Neutral on Ground bus

[Daja7]

I need the code article covering the following senario.

Customers home has a panel that is heating up and burning the plastic insulator on the neutral bus. When I checked it out I found that the neutral conductor on the service entrance cable was terminated on the ground bus attached to the can. the neutral bus was then bonded via bond screw to the can, thus useing the can as the neutral conductor. The bond screw was slightly loose so the screw was carrying the unbalance load and arcing to the point of heating and burning. I replaced the panel guts and terminated the neutral on the neutral lug as it should be. problem solved. The home owner wants to pursue this with the inspection department as this installation passed final inspection. (new home) I for some reason cannot find the appropriate code article for this.
Thanks
Daja7

 

[Dennis Alwon]

Look at 200.2(B). Unfortunately this is new to the 2008 code so.... Good luck

200.2(B) Continuity. The continuity of a grounded conductor shall not depend on a connection to a metallic enclosure, raceway, or cable armor.

 

[LEO2854]

I need the code article covering the following senario.

Customers home has a panel that is heating up and burning the plastic insulator on the neutral bus. When I checked it out I found that the neutral conductor on the service entrance cable was terminated on the ground bus attached to the can. the neutral bus was then bonded via bond screw to the can, thus useing the can as the neutral conductor. The bond screw was slightly loose so the screw was carrying the unbalance load and arcing to the point of heating and burning. I replaced the panel guts and terminated the neutral on the neutral lug as it should be. problem solved. The home owner wants to pursue this with the inspection department as this installation passed final inspection. (new home) I for some reason cannot find the appropriate code article for this.
Thanks
Daja7

Boy they did that in a brand new house?

What state do you live in?

Welcome to the forum

 

[Daja7]

Virginia,
Original home owner wired the home. (he is an electrician). He never lived in it and the new owner experienced the problem. The thing that bothers me is the inspector that passed this. it is not an obsure thing.

 

[kwired]

Virginia,
Original home owner wired the home. (he is an electrician). He never lived in it and the new owner experienced the problem. The thing that bothers me is the inspector that passed this. it is not an obsure thing.

My guess is inspector did not look at it at all or did so in a rush and maybe missed things.

People make mistakes, but if both the installer and inspector were doing their job well it is not likely to get left that way.

Depending on the design of the panel this could be easy to overlook. There are several out there that have a split neutral that runs on each side of the breaker mounting rails with a jumper bar in between them. I have seen people remove the bar and make one side neutrals and the other side grounds, if that is what was done and you don't pay very close attention I can see this mistake being made easily.

On a service panel there is no point in removing the jumper bar.
I don't know if the manufacturers intend to remove this bar. I never do, but I have seen it done.

 

[Daja7]

In this case there is no way to mistake it. the ground bar is completely independant of the neutral ( I know the type you are talking about.) It is a seperate bar mounted to the panel can. The neutral lug was left empty.
You never remove the jumper as long as this is the first means of disconnect. if the disconnect is seprate and feeds the panel then you must seperate as the bond to neutral is done in the first pointof disconnect.

Either way I am still looking for the code that covers this.

 

[roger]

In this case there is no way to mistake it. the ground bar is completely independant of the neutral ( I know the type you are talking about.) It is a seperate bar mounted to the panel can. The neutral lug was left empty.
You never remove the jumper as long as this is the first means of disconnect. if the disconnect is seprate and feeds the panel then you must seperate as the bond to neutral is done in the first pointof disconnect.

Either way I am still looking for the code that covers this.

Did you read the article section Dennis posted?

Roger

 

[Chamuit]

I don't have either of my books here right now. Basically it wasn't installed as listed.

 

[ceb58]

The home owner wants to pursue this with the inspection department as this installation passed final inspection. (new home) I for some reason cannot find the appropriate code article for this.
Thanks
Daja7

Unfortunately, the HO will be wasting his time.

 

[Daja7]

Several localities in VA including the one I am dealing with are still using 2005 code so the 2008 code will not suffice. The 200.2B is not in 2005.

I know it is just under my nose and i will find it eventually.

 

[brian john]

Several localities in VA including the one I am dealing with are still using 2005 code so the 2008 code will not suffice. The 200.2B is not in 2005.

I know it is just under my nose and i will find it eventually.

I am an EC in Virginia, and have been involved in a similar few cases (commercial not residential) and to be polite, they are WASTING their time, going after the inspection dept. But if they have time, go for it.

 

[zbang]

(he is an electrician)

Allow me to disagree with that.

 

[roger]

Several localities in VA including the one I am dealing with are still using 2005 code so the 2008 code will not suffice. The 200.2B is not in 2005.

I know it is just under my nose and i will find it eventually.

Okay, that being the case, the enclosure is not a conductor, see 110.5

110.5 Conductors.
Conductors normally used to carry current shall be of copper unless otherwise provided in this Code. Where the conductor material is not specified, the material and the sizes given in this Code shall apply to copper conductors. Where other materials are used, the size shall be changed accordingly.

The steel cabinet is not listed in 310.13 as a conductor nor is it listed in any of the Tables in 310, therefor I don't think it is a conductor intended to normally carry current as far as the NEC is concerned.

Roger

 

[dkidd]

The Code was changed through the following ROP (although renumbered in the ROC):

5-90 Log #3389 NEC-P05 Final Action: Accept
(250.14 (New) )
____________________________________________________________
Submitter: Frederic P. Hartwell, Hartwell Electrical Services, Inc.
Recommendation: Insert a new Section 250.14 as follows:
250.14 Continuity of Grounded Conductors. The continuity of a grounded
conductor shall not depend on a connection to a metallic enclosure, raceway, or
cable armor.
Substantiation: There are instances where a grounded conductor is permitted
to be connected to a metallic enclosure, as in the case of a main bonding
jumper installed within service equipment. If that service equipment supplies a
downstream panel that includes grounded circuits, the feeder will include a
grounded circuit conductor. Nothing in the present NEC prohibits the unsound
practice of terminating that grounded circuit conductor on an equipment
grounding terminal on a separate equipment grounding busbar within the
service equipment enclosure. The grounded conductor termination meets all the
restrictions in 250.24 because it occurs within the service equipment. The wire
or busbar limitation in 250.24(A)(4) addresses grounding electrode conductor
connections, not this problem. No rules in Article 200 nor 300.13 address this
problem either.
Nevertheless, under the conditions stated, a metal enclosure would now be
employed as a grounded circuit conductor, with the circuit path running over
the enclosure between the termination and the main bonding jumper. It is
highly doubtful that what is essentially an equipment grounding connection
would function as intended after it carries routine current, perhaps in the
hundreds of amperes, over the life of the installation. This practice stands on its
head the outstanding work done by CMP 5 over recent code cycles to fully
divorce equipment grounding connections from applications that routinely
carry load current. Routine load currents on grounded circuit conductors should
be confined to conductors recognized in Article 310, or busbars, etc. This
practice must be clearly prohibited. This proposal locates the prohibition in Part
I because it is a potential issue any time a grounded/grounding interconnection
is permitted within an enclosure, including 250.30(A)(1) and 250.32(B)(2).
Panel Meeting Action: Accept

 

[jumper]

Several localities in VA including the one I am dealing with are still using 2005 code so the 2008 code will not suffice. The 200.2B is not in 2005.

I know it is just under my nose and i will find it eventually.

VA has a Uniform Statewide Building Code, all localities should be on 2005.

 

[roger]

The Code was changed through the following ROP (although renumbered in the ROC):

5-90 Log #3389 NEC-P05 Final Action: Accept
(250.14 (New) )
____________________________________________________________
Submitter: Frederic P. Hartwell, Hartwell Electrical Services, Inc.
Recommendation: Insert a new Section 250.14 as follows:
250.14 Continuity of Grounded Conductors. The continuity of a grounded
conductor shall not depend on a connection to a metallic enclosure, raceway, or
cable armor.
Substantiation: There are instances where a grounded conductor is permitted
to be connected to a metallic enclosure, as in the case of a main bonding
jumper installed within service equipment. If that service equipment supplies a
downstream panel that includes grounded circuits, the feeder will include a
grounded circuit conductor. Nothing in the present NEC prohibits the unsound
practice of terminating that grounded circuit conductor on an equipment
grounding terminal on a separate equipment grounding busbar within the
service equipment enclosure. The grounded conductor termination meets all the
restrictions in 250.24 because it occurs within the service equipment. The wire
or busbar limitation in 250.24(A)(4) addresses grounding electrode conductor
connections, not this problem. No rules in Article 200 nor 300.13 address this
problem either.
Nevertheless, under the conditions stated, a metal enclosure would now be
employed as a grounded circuit conductor, with the circuit path running over
the enclosure between the termination and the main bonding jumper. It is
highly doubtful that what is essentially an equipment grounding connection
would function as intended after it carries routine current, perhaps in the
hundreds of amperes, over the life of the installation. This practice stands on its
head the outstanding work done by CMP 5 over recent code cycles to fully
divorce equipment grounding connections from applications that routinely
carry load current. Routine load currents on grounded circuit conductors should
be confined to conductors recognized in Article 310, or busbars, etc. This
practice must be clearly prohibited. This proposal locates the prohibition in Part
I because it is a potential issue any time a grounded/grounding interconnection
is permitted within an enclosure, including 250.30(A)(1) and 250.32(B)(2).
Panel Meeting Action: Accept

The problem is in post #10, the ROP is for the 2008 which Dennis posted in post #2

Roger

 

[dkidd]

I admit that there is nothing in the 2005 Code to prohibit it. I posted Mr. Hartwell's ROP to show that.

"Nothing in the present NEC prohibits the unsound
practice of terminating that grounded circuit conductor on an equipment
grounding terminal on a separate equipment grounding busbar within the
service equipment enclosure."

Just because it is not yet in effect in the location does not mean it doesn't address an identified problem.

 

[roger]

Just because it is not yet in effect in the location does not mean it doesn't address an identified problem.

And I agree 100% that it does address the topic of this thread but, future codes can't be enforced either.

Roger

 

[Dennis Alwon]

A future codes can't be enforced either.
Roger

And that is it in a nutshell. If it wasn't illegal when installed then give it up. You fixed the problem and the HO will just have to eat the expense.

 

[rickg]

Roger & another poster are correct.. 110.3B, & it is not new. The installer must follow mfg instructions. I think it is a safe bet that those instructions will indicate where the GROUNDED (neutral) conductors are allowed to terminate, (neutral buss only) and where the EQUIPMENT GROUNDING conductors can terminate (neutral buss & the additional equipment ground buss).
I have seen this type of installation numerous times. Some electricians cannot understand why neutrals do not go on a ground buss. I recently saw one where the green bond screw was black because of the poor connection. Just my 2 cents.
Rick