220.4A and 300.3B applied to neutral bar mounted in overhead wireway.

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mgawatt

Member
Location
Buxton maine
First of, let me start by saying I am not young. I may have been lead into some possibly non complying practices over the last 50 YEARS which is WHY i ASK QUESTIONS.
The SCENARIO IS A 480/277V PANELBOARD WITH 3 2" CONDUITS EXTENDING VERTiCALLY ABOUT 40" into a A 10 X 10 X 48" WIREWAY WHICH is attached up tight to the finish ceiling. Now, in the past, we always considered that assembly as one big panelboard and once the cable conductors entered that wireway, one could pretty much do what one wants with them...i,e, install a grounding bar in the wireway to run all the branch circuit grounding conductors and so the same thing with an isolated neutral bar which saves counts on the conductor fill of the 40" 2' pipe to minimize conductor derating.

I have been doing it this way for well over 20 years until today when I was inspected by the senior state of Maine electrical Inspector. He states that 220.4A and 300.3b prohibit doing that and all the individual neutral conductors associated with each branch circuit must goo all the way to the grounded terminal in the main feeder panel.

Does anyone smart out there have an opinion on this. At one time, the State of Maine electrician's examaining board had issued an adoption stating that they would consider all electrical equipment on the same backboard as the feeder panel part ofthat FEEDER PANEL AND ONE COULD INSTALL THE NEUTRAL BAR WHEREVER ONE WISHED AS IT WAS NOW IN THE PANELBOARD ASSEMBLY.
 

mgawatt

Member
Location
Buxton maine
GRATITUDE FOR CLARIFICATION

GRATITUDE FOR CLARIFICATION

THANK YOU FOR THE CLARIFICATION.Are THERE ANY OTHER CODE ARTICLES YOU WOULD USE TO SUPPORT YOUR DECISION BESIDES THE 2 QUOTED?
 
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LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
STOP SHOUTING!

Please release your caps lock. It's difficult to read.

How would you route the grounded conductor from the feeder in the panel to the bus in the wireway?

Every line conductor that supplied any line-to-neutral load must be fed through the same pathway.
 

mgawatt

Member
Location
Buxton maine
Sorry about the lousy typing skills not to date me.( I was trained to type on a teletype machine). The feeder conductors enter the wireway right next to the branch circuits in the 10' x 10' 48" wireway. 3 2" conduits each 40" long then connect to the panelboard directly under the wireway.Tthe feeder conductors enter the npanelboard through the center conduit and consist of 3 250 mcm, one 2.0 mcm, and one 4 green copper grounding conductor. there was a 2 awg copper grounded conductor in the same feeder conduit up to an isiolated grounded bar in the wireway. The branch circuits are entering the 10 x 10 x 40" wireway and go to both the grounding bar and the grounded bar in the wireway. then the ungrounded conductors go down the side 2" conduyit to their respective overcurrent device. each branch circuit has it's own conductor aS IS required Bby200.4a. The difference is that the grounded conductors of the branch circuit stopped at the above wireway insulated grounded bar instead of passing down to the grounded terminal in the panelboard 40" away.
the 2/0 grounded conductor was run in the same conduit as the feeder conductors for that reason.(as well as the gounding equipm,ent conductor going to the grounding wireway in the metallic wireway.
 
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texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
THANK YOU FOR THE CLARIFICATION.Are THERE ANY OTHER CODE ARTICLES YOU WOULD USE TO SUPPORT YOUR DECISION BESIDES THE 2 QUOTED?

200.4 that prohibits this was added to the NEC in the 2011 edition. The jist of the reasoning for the change was that while this was a common practice in some areas, the code as written did not specifically prevent this and it was argued that it should not be allowed.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Tthe feeder conductors enter the npanelboard through the center conduit and consist of 3 250 mcm, one 2.0 mcm, and one 4 green copper grounding conductor. there was a 2 awg copper grounded conductor in the same feeder conduit up to an isiolated grounded bar in the wireway.

The branch circuits are entering the 10 x 10 x 40" wireway and go to both the grounding bar and the grounded bar in the wireway. then the ungrounded conductors go down the side 2" conduyit to their respective overcurrent device.
Therein lies the problem: The ungrounded and grounded conductors of each circuit must be run through the same conduit.

In other words, you have the hots routed through different conduits than the neutrals, which induces currents in the conduits.
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
Therein lies the problem: The ungrounded and grounded conductors of each circuit must be run through the same conduit.

In other words, you have the hots routed through different conduits than the neutrals, which induces currents in the conduits.

I agree with what you are saying but it is moot as the OP (unless I'm not understanding the OP) is not terminating the individual neutrals at the panelboard neutral bar which violates 200.4(A).
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I agree with what you are saying but it is moot as the OP (unless I'm not understanding the OP) is not terminating the individual neutrals at the panelboard neutral bar which violates 200.4(A).
He's talking about using a single #2 as a common neutral for all of the circuits. Code says they must land in the panel. Electricity says the hots should be in the same conduit as the common neutral.

We're not disagreeing; we're pointing out two different issues. It is okay to do a common EGC.
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
He's talking about using a single #2 as a common neutral for all of the circuits. Code says they must land in the panel. Electricity says the hots should be in the same conduit as the common neutral.

We're not disagreeing; we're pointing out two different issues. It is okay to do a common EGC.

Agreed. Just a misunderstanding.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Personally, I hope this kind of rule leads to electricians putting in more panelboards, especially in residences, over having everything be a home run. Put a (sub) panelboard on each floor so there are plenty of circuits. Put one on each end of the house too, And one in the garage.

Especially these days with the miserable AFCI requirements.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
A "column width" panel board is designed for that purpose...that is a common neutral conductor runs from the panel board to a junction box connected to the panel via an auxiliary gutter. The junction box contains a neutral bar for all of the branch circuit neutrals. 300.3(B)(4).
That application and the ones in 215.4 and 225.7(B) are the only cases where the code permits the use of a common neutral.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
200.4 that prohibits this was added to the NEC in the 2011 edition. The jist of the reasoning for the change was that while this was a common practice in some areas, the code as written did not specifically prevent this and it was argued that it should not be allowed.
That change was from a proposal that I made. The only reason was to try to clarify it common neutrals are permitted. Many AHJs were trying to use the specific permissions in 215.4, 225.7(B) and 300.3(B)(4) to prohibit the use of common neutrals in other applications. My point was that a specific permission to do something does not act to prohibit doing that something for other applications.
One of the issues was that I had an associated proposal that would define "common neutral" that was not accepted and when the change first came out, some were saying it prohibited multiwire branch circuits.
I still believe it needs to be defined as it is use in at least three articles and many electricians call the neutral of a multiwire branch circuit a common neutral.
 

mgawatt

Member
Location
Buxton maine
Thanks again for all the input. I was unaware of the 2011 NEC change per say prohibiting this pratice. I was reinspected today and passed with flying colors (after only 12 hours bringing down individual grounded conductors to panelboard grouinded terminal).
I will not make that mistake again in this lifetime. Thank you for teaching an old dog new tricks.

Now, because I am older and cantankerous, please expain to me the difference between a large panelboard with the neutral bar 6 foot away from the bus bar and physically installing an proper size grounded conductor to an isolated neutral bar as I dfid. I can tell you for a fact I have never had a problem with doing that installation for at least 20 years. One could even run the grounded conductor in the same conduit as the ungrounded conductors if that is what is bothering everyone. the conduit is non-metallic as well so there is no danger of skin current problems. I understand the code prohibits it but I still don't see the concern.
 
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kwired

Electron manager
Location
NE Nebraska
STOP SHOUTING!

Please release your caps lock. It's difficult to read.

How would you route the grounded conductor from the feeder in the panel to the bus in the wireway?

Every line conductor that supplied any line-to-neutral load must be fed through the same pathway.

Therein lies the problem: The ungrounded and grounded conductors of each circuit must be run through the same conduit.

In other words, you have the hots routed through different conduits than the neutrals, which induces currents in the conduits.
I think he had net balance of current carrying conductors in each and every raceway/wireway, just didn't land the branch neutral conductors on terminal bus at the panelboard, no inductive effects would have occurred on raceways.

A "column width" panel board is designed for that purpose...that is a common neutral conductor runs from the panel board to a junction box connected to the panel via an auxiliary gutter. The junction box contains a neutral bar for all of the branch circuit neutrals. 300.3(B)(4).
That application and the ones in 215.4 and 225.7(B) are the only cases where the code permits the use of a common neutral.
I was going to bring up "column width" panel boards - but those are a listed assembly and sort of counts as one panelboard instead of a panelboard, wireway and junction box.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I think he had net balance of current carrying conductors in each and every raceway/wireway, just didn't land the branch neutral conductors on terminal bus at the panelboard, no inductive effects would have occurred on raceways.
He mentioned running a #2 back up through the center conduit, which houses the panel feeder, and the circuit ungrounded conductors through the two side conduits; a no-no even with PVC conduit unless the KOs are joined by cuts to become one oddly-shaped opening, which would be rendered ineffective by metal locknuts.

I'm also thinking the extended neutral conductor would need to be as large as the feeder neutral (were this otherwise okay).
 

kwired

Electron manager
Location
NE Nebraska
He mentioned running a #2 back up through the center conduit, which houses the panel feeder, and the circuit ungrounded conductors through the two side conduits; a no-no even with PVC conduit unless the KOs are joined by cuts to become one oddly-shaped opening, which would be rendered ineffective by metal locknuts.

I'm also thinking the extended neutral conductor would need to be as large as the feeder neutral (were this otherwise okay).
I missed it or misunderstood. I thought he had a gutter between panel and the junction box, that should have contained all conductors involved.
 
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