Neutrals and ground on the wrong bus.

[Smart $]

No, no, no. That is just saying that you can't use the metal enclosure as a neutral, you have to use the buss that the neutral lands on.

I think you best reread 250.24(A)(5) and rethink your position. 250.24(B) further supports my position.

(B) Main Bonding Jumper. For a grounded system, an unspliced
main bonding jumper shall be used to connect the
equipment grounding conductor(s) and the service-disconnect
enclosure to the grounded conductor within the enclosure for
each service disconnect in accordance with 250.28.

There exists a possibility I am in error regarding my reply (post #19) to Rob's (infinity) statement (post #17) IF the tie bar can be called the main bonding jumper. I based my comment on the appearance of both right and left buses being isolated from the panel and assume the panel is bonded by a screw furnished by the manufacturer. I am viewing that screw as the MBJ.

 

[infinity]

I think you best reread 250.24(A)(5) and rethink your position. 250.24(B) further supports my position.


There exists a possibility I am in error regarding my reply (post #19) to Rob's (infinity) statement (post #17) IF the tie bar can be called the main bonding jumper. I based my comment on the appearance of both right and left buses being isolated from the panel and assume the panel is bonded by a screw furnished by the manufacturer. I am viewing that screw as the MBJ.

The tie bar just takes two sections of bus on opposite side of the panel and connects them together make them basically one bar.

 

[Smart $]

The tie bar just takes two sections of bus on opposite side of the panel and connects them together make them basically one bar.

Exactly my viewpoint. Unless the tie bar (bus) can be considered the MBJ, you cannot compliantly connect an EGC to either side per the Code sections I quoted earlier.

Panelboards like that usually have provisions to fasten one or more equipment ground terminal bars to the enclosure. The bars are either furnished with the panelboard or available for purchase separately.

 

[kwired]

Exactly my viewpoint. Unless the tie bar (bus) can be considered the MBJ, you cannot compliantly connect an EGC to either side per the Code sections I quoted earlier.

Panelboards like that usually have provisions to fasten one or more equipment ground terminal bars to the enclosure. The bars are either furnished with the panelboard or available for purchase separately.

And if the panel is not the service equipment you don't install the bonding screw and you must use the separate EGC bars.

I don't think you will find very many who are well educated in NEC that don't feel you can land an EGC on the neutral bus at the service equipment enclosure, I do see how you are arriving at your interpretation of this as well but don't agree that is what the intention is. If that is the intention I feel they need to make it a little more obvious somehow. Until then the grounded conductor and equipment grounding conductor are the same point to me at the service disconnecting means.

 

[Smart $]

... If that is the intention I feel they need to make it a little more obvious somehow. Until then the grounded conductor and equipment grounding conductor are the same point to me at the service disconnecting means.

It never fails to amaze me how experienced electricians blatantly violate Code because they believe the intent is different than the written word. While I understand how they draw these conclusions, what I most certainly do not understand is how the CMPs consistently reject proposals where clarification is needed or they and the TCC fail to discern these misinterpretations and initiate a change.

 

[jaggedben]

Though that may be acceptable to some AHJ's, it is a violation. The neutral and equipment grounding buses must be connected to opposite ends of the main bonding jumper, which the tie bar is not.

250.24(A)...

That section says you can't connect the neutral to a ground bar. But it doesn't say you can't connect an EGC to a neutral bar in an enclosure with a main bonding jumper. I'd say your point remains debatable, at best.

 

[Smart $]

That section says you can't connect the neutral to a ground bar. But it doesn't say you can't connect an EGC to a neutral bar in an enclosure with a main bonding jumper. I'd say your point remains debatable, at best.

Regardless of whether you land an EGC on a grounded conductor terminal bus or a grounded conductor on an EGC terminal bus, you have thus violated "A grounded conductor shall not be connected ... to equipment grounding conductor(s)..." [250.24(A)(5)].

 

[jaggedben]

250.142(A)

A) Supply-Side Equipment. A grounded circuit
conductor shall be permitted to ground non-current carrying
metal parts of equipment, raceways, and other
enclosures at any of the following locations:
(1) On the supply side or within the enclosure of the ac
service-disconnecting means
(2) On the supply side or within the enclosure of the
main disconnecting means for separate buildings as
provided in 250.32(B)
(3) On the supply side or within the enclosure of the
main disconnecting means or overcurrent devices of a
separately derived system where permitted by
250.30(A)( 1)

Seems pretty clear to me.

 

[infinity]

Regardless of whether you land an EGC on a grounded conductor terminal bus or a grounded conductor on an EGC terminal bus, you have thus violated "A grounded conductor shall not be connected ... to equipment grounding conductor(s)..." [250.24(A)(5)].

In the panel that is in post #3 there is only one bus for the Neutrals and EGC's (two separate sections connected together by the manufacturer) so aren't they the same in that instance?

 

[Smart $]

250.142(A)

A) Supply-Side Equipment. A grounded circuit
conductor shall be permitted to ground non-current carrying
metal parts of equipment, raceways, and otherenclosures at any of the following locations:
(1) On the supply side or within the enclosure of the ac
service-disconnecting means
(2)...

Seems pretty clear to me.

An EGC terminal bus is, but a wire-type EGC is not considered a non-current-carrying metal part within the service disconnecting means enclosure per definition:

Grounding Conductor, Equipment (EGC). The conductive
path(s) that provides a ground-fault current path and connects
normally non–current-carrying metal parts of equipment
together and to the system grounded conductor or to the
grounding electrode conductor, or both.

​

Informational Note No. 1: It is recognized that the equipment​

grounding conductor also performs bonding.​

Informational Note No. 2: See 250.118 for a list of acceptable​

equipment grounding conductors.​

And the grounded conductor(s) in the service disconnecting means enclosure is required to be connected to the non-current-carrying metal parts through the main bonding jumper [250.24(B)].

 

[Smart $]

In the panel that is in post #3 there is only one bus for the Neutrals and EGC's (two separate sections connected together by the manufacturer) so aren't they the same in that instance?

The fault in your premise is preconceiving the provided terminal buses are for both Neutrals AND EGC's. The terminal buses are only for Neutrals.

Here's a similar panel with feature callouts...

 

[infinity]

The fault in your premise is preconceiving the provided terminal buses are for both Neutrals AND EGC's. The terminal buses are only for Neutrals.

Here's a similar panel with feature callouts...

View attachment 16265

OK it's estimated that there's about 75 million single family homes in the United States and let's say 80% (60 million) have panels that are functionally identical to the one in the photo, it's your contention that all 60,000,000 are in violation because the neutrals and EGC's are intermingled on both sides of the panel which has two separate bus bars that the manufacturer connects together?

 

[SCelectrician]

Thank you all for your responses, I will post a picture of the panel in question Saturday when I get a chance to get back over there. Thanks again.

 

[Smart $]

OK it's estimated that there's about 75 million single family homes in the United States and let's say 80% (60 million) have panels that are functionally identical to the one in the photo, it's your contention that all 60,000,000 are in violation because the neutrals and EGC's are intermingled on both sides of the panel which has two separate bus bars that the manufacturer connects together?

I am contending SUSE panelboards with mixed neutrals and EGC's on the same isolated terminal bus are in violation. I have no idea how many.

 

[infinity]

I am contending SUSE panelboards with mixed neutrals and EGC's on the same isolated terminal bus are in violation. I have no idea how many.

OK fair enough I didn't want to make any assumptions.

 

[jaggedben]

The fault in your premise is preconceiving the provided terminal buses are for both Neutrals AND EGC's. The terminal buses are only for Neutrals.

Here's a similar panel with feature callouts...

View attachment 16265

The 'easily separable for subpanel applications' note seems to undermine your use of this example to make your point. The notes on that image seem to say: 'These terminal bars are for neutrals and EGCs; if you need to dedicate one of the bars to be neutral and the other EGC, take out the strap. You could pick either one to be the neutral bar and the other the ground bar since we called them 'twin neutral bars' but also clearly implied that you could use one for ground and the other for neutral if you choose.'

 

[Smart $]

The 'easily separable for subpanel applications' note seems to undermine your use of this example to make your point. The notes on that image seem to say: 'These terminal bars are for neutrals and EGCs; if you need to dedicate one of the bars to be neutral and the other EGC, take out the strap. You could pick either one to be the neutral bar and the other the ground bar since we called them 'twin neutral bars' but also clearly implied that you could use one for ground and the other for neutral if you choose.'

I have no problem with taking out the tie bar (strap) and using one bar as an EGC terminal bus and one as a neutral in an SUSE situation... but if I were to be totally nitpicky, with both bars being isolated from the enclosure, how are you going manage to use just one main bonding jumper to connect both the bar and the enclosure to the grounded conductor as required by 250.24(B)?

 

[jaggedben]

I don't buy your premise that the main bonding jumper or its location has anything to do with anything. I think what your argument is still missing is any code reference that clearly prohibits connecting an EGC to a neutral bar in a service enclosure. As for code references that clearly (to me anyway) permit doing such a thing, see 250.130 (A), as well as what I posted above.

 

[Smart $]

I don't buy your premise that the main bonding jumper or its location has anything to do with anything. I think what your argument is still missing is any code reference that clearly prohibits connecting an EGC to a neutral bar in a service enclosure. As for code references that clearly (to me anyway) permit doing such a thing, see 250.130 (A), as well as what I posted above.

If you can directly connect any EGC to the grounded conductor in the service disconnecting means enclosure, what is the purpose of the main bonding jumper and why would we need one?

 

[gndrod]

Details

Details

The neutral bus is isolated, which currently has all of the grounds on it.

This is the panel currently in use. The lug that would terminate the neutral coming from the meter has all of the grounds currently on it.

Hi SC,
From your description of a 3-wire 1 ph 200A, 240V Service Main panel board, the picture appears to be an EATON BR Renovation type load center. Without more wiring details, the panel pic you posted is a convertible 3-4 wire load center for what you describe but it is not bonded properly. The existing panel shown is unfinished and not terminated for a 3-wire nor 4-wire configuration.

The 3-wire bonding 'z' strap needs to be connected to the isolated neutral terminal bars for terminating EGC and Neutral conductors to either side bars. In a 4-wire system, the 'z' strap is still needed for this brand panel to be bonded to the right terminal bar for bonding EGC terminations while the horizontal Bonding Jumper needs to be disconnected to isolate the Neutral left side strip. Those are the two basic bonding choices without extra panel strap modifications.