Random CEE question

[don_resqcapt19]

How's that? The only requirement in (2017) 250.65(F) for bonding jumpers is the reference to 250.53(C), which I already discussed compliance with.

Cheers, Wayne

It should have said 250.64(F), and I don't see it as complying with any of the 3 permissions there.
(1) permits the bonding jumper to be run to another grounding electrode....does not do that
(2) permits each grounding electrode to have its conductor run to the service equipment individually....does not do that
(3) permits multiple bonding jumpers from multiple grounding electrodes to be connected at a 1/4 x2" bus bar....does not do that

 

[wwhitney]

It should have said 250.64(F), and I don't see it as complying with any of the 3 permissions there.

Yes, thank you.

Short answer:

250.64(F)(1) reads "The grounding electrode conductor shall be permitted to be run to any convenient grounding electrode available in the grounding electrode system where the other electrode(s), if any, is connected by bonding jumpers that are installed in accordance with 250.53(C)." I don't see this as specifying where the other end of the bonding jumper connects to. It just requires that each grounding electrode be connected either to "the" GEC or to a bonding jumper.

Long answer to follow.

Cheers, Wayne

 

[wwhitney]

OK, I was motivated to step back and review Article 250 Part III. If we take it as granted that one end of a GE bonding jumper has to be at the GE, I don't find any general explicit direction as to where the other end of the GE bonding jumper may land, beyond the requirement that all the GEs end up bonded together.

250.50 opens with "All grounding electrodes . . . shall be bonded together to form the grounding electrode system." 250.53(C) refers to "the bonding jumper(s) used to connect the grounding electrodes together." And 250.64(F) starts off "Grounding electrode conductor(s) and bonding jumpers interconnecting grounding electrodes shall be installed in accordance with (1), (2), or (3)." The text of 250.64(F)(1) is in the previous post. Anything else that I missed?

250.53(A)(2) "Supplemental Electrode Required" does however give explicit direction on where the supplemental electrode may be connected. It reads "The supplemental electrode shall be permitted to be bonded to one of the following" and item (3) is "Grounded service-entrance conductor."

The scenario under discussion (which differs a little from the OP) is "ground rod - GEC - grounded service conductor in the meter base" along with " CEE - bonding jumper - subpanel feeder EGC - main bonding jumper - grounded service conductor in the separate service disconnect." If we deleted "subpanel feeder EGC" from the latter connection path, then it clearly complies with 250.53(A)(2)(3). And I think it would comply even if the electrode connected via the GEC to the meter base wasn't one of the types for which 250.53(A) requires a supplemental electrode.

So we are just left with the original question I raised, whether there is a prohibition on an EGC serving a dual role as a GE bonding jumper. So far the answer seems to be no.

Cheers, Wayne

 

[wwhitney]

Looking back at the picture in post #13, the situation is not clear to me. The picture of the interior panel shows the CEE landed on a terminal to the grounded supply conductor. And while the supply is carried by SER cable, the bare conductor of the cable is not connected. I'm not familiar enough with the panel to tell if there's a screw-type main bonding jumper installed. Seems like a couple possibilities:

- The supply is a feeder, so any bonding screw will be removed and the SER bare conductor will be landed on a grounding bar. Then the CEE should land on that grounding bar instead of the grounded supply conductor, and the earlier discussion of "feeder EGC as bonding jumper" applies.

- The supply is intended to be a service. Which would work under the 2020 NEC if the outside disconnect is an "Emergency Disconnect - Not Service Equipment," and the panel is nearest the point of entry (which seems unlikely, as it is in an interior wall, but that gets interpreted different ways in different places). Then the bare SER conductor goes unused, the CEE is properly connected to the grounded service conductor, and there is or will be a main bonding jumper. No problems.

Cheers, Wayne

 

[Tulsa Electrician]

Jackflash, my take on it based on your year of code.
I would start with either bond the nipple between the meter and the service disconnect or replace it with a PVC offset nipple. I would prefer PVC that's just me others would prefer the use of a grounding lock nut and or bushing.

Next since the service disconnect is next to the meter out side. That is you MBJ location. This means reroute you #4 per NEC to this location. Forget any thing else.
Then treat the wire going to the basement as a feeder and wire as such. Then the panel in basement is a sub panel. Separate you grounded ( neutrals) and EGC. That type of install is very common and consistent.

The biggest issue I see is with the service disconnect. There is no lug for your EGC. You will need an EGC add a lug or a ground bar that will accept the wire size of the feeder cable. After you install your 2- MBJ supplied by the factory. You will enough lug space for this add a lug or addition wires for the bonding bridge etc.
I would go with a ground bar and lug for the EGC on feeder. There is a place in the disconnect ready from the factory to the left side.

As far as one rod for meter. That may be the minium utility requirement. Once you CEE is at your MBJ location no additional is required. Unless mandated by AHJ. I have worked in some areas area that require at least two GECs tied toghter as one. So we had to drive two rods in addition or use one of the other listed.
Since you have on rod the second can be added. Just wire accordingly.
Have fun and keep it simple.

 

[don_resqcapt19]

Yes, thank you.

Short answer:

250.64(F)(1) reads "The grounding electrode conductor shall be permitted to be run to any convenient grounding electrode available in the grounding electrode system where the other electrode(s), if any, is connected by bonding jumpers that are installed in accordance with 250.53(C)." I don't see this as specifying where the other end of the bonding jumper connects to. It just requires that each grounding electrode be connected either to "the" GEC or to a bonding jumper.

Long answer to follow.

Cheers, Wayne

That section is for where the GEC or bonding jumper originates at one electrode and terminates at a second electrode. I don't see that or any of the other list items in that section applying.

 

[wwhitney]

That section is for where the GEC or bonding jumper originates at one electrode and terminates at a second electrode.

I don't see how you read that text to say that the bonding jumper must terminate at a second electrode. Can you spell that out for me?

Thanks,
Wayne

 

[don_resqcapt19]

I don't see how you read that text to say that the bonding jumper must terminate at a second electrode. Can you spell that out for me?

Thanks,
Wayne

That is the only purpose for the section. The GEC is run to one electrode, and the bonding jumper(s) are run from the additional electrode(s) to the electrode that has the GEC connected to it.

The grounding electrode conductor shall be permitted to be run to any convenient grounding electrode available in the grounding electrode system where the other electrode(s), if any, is connected by bonding jumpers that are installed in accordance with 250.53(C).

 

[wwhitney]

I think it comes down to whether the word "where" in that text is denoting location, i.e. could be replaced by "to which." Versus "where" meaning "in the situation that," in which case the termination point of the bonding jumpers is unspecified. I have certainly been reading "where" in the latter sense, it sounds like you see it in the former sense.

Take the simple case of 2 ground rods as the entire GES. There must be an unspliced GEC connecting one ground rod to the grounded service conductor. And if the second ground rod is not connected via a GEC (either an extension of the first GEC, or a second GEC per 250.64(F)(2)), it must be connected via a bonding jumper.

So where can that bonding jumper land? 250.53(A)(2) provides a list of places. Are you saying that 250.64(F)(1) eliminates some of those as options?

Cheers, Wayne

 

[jaggedben]

Yes, I take that as a given.


Not sure of the point of the rule, but it provides relief from "250.50 or 250.53(C)" and so, for example, you could still do that without checking that the EGC size is sufficient, or if the EGC is not of the wire type. So the idea of EGC as bonding jumper doesn't render that section superfluous.


Given that 250.121 explicitly allows an EGC to function as a GEC within the specified limits, the above concerns are not unique to EGC as bonding jumper. Certainly "EGC as bonding jumper if it meets all the requirements for both" seems a natural corollary to 250.121, if not an explicit one.

Cheers, Wayne

As I said before, having the CEE at the sub is not so much a clear code violation per se as just a bad practice.