry a bit of current.) 256.64(E) requires ferrous conduits and enclosures with a GEC to be bonded to the GEC at both ends, which will make the conduit a parallel path for any current on the GEC. It's a bit hard to argue with this inspector's interpretation because, absent an explicit permission to do what you want here (which I'm unaware of) objectionable current is undefined and therefore whatever the inspector wants to say it is.

Also I think it was in the 2014 NEC where this was outlawed but then in the next cycle they put in an exception that basically says you can use one conductor if it meets the requirements for both an EGC and GEC. See 250.121.