Neutrals and ground on the wrong bus.

[wwhitney]

Incorrect.

Incorrect back at you.

250.130(A) specifically states "The connection shall be made by bonding the equipment grounding conductor to the grounded service conductor and the grounding electrode conductor." The grounded service conductor ends at its termination to the grounded conductor terminal bus. The bus does not extend the service conductor.

OK, I agree with all of the above, but it has no direct bearing on the issue. Using the grounded conductor terminal bar is one way to connect the EGC to the grounded service conductor and complies with the above language.

Show me something in Article 250 that says that the 250.130(A) EGC to grounded service conductor connection can't be made that way. Or that removal of the Main Bonding Jumper has to sever all connections of the EGCs to the grounded service conductor.

I don't believe there is any such language, so the practice is permitted.

Cheers, Wayne

 

[Smart $]

Incorrect back at you.


OK, I agree with all of the above, but it has no direct bearing on the issue. Using the grounded conductor terminal bar is one way to connect the EGC to the grounded service conductor and complies with the above language.

Show me something in Article 250 that says that the 250.130(A) EGC to grounded service conductor connection can't be made that way. Or that removal of the Main Bonding Jumper has to sever all connections of the EGCs to the grounded service conductor.

I don't believe there is any such language, so the practice is permitted.

By your rationale, the neutral to ground connection in the following photo is compliant?

 

[Smart $]

...
Show me something in Article 250 that says that the 250.130(A) EGC to grounded service conductor connection can't be made that way. Or that removal of the Main Bonding Jumper has to sever all connections of the EGCs to the grounded service conductor.
...

Not explicit but 250.24(A)(1) states:

(1) General. The grounding electrode conductor connection
shall be made at any accessible point from the load end
of the overhead service conductors, service drop, underground
service conductors, or service lateral to, including
the terminal or bus to which the grounded service conductor
is connected at the service disconnecting means.

Why does Code specifically permit connection to the bus for a GEC and not specifically state similar for an EGC?

 

[wwhitney]

By your rationale, the neutral to ground connection in the following photo is compliant?

Of course not, 250.130 makes it clear that that 250.130(A) only applies to "equipment grounding conductor connections at service equipment."

Cheers, Wayne

 

[wwhitney]

Why does Code specifically permit connection to the bus for a GEC and not specifically state similar for an EGC?

Good question. My thought is that since the GEC is required to be unspliced, it is necessary to specify where it originates with greater precision.

Cheers, Wayne

 

[Smart $]

Of course not, 250.130 makes it clear that that 250.130(A) only applies to "equipment grounding conductor connections at service equipment."

So, if that receptacle was installed in the side of the service panel in question, in an insulating plastic plate attachment si it was not grounded through the strap, you'd be okay with that?

 

[Smart $]

Good question. My thought is that since the GEC is required to be unspliced, it is necessary to specify where it originates with greater precision.

Hmmm.

It's utterly amazing how your mind works. :blink:

 

[wwhitney]

It's utterly amazing how your mind works.

Thanks!

Cheers, Wayne

 

[wwhitney]

So, if that receptacle was installed in the side of the service panel in question, in an insulating plastic plate attachment si it was not grounded through the strap, you'd be okay with that?

The receptacle still wouldn't be service equipment, see the article 100 definition. So it still wouldn't fall under 250.130.

Cheers, Wayne

 

[Smart $]

The receptacle still wouldn't be service equipment, see the article 100 definition. So it still wouldn't fall under 250.130.

Cheers, Wayne

The receptacle would be in the same enclosure as the service disconnecting means, which means it is a connection at service equipment, does it not? Isn't that a part of the premise of your argument that the grounded conductor terminal bus is within the service equipment enclosure?

VII. Methods of Equipment Grounding

250.130 Equipment Grounding Conductor Connections.
... Equipment grounding conductor
connections at service equipment shall be made as indicated
in 250.130(A) or (B). ...

(A) For Grounded Systems. The connection shall be made
by bonding the equipment grounding conductor to the
grounded service conductor and the grounding electrode
conductor.

...

 

[wwhitney]

The receptacle would be in the same enclosure as the service disconnecting means, which means it is a connection at service equipment, does it not?

No.

The definition of service equipment starts off "The necessary equipment . . ." That receptacle isn't necessary, so it isn't service equipment. On the other hand, the grounded conductor terminal bar is the necessary disconnecting means for the grounded conductor, per 230.75.

Cheers, Wayne

 

[Smart $]

No.

The definition of service equipment starts off "The necessary equipment . . ." That receptacle isn't necessary, so it isn't service equipment. On the other hand, the grounded conductor terminal bar is the necessary disconnecting means for the grounded conductor, per 230.75.

All the terminals of the grounded conductor terminal bus are not necessary either, that is, for the service disconnecting means. What if the service disconnecting means were located prior to the panel and this panel was MLO. Would there be an identical grounded conductor terminal bus in that disconnecting means, and what would you use it for?

I fail to see the logic in your arguments. :huh:

 

[kwired]

What about equipment that is suitable only for use as service equipment?

Pump panels comes to mind - grounded conductor bus is not insulated it is mounted directly to the enclosure. In those applications I can't recall ever having a load on the grounded conductor (no 277 volt loads), If we can not land EGC's on the GC bus then we should have to install an additional EGC bus. I can possibly see that in wording of NEC - but still think it is totally pointless especially in that application.

 

[wwhitney]

What if the service disconnecting means were located prior to the panel and this panel was MLO. Would there be an identical grounded conductor terminal bus in that disconnecting means, and what would you use it for?

That depends, does the service disconnecting means have OCPD in it? I'll assume not, as otherwise the MLO panel is not service equipment, so there's nothing to discuss. So we need to check Article 250 carefully to see which items must be connected in the service disconnecting means, which items must be connected in the MLO panel, and which items can be connected in either.

For example, 250.24(A)(1) says the the grounding electrode conductor can't be landed in the MLO panel, it needs to be landed in the service disconnecting means or further upstream of it. Which is a little surprising to me.

I fail to see the logic in your arguments. :huh:

Article 250 is rather convoluted, so I'm just trying to follow what's written. You still haven't posted anything supporting the idea that removing the main bonding jumper needs to leave the EGCs disconnected from the grounded conductor.

Cheers, Wayne

 

[Smart $]

What about equipment that is suitable only for use as service equipment?

Pump panels comes to mind - grounded conductor bus is not insulated it is mounted directly to the enclosure. In those applications I can't recall ever having a load on the grounded conductor (no 277 volt loads), If we can not land EGC's on the GC bus then we should have to install an additional EGC bus. I can possibly see that in wording of NEC - but still think it is totally pointless especially in that application.

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

After all the rhetoric here, the rest can be figured out by anyone. Though you mentioned no load-side grounded conductors are needed for your applications, for those that do, I would still try to keep terminals with grounded conductors toward end where the grounded service conductor is connected and EGCs toward the opposite end, strictly as a workmanship issue.

 

[Smart $]

That depends, does the service disconnecting means have OCPD in it? I'll assume not, as otherwise the MLO panel is not service equipment, so there's nothing to discuss. So we need to check Article 250 carefully to see which items must be connected in the service disconnecting means, which items must be connected in the MLO panel, and which items can be connected in either.

For example, 250.24(A)(1) says the the grounding electrode conductor can't be landed in the MLO panel, it needs to be landed in the service disconnecting means or further upstream of it. Which is a little surprising to me.


Article 250 is rather convoluted, so I'm just trying to follow what's written. You still haven't posted anything supporting the idea that removing the main bonding jumper needs to leave the EGCs disconnected from the grounded conductor.

Cheers, Wayne

As I said earlier, keep working on that logic and eventually you'll get there... hmy:

 

[wwhitney]

As I said earlier, keep working on that logic and eventually you'll get there

Nah, the rules as written in article 250 logically permit the common situation that after removing the Main Bonding Jumper, some or all of the EGCs are still bonded to the grounded service conductor.

If you'd like a requirement that prevents that, feel free to submit a public input for 2020.

Cheers, Wayne

 

[Smart $]

Nah, the rules as written in article 250 logically permit the common situation that after removing the Main Bonding Jumper, some or all of the EGCs are still bonded to the grounded service conductor.

There's that "interpretation blindness" I referred to earlier.

 

[wwhitney]

There's that "interpretation blindness" I referred to earlier.

Comments like that do not advance the discussion, I could just as easily accuse you of "interpretation blindess".

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

Oh good, that makes it easy to resolve this discussion. Whether the grounded conductor terminal bus is fastened directly to the metal enclosure has no significance under Article 250, nothing in the article distinguishes between the two cases.

So whenever EGCs and grounded conductors are intermixed on a single terminal bus within the service disconnecting means enclosure, we'll call that terminal bus the main bonding jumper. The terminal bus will either be mounted to the metal enclosure, or there will be an EGC that bonds the enclosure to that terminal bus. Either way, this satisfies every section you've cited in this thread: 250.24(A)(1) (the GEC can land there), 250.24(A)(5), and 250.24(B).

Cheers, Wayne

 

[Smart $]

... or there will be an EGC that bonds the enclosure to that terminal bus. ...

Here's part of the problem. There is no EGC which exists entirely within the service disconnecting means enclosure. You must get your terminologies, definitions, and implicit references properly integrated into your reasoning.

You are right on the cusp but your interpretation blindness is preventing you from crossing over to the dark side. :lol: