Neutrals and ground on the wrong bus.

[wwhitney]

Here's part of the problem. There is no EGC which exists entirely within the service disconnecting means enclosure.

A jumper from the grounded service conductor to the service disconnecting means enclosure meets the Article 100 definition of "Grounding Conductor, Equipment". So I disagree.

Cheers, Wayne

 

[Smart $]

A jumper from the grounded service conductor to the service disconnecting means enclosure meets the Article 100 definition of "Grounding Conductor, Equipment". So I disagree.

Cheers, Wayne

Also meets the definition of...

Bonding Conductor or Jumper. A reliable conductor to
ensure the required electrical conductivity between metal
parts required to be electrically connected.

It is generally understood that EGC's are conductor's from one equipment unit to another. Jumpers are used within, or as a redundant grounding means exterior to equipment units. Here's another case of interpretation blindness, perhaps even ignorance in this case.

 

[iwire]

Wayne what do you think the NFPA means by this?

90.1 Purpose.

(C) Intention. This Code is not intended as a design specification
or an instruction manual for untrained persons.

Here is my take, you love logic, you see beauty in it. But trying to find it in the NEC is going to be frustrating.

The NEC was not written by one person, or even one group or at the same point in time

I strongly doubt the CMP members are linguists, or examine things in the minute detail as you do. Perhaps they should but I get the impression things a little bit lax in that. This is shown when time and again any change made this cycle has to be readdressed the next cycle because they missed a detail

That being the case those of us who install and take inspections under the NEC learn what the common interpretations are.

When you take a stand the 'X is allowed' based only on your personal logic when those of us in the trade know it is not allowed by inspectors it seems a bit odd.

Just my thoughts, I am sure you guys will continue unresolved.

 

[wwhitney]

Here is my take, you love logic, you see beauty in it.

Indeed.

But trying to find it in the NEC is going to be frustrating.

You're telling me!

When you take a stand the 'X is allowed' based only on your personal logic when those of us in the trade know it is not allowed by inspectors it seems a bit odd.

Yes, I get that. I should say something like 'a strict logical reading of the NEC allows X' with the understanding that the NEC is a document with many users, and those users may share a common understanding of its meaning that differs from X.

But for this thread, I believe the common understanding is that within the enclosure of the service disconnecting means, EGCs may be landed on a common terminal bar with the grounded conductors. Is that correct? If so, in this case I am defending the common understanding, and Smart$ is proposing that the common understanding is wrong.

Cheers, Wayne

 

[wwhitney]

Also meets the definition of...

Bonding Conductor or Jumper. A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected.

Indeed it does. So it is both an EGC and a Bonding Jumper.

BTW that definition is rather odd. It is missing the verbiage about "normally non-current carrying" that is used in other locations, e.g. Article 250 Part V.

It is generally understood that EGC's are conductor's from one equipment unit to another. Jumpers are used within, or as a redundant grounding means exterior to equipment units.

That distinction is not present in anything you've quoted from the NEC. If we are going to rely on general understanding, then it is also generally understood that in the main service panel, EGCs and grounded conductors need not be separated.

If you are going to make an argument that a strict reading of the NEC yields a result different from general understanding, let's stick with the NEC as written. You can't have it both ways.

Here's another case of interpretation blindness, perhaps even ignorance in this case.

I believe I've made it clear that comments like this are offensive and don't advance the discussion. They are a sign of the weakness of your logical argument.

Cheers, Wayne

 

[Smart $]

Indeed it does. So it is both an EGC and a Bonding Jumper.

BTW that definition is rather odd. It is missing the verbiage about "normally non-current carrying" that is used in other locations, e.g. Article 250 Part V.

The terms are used exclusively. An Equipment Grounding Conductor is run with circuit conductors (and unless your circuit never leaves the service disconnecting means enclosure, you do not have an EGC). Bonding Conductors or Jumpers are not tied to circuit conductors. I'd actually prefer to use the term Equipment Bonding Conductor or Jumper, but that term is already taken and has a different meaning. The point in using that term is the "required" term, thus...

Bonding Jumper, Main. The connection between the
grounded circuit conductor and the equipment grounding
conductor at the service.

 

[Smart $]

...I believe I've made it clear that comments like this are offensive and don't advance the discussion. They are a sign of the weakness of your logical argument.

Sorry if you take offense from that comment. Unfortunately being blunt and truthful is sometimes offensive, though it may well be in the offended's best interest.

 

[wwhitney]

The terms are used exclusively.

I understand how the terms are commonly used, and I'm pointing out that the text of the NEC does not support that distinction.

I think an example would be helpful here, as I don't see that there's anything left to your argument. Consider a residential service panel consisting of one breaker in a metallic enclosure, so it provides both the service disconnecting means and OCPD. Suppose it has a single terminal bar on which are landed the service grounded conductor, the outgoing feeder grounded conductor, the outgoing feeder EGC, and the GEC. The installing electrician says that the terminal bar is the Main Bonding Jumper.

The service panel enclosure needs to be bonded, so there's two possibilities:

(A) the terminal bar is mounted to the enclosure, i.e. bonded by a screw or two.
(B) the terminal bar is isolated from the enclosure, so a bare copper wire is run to a lug on the enclosure.

Is either one of these a violation, and if so, of what section? If only one is a violation, how does that section distinguish between (A) and (B)?

Thanks, Wayne

 

[Smart $]

I understand how the terms are commonly used, and I'm pointing out that the text of the NEC does not support that distinction.

I think an example would be helpful here, as I don't see that there's anything left to your argument. Consider a residential service panel consisting of one breaker in a metallic enclosure, so it provides both the service disconnecting means and OCPD. Suppose it has a single terminal bar on which are landed the service grounded conductor, the outgoing feeder grounded conductor, the outgoing feeder EGC, and the GEC. The installing electrician says that the terminal bar is the Main Bonding Jumper.

The service panel enclosure needs to be bonded, so there's two possibilities:

(A) the terminal bar is mounted to the enclosure, i.e. bonded by a screw or two.
(B) the terminal bar is isolated from the enclosure, so a bare copper wire is run to a lug on the enclosure.

Is either one of these a violation, and if so, of what section? If only one is a violation, how does that section distinguish between (A) and (B)?

Thanks, Wayne

It appears you do not and will not see it, but I'll point out once again your consistent interpretation blindness.

Bonding Jumper, Main. The connection between the
grounded circuit conductor and the equipment grounding
conductor at the service.

It really is this simple and thus rest my argument.

 

[wwhitney]

I'll point out once again . . .

Bonding Jumper, Main. The connection between the grounded circuit conductor and the equipment grounding conductor at the service.

I don't think a definition is a violation.

What is the point of your emphasis on the word "between"? I read it as a synonym for "among." The following rewording is equivalent to the current definition, in my reading. "Bonding Jumper, Main. That which connects the grounded circuit conductor and the equipment grounding conductor at the service."

Where a grounded conductor terminal bus is fastened directly to the [metal] enclosure, the entire bus serves as the main bonding jumper.

In the above quote you indicated that a terminal bus can be the main bonding jumper, and from the context I believe you indicated that my scenario (A) is NEC compliant.

The definition you point out again certainly doesn't distinguish between scenarios (A) and (B), so if that is your only objection, then (A) being compliant means (B) is compliant.

Cheers, Wayne

 

[Smart $]

...
What is the point of your emphasis on the word "between"? I read it as a synonym for "among." ...

Grounded conductor <--> main bonding jumper <--> equipment grounding conductor.

BETWEEN

 

[wwhitney]

Grounded conductor <--> main bonding jumper <--> equipment grounding conductor.

BETWEEN

Say that's correct . . . how is a terminal bar at the service, on which the grounded service conductor and the EGCs are both landed, not "between the grounded circuit conductor and the equipment grounding conductor"?

Cheers, Wayne

P.S. If this is the crux of our disagreement, the meaning of "connection between", we could have gotten here quicker if there had been less condescension.

 

[electrofelon]

Say that's correct . . . how is a terminal bar at the service, on which the grounded service conductor and the EGCs are both landed, not "between the grounded circuit conductor and the equipment grounding conductor"?

Cheers, Wayne

P.S. If this is the crux of our disagreement, the meaning of "connection between", we could have gotten here quicker if there had been less condescension.

I pretty much agree with smart that either:
1) the code is very outdated on its terminology of the grounded bus/EGC bus/ MBJ arrangement or
2) 93% of service panelboards are in violation.

(I would tend to go with #1)

But Wayne brings up a point that I was also thinking as I was reading through and I would also like your thoughts on. Is there anything that says we can not have many MBJ's? Couldnt any/many sections of a "combo neutral/ground bar" be a MBJ?

 

[Smart $]

Say that's correct . . . how is a terminal bar at the service, on which the grounded service conductor and the EGCs are both landed, not "between the grounded circuit conductor and the equipment grounding conductor"?
...

...
But Wayne brings up a point that I was also thinking as I was reading through and I would also like your thoughts on. Is there anything that says we can not have many MBJ's? Couldnt any/many sections of a "combo neutral/ground bar" be a MBJ?

It all centers on the concept of single-point system grounding. I fail to see what about the requirements is so hard to understand and carry out. I think proponents subliminally attempt to create confusion and/or doubt to circumvent the requirements.

 

[Smart $]

...
P.S. If this is the crux of our disagreement, the meaning of "connection between", we could have gotten here quicker if there had been less condescension.

I often serve as a reflection.

 

[iwire]

Indeed.

I hope you know I was not disparaging you for that.

You're telling me!

Now for the part that is painful for me.

But for this thread, I believe the common understanding is that within the enclosure of the service disconnecting means, EGCs may be landed on a common terminal bar with the grounded conductors. Is that correct? If so, in this case I am defending the common understanding, and Smart$ is proposing that the common understanding is wrong.

I screwed up, with this much time in the forums I should know not to jump in without a full reading of all posts.

I do agree with you and my post that I thought was well thought out should have been aimed at smart $.

I will limp away now to lick my wounds. :ashamed1:

 

[kwired]

I pretty much agree with smart that either:
1) the code is very outdated on its terminology of the grounded bus/EGC bus/ MBJ arrangement or
2) 93% of service panelboards are in violation.

(I would tend to go with #1)

But Wayne brings up a point that I was also thinking as I was reading through and I would also like your thoughts on. Is there anything that says we can not have many MBJ's? Couldnt any/many sections of a "combo neutral/ground bar" be a MBJ?

Equipment marked suitable only for use as service equipment has a grounded conductor terminal bar bolted directly to enclosure with two bolts - which one is the MBJ? Are they both the MBJ? Or is there two MBJ's?

 

[K8MHZ]

Equipment marked suitable only for use as service equipment has a grounded conductor terminal bar bolted directly to enclosure with two bolts - which one is the MBJ?

The green one.

 

[Smart $]

Equipment marked suitable only for use as service equipment has a grounded conductor terminal bar bolted directly to enclosure with two bolts - which one is the MBJ? Are they both the MBJ? Or is there two MBJ's?

The green one.

Add to that, the one "between the grounded circuit conductor and the equipment grounding conductor".

:happyyes:

 

[jaggedben]

Add to that, the one "between the grounded circuit conductor and the equipment grounding conductor".

:happyyes:

That sounds to me like the neutral terminal bar in many service panels.