ECN Forum Forums Code Related Discussion NEC & other Code issues Grounding Electrode Conductor

gfretwell wrote: I am still not sure why he couldn't ground the service in one of the disconnects with a #2 and be done with it.

That's exactly what he should do. As long as the neutral is sized equal to or above the 250.66 size, it can ground either or both panels. Just because you are permitted to run GEC taps doesn't mean you have to.

Also, what size service entrance conductors were run on the line side of the meter? Need to make sure that a #2 is large enough by examining all of the SE conductors.

Here is a quote from Soares based on your described installation...

"If the installer chooses to, an individual grounding electrode conductor may be installed from each service disconnecting means enclosure to the grounding electrode.

In this case the GEC is sized for the service-entrance conductor serving that enclosure.

The code does not specifically address or prohibit this concept but it is similar to connecting taps to a common grounding electrode conductor. In this case the taps are connected directly to the electrode."

shortcircuit

Mark- There are no Service Entrance conductors on the line side of the meter. There is an underground lateral coming from the utility company to the meter and the utility company will not permit the GEC to orginate in their meter. I appreciate the reference to Soares and I guess since we have two service panels we are dealing with coming out of each panel with a properly sized GEC to the electrode system. As Greg indicated a person could use Note #1 of T. 250.66 and then based on the "Tap" rules come out of the other panel with a properly sized tap conductor and save the cost of installing two conductors all the way to the electrode.

"no Service Entrance conductors on the line side of the meter. There is an underground lateral coming from the utility company"

"underground lateral from the utility company" = "Service Entrance conductors"

And the GEC needs to be sized for them...

Anyway... I think its clear the code wants one GEC per lateral. Although Soares opinion might differ.... (What if one service is removed, and you have a just a #6 covering the grounding for 350MCM SE conductors?)

Commentary from 230.40 exception 2... "Note that in such cases the lateral conductors are considered [i]one service lateral."

Also, how can anyone do a complete job without knowing what the meter is fed with, (Not opening the meter) otherwise you would never know what size the GEC should be.

IMO the GEC crimps or welds should be right below the equipment. Or run a single conductor in and out of both panels. The allowing of taps seems to be making it easier for you... "the tap method eliminates the difficulties found in looping grounding electrode conductors from one enclosure to another." (From the commentary following 250.64(D) )

I think someone should read in Article 100 about the definition of "Service Entrance Conductors" - They are Not the lateral. And if your going to copy and paste from the NEC you might want to check the copyright permissions.

George:

Please look at this:
https://www.electrical-contractor.net/ubb/Forum1/HTML/006592.html

That should ally your concerns over quoting Code in the forums.

Thanks for the link and information on copy and paste. I was and still am not real comfortable with copying and pasteing but I feel better now and that's what this forum is all about. That said, I found some very enlightening information in Soares Grounding that covers the subject of this thread. Check out p.118 of Soares Grounding 8th edition. It appears that coming out of muliple Service panel and running to the Grounding Electrode with a GEC is one of many ways of complying with the NEC.

What I am curious about is whether the lugs in the meter enclosure are UL listed for more than one conductor???

George, "Service Entrance Conductors" can be pretty broad. (Depending on where you are...) Here, where I am, it is entrance to, or attachment to the building. Most service equipment and metering (customer owned) are inside... In terms of the definitions from the NEC, take a look at "Service Lateral", and "Service Point", both help determine where "Service Entrance Conductors" begin.

Anyway, my point was that what you have is two GEC's, and two connections to the water are a splice in what is supposed to be one conductor. (If you are inspecting to the NEC, not Soares...)

The code specifically permits the GEC to run from one electrode to another.
I cannot see how two GECs that are terminated on the same electrode would be a spliced GEC violation just because they both originated in the same vicinity. By that logic the separate service permitted for fire pumps could not be grounded to the electrodes that are used for the main service. In fact any failure to use the same electrodes for a separate service would be a violation of
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous for general use." Thomas Alva Edison