Landing Neutral in Service Panel

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hill900505

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Hi guys! For a 200A service panel with neutral bar and ground bar bonded through a green screw, is it compliant to land branch circuit neutral onto the EGC bar? It seems that we can land the EGC to the neutral bar in this scenario.
 
hill900505 said:
Hi guys! For a 200A service panel with neutral bar and ground bar bonded through a green screw, is it compliant to land branch circuit neutral onto the EGC bar? It seems that we can land the EGC to the neutral bar in this scenario.
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I will wait for the experts on code because I don't remember where but in my experience, no. I have never dressed a panel mixing ground and neutral and they were typically bonded.

Sent from my LG-V520 using Tapatalk
 
hill900505 said:
Hi guys! For a 200A service panel with neutral bar and ground bar bonded through a green screw, is it compliant to land branch circuit neutral onto the EGC bar? It seems that we can land the EGC to the neutral bar in this scenario.
Click to expand...
No, that bonding screw and the cabinet will end up carrying neutral current if you landed a neutral conductor on the EGC bar.

200.2(B) prohibits this.
 
hill900505 said:
Hi guys! For a 200A service panel with neutral bar and ground bar bonded through a green screw, is it compliant to land branch circuit neutral onto the EGC bar? It seems that we can land the EGC to the neutral bar in this scenario.
Click to expand...

Is it actually one bar or two?
 
Normally on a main breaker panel there is a covered jumper between the neutral and the ground bar. Then the ground bar is bonded to the enclosure.

Jim
 
If the equipment grounding bar is bonded to the neutral bar with a wire jumper it would be compliant. Not sure how you would size that jumper. I think I would size it as a supply side bonding jumper, or make it the same size as the service neutral conductor.
 
don_resqcapt19 said:
If the equipment grounding bar is bonded to the neutral bar with a wire jumper it would be compliant. Not sure how you would size that jumper. I think I would size it as a supply side bonding jumper, or make it the same size as the service neutral conductor.
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Technically I do not believe you're supposed to have a neutral on the EGC side of the main bonding jumper, which is the jumper you're describing. Objectionable current, etc.
 
jaggedben said:
Technically I do not believe you're supposed to have a neutral on the EGC side of the main bonding jumper, which is the jumper you're describing. Objectionable current, etc.
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It may or may not be the main bonding jumper. You are permitted to install a jumper from the neutral bar to an equipment grounding bar within the service equipment enclosure.
 
hill900505 said:
Hi guys! For a 200A service panel with neutral bar and ground bar bonded through a green screw, is it compliant to land branch circuit neutral onto the EGC bar? It seems that we can land the EGC to the neutral bar in this scenario.
Click to expand...

even though you see it as basically one bar, since the one is bonded to the other right there in front of you, dont shortcut. Take the time and run your grounds to the ground bar and neutrals to the neutral bar. Here is why, in my own mind, from stuff I have dealt with in other places... The current main panel may in the future become a sub panel... How, you ask? Because conditions change inside a property and with all the changes for solar and alternative energy codes etc, the need may be to put a new panel in for the solar feeds and switching from POCO to solar, etc... if the wiring is done right then all you need to do is remove the ground bonding screw between the grounding bar and the neutral bar, and run the feeds properly to the two bars from the new panel in front of it..no problems...

But if you run it with wiring all over the place then you have to trace what is neutral, what is ground, moving stuff back and forth... creating more work, and making it harder to troubleshoot as well.

I run into situations a lot where a customer wants the panel wired as sub from the house main for a while, because a relative is in the apartment, then calls and wants the panel run to its own meter... because they are renting it out... Pretty simple when I already have everything properly wired and have been doing it for the customer several times... although I have thought about installing a simple changeover switch to stop the visits back and forth..lol... however, if I do that, how do I know the bond will be done right..hahhah...
Still, pretty nice to get the call every two years to switch back and forth..on average..
 
don_resqcapt19 said:
It may or may not be the main bonding jumper. You are permitted to install a jumper from the neutral bar to an equipment grounding bar within the service equipment enclosure.
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I have difficulty imagining how that would clearly not be the main bonding jumper. The MBJ bonds the neutral to the EGC and to the service enclosure. A jumper from neutral bar to equipment grounding bar does the former, even if something else (green screw) does the latter.
 
jaggedben said:
I have difficulty imagining how that would clearly not be the main bonding jumper. The MBJ bonds the neutral to the EGC and to the service enclosure. A jumper from neutral bar to equipment grounding bar does the former, even if something else (green screw) does the latter.
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Screw only needs to be green if the screw itself is the MBJ. Otherwise the MBJ is the piece of wire ran between the grounded conductor and a lug, bar or other termination device, correct?
 
kwired said:
Screw only needs to be green if the screw itself is the MBJ. Otherwise the MBJ is the piece of wire ran between the grounded conductor and a lug, bar or other termination device, correct?
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I don't think anything in the code says what color the MBJ needs to be. Regarding your second sentence, it depends what that lug, bar, or termination device is.

Here is my point regarding the OP's question. I can imagine four scenarios in a service panel that has two separate bars.

1) One of the bars is isolated from the enclosure, and the other is not. A wire, or factory installed bar, runs between them; that is the MBJ. You are not supposed to land neutrals on the non-isolated bar, which we would call the equipment ground bar.

2) Same scenario as above, except there is also a bond (green screw, strap, whatever) on the insulated bar. This might happen if the panel was only manufactured with one bar, but someone added the non-isolated bar to gain more terminals. In this case it's debatable which object is the MBJ, but you definitely can't put a neutral on the non-isolated 'equipment ground bar' because you'll have objectionable current on the enclosure.

3) Green screw or strap or wire - i.e. MBJ - bonding the neutral bar to enclosure. Separately, a non-isolated 'equipment ground bar' is bonded only directly to the enclosure. Enclosure serves as the EGC connecting the 'ground bar' to the MBJ.

4) Two isolated bars with a factory installed insulated bar connecting them. An MBJ connects one of them to the enclosure. In this case both bars are 'neutral bars'. It is not appropriate or necessary for one to be labeled 'neutral' and the other to be labeled 'equipment ground'. (I don't think it is a violation to land an EGC on them, however.)

In none of these four scenarios is it allowed to land a neutral on something which is appropriately called an 'equipment ground bar.'
 
jaggedben said:
I have difficulty imagining how that would clearly not be the main bonding jumper. The MBJ bonds the neutral to the EGC and to the service enclosure. A jumper from neutral bar to equipment grounding bar does the former, even if something else (green screw) does the latter.
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In a panel with a screw type main bonding jumper, that screw is the main bonding jumper. Typically the EGC terminal bars connect to the panel enclosure and use the enclosure itself as part of the fault clearing path. In the service equipment, if you want to use one of the EGC terminal bars as a neutral bar, you are required to connect it to the neutral bar I don't see such a jumper as being a second main bonding jumper.
 
jaggedben said:
I don't think anything in the code says what color the MBJ needs to be. Regarding your second sentence, it depends what that lug, bar, or termination device is.
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250.28(B) requires a screw type main bonding jumper to be green.
[/quote]Here is my point regarding the OP's question. I can imagine four scenarios in a service panel that has two separate bars.

1) One of the bars is isolated from the enclosure, and the other is not. A wire, or factory installed bar, runs between them; that is the MBJ. You are not supposed to land neutrals on the non-isolated bar, which we would call the equipment ground bar.[/quote]
There is nothing in the code language that says you cannot use the EGC bar in the service equipment as a neutral bar where the EGC bar is connected to the neutral bar by a wire or a bus.
2) Same scenario as above, except there is also a bond (green screw, strap, whatever) on the insulated bar. This might happen if the panel was only manufactured with one bar, but someone added the non-isolated bar to gain more terminals. In this case it's debatable which object is the MBJ, but you definitely can't put a neutral on the non-isolated 'equipment ground bar' because you'll have objectionable current on the enclosure.
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You can land the neutrals on a non-isolated bar that is connected to the neutral bar using a wire or a bus, as long as it is within the service equipment enclosure.
3) Green screw or strap or wire - i.e. MBJ - bonding the neutral bar to enclosure. Separately, a non-isolated 'equipment ground bar' is bonded only directly to the enclosure. Enclosure serves as the EGC connecting the 'ground bar' to the MBJ.
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In that case, the enclosure would be used as the grounded conductor and that is prohibited by 200.2(B)
4) Two isolated bars with a factory installed insulated bar connecting them. An MBJ connects one of them to the enclosure. In this case both bars are 'neutral bars'. It is not appropriate or necessary for one to be labeled 'neutral' and the other to be labeled 'equipment ground'. (I don't think it is a violation to land an EGC on them, however.)
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In that case the "neutral" bar can be used for either neutrals or EGCs.
In none of these four scenarios is it allowed to land a neutral on something which is appropriately called an 'equipment ground bar.'
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There is no language in the code that supports that statement, assuming that the equipment grounding bar is connected to the neutral bar by a wire or a bus.
 
don_resqcapt19 said:
250.28(B) requires a screw type main bonding jumper to be green.
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Thanks for the correction on that.

There is nothing in the code language that says you cannot use the EGC bar in the service equipment as a neutral bar where the EGC bar is connected to the neutral bar by a wire or a bus.
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I believe in the scenario 1 I described it is objectionable current. 250.6

You can land the neutrals on a non-isolated bar that is connected to the neutral bar using a wire or a bus, as long as it is within the service equipment enclosure.
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Same.

In that case, the enclosure would be used as the grounded conductor and that is prohibited by 200.2(B)

In that case the "neutral" bar can be used for either neutrals or EGCs.
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Agreed.

There is no language in the code that supports that statement, assuming that the equipment grounding bar is connected to the neutral bar by a wire or a bus.
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Again, objectionable current. There is no reason you have to do it that way, and remedies listed in 250.6(B) are all appropriate.
 
If a 200a main-breaker panel is missing the green bonding screw, is it compliant to bond the EGC bus to the neutral bus with a #4 cu jumper?
 
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