Residential panel ground bars

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dm9289

Industrial Maintenance Electrician
Location
Pennsylvania
Occupation
Industrial process repair/ maintenance Electrician
In my area we are using 2017 Nec and we do not use outside disconnects. From bottom of meter socket se cable goes inside house to main breaker panel. The green ground screw is installed.
So in my thinking at this point grounds and neutrals can be installed separately on same gnd/neutral bar. In this panel the right side was neutral bar only till ground screw or bonding jumper was installed, left side was originally gnd bar only. In addition in this panel there were 2 other gnd bars one at bottom left one at top right. I was told you need to run a jumper from the neutral bar to the ground bar top right i did not understand this because i thought green screw made the entire case same potential. I was told you don't want neutral current on case but in my thinking even if you add jumper some of the current will use the case.

Please help me understand this


sPanel bond.jpg
 
The neutral can not land on any termination bar that is not connected to the neutral conductor by a wire or a bus. See 200.2(B).
The main bonding jumper (green screw) is only for equipment grounding purposes and not intended to be a conductor that normally carries current.
 
don_resqcapt19 said:
The neutral can not land on any termination bar that is not connected to the neutral conductor by a wire or a bus. See 200.2(B).
The main bonding jumper (green screw) is only for equipment grounding purposes and not intended to be a conductor that normally carries current.
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Thank you so much i am highlighting that in my book now
 
Even just having the jumper to the additional bus in this instance is not proper to land the neutral, that added bar is only listed as a grounding bus not a neutral bus. So having the neutral wire landing there is still in violation. Additionally and can't really tell from photo but if you didn't use the factory provided tapped holes to mount the grounding bus it would then need a seperate strap or conductor to bond it back to main bus unless the tap was such to engage 2 full threads of the attaching screws.
 
Fred B said:
Even just having the jumper to the additional bus in this instance is not proper to land the neutral, that added bar is only listed as a grounding bus not a neutral bus. So having the neutral wire landing there is still in violation. Additionally and can't really tell from photo but if you didn't use the factory provided tapped holes to mount the grounding bus it would then need a seperate strap or conductor to bond it back to main bus unless the tap was such to engage 2 full threads of the attaching screws.
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Its my understanding these panels are manufactured like this see HD pic. So you are saying in your view even if it is a factory installed grounding bus with a #6 jumper as shown it is still a violation. Am i reading you properly?

1650295600671.png
 
dm9289 said:
Its my understanding these panels are manufactured like this see HD pic. So you are saying in your view even if it is a factory installed grounding bus with a #6 jumper as shown it is still a violation. Am i reading you properly?
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Yes it's still a violation to land a neutral on the EGC bus even if there is a wire jumper between the two buses. The jumper doesn't stop some neutral current from flowing on the enclosure which is the problem.
 
infinity said:
Yes it's still a violation to land a neutral on the EGC bus even if there is a wire jumper between the two buses. The jumper doesn't stop some neutral current from flowing on the enclosure which is the problem.
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I spoke to Semens via a returned call. The factory installed is a ground bar they do sell extra neutral bars that fit and would require a wire type connection.
 
dm9289 said:
Its my understanding these panels are manufactured like this see HD pic. So you are saying in your view even if it is a factory installed grounding bus with a #6 jumper as shown it is still a violation.
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I don't see the jumper you mentioned.
 
dm9289 said:
At the very top picture not the home depot one there is an s shaped piece of #6 bare copper
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I don't know if that is a factory jumper or not, but in the service equipment, a wire jumper will permit you to use that equipment grounding bar for the termination of neutral conductors.
The language in 200.2(B) does not prohibit the enclosure from being a parallel path for neutral current. It only prohibits the enclosure from being the only path for neutral current.
 
That factory added ground bar even if you have a jumper cannot be used for a neutral bar.
An added neutral that might be available is isolated from the enclosure and would require a jumper. Every listed suplimental "neutral" bus bar I've found has isolation insulation that keeps bus from direct contact with enclosure. Like image below. Every other bus that is direct connected to the enclosure are listed and limited to use as grounding bus, and specify as not useable as neutral bus. Why? If they are interchangeable.
1650329468196.png
 
Fred B said:
That factory added ground bar even if you have a jumper cannot be used for a neutral bar.
An added neutral that might be available is isolated from the enclosure and would require a jumper. Every listed suplimental "neutral" bus bar I've found has isolation insulation that keeps bus from direct contact with enclosure. Like image below. Every other bus that is direct connected to the enclosure are listed and limited to use as grounding bus, and specify as not useable as neutral bus. Why? If they are interchangeable.
View attachment 2560271
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Assuming that it is in the service equipment enclosure, why can't it be used for neutrals?
 
This is how I see it. Anything downstream from the Main Service, the Grounding and Grounded buses need to be separated.
 

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  • Electrical Service Detail - Los Angeles County.pdf
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  • City of Los Angeles - Water pipe bonding, 08-03-2015.pdf
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While doing an HVAC inspection, took this picture of a Zinsco main panel.
 

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