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Neutral and grounding conductor terminations


Joe Tedesco
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REPORT ON DISCUSSIONS DURING UL MEETINGS

WITH ELECTRICAL INSPECTORS AT THE 2006 IAEI SECTION MEETINGS

Question: Panelboard neutral and grounding conductor terminations. For panelboards, how many grounding and neutral bar conductors can you use under each terminal screw?

Answer: UL Lists Panelboards under the product category “Panelboards (QEUY).â€

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Hi Joe,

Thanks for the link and IAEI info. I hope that every person who regularly visits this board understands that, in a panelboard, each neutral wire should be all alone under its own terminal screw and that this has been the case for a long, long time. (At least back to 1947, and possibly back to 1917.)

I understand that someone has been spouting misinformation on this issue on another forum. I believe that this person is incorrect. If anyone has any doubts or wants to discuss it, please post your question here.

- Jim Katen, Oregon

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Joe and Jim,

Virtually every panel I look at has multiple neutrals and grounds beneath single terminal screws. Why? Because the local AHJs say it's okay. I've taken stands a couple of times, and even cited the applicable NEC chapter and verse--cribbed from one of Jim's posts--but the peeps in charge have always shot me down. And I'm not talking about code enforcement people. I'm talking about master electricians who are licensed to perform electrical inspections.

I realize that just because those guys say it's okay, doesn't make it so. But why wouldn't they enforce the bloody rule? What's the counterpostion to the one wire per screw rule?

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Originally posted by Bain

the peeps in charge have always shot me down. And I'm not talking about code enforcement people. I'm talking about master electricians who are licensed to perform electrical inspections.

I realize that just because those guys say it's okay, doesn't make it so. But why wouldn't they enforce the bloody rule? What's the counterpostion to the one wire per screw rule?

Simple,

You're a home inspector and some electricians, plumbers, HVAC guys, and AHJ's would rather have a strand of barbed wire shoved up their bunghole before they'll ever admit that a home inspector has anything worthwhile to say.

When I run into those guys, I ask them that question directly; usually something like, "You know, I didn't write these code rules; it was a bunch of licensed electricians, electrical engineers, and probably some code guys - your guys - sitting around a table that wrote these rules, so how about helping me to understand why you're right and they're wrong.

Sometimes it brings them around, sometimes it results in a brusk, "Kiss my ass," or "F**k you, Asshole." It doesn't happen very often, so I can't say which response I experience the most - I think it's the former; they come around.

Maybe it's time for home inspectors to ask to be included in the code writing processes.

OT - OF!!!

M.

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You sum up my frustration well, Mike. It's like the idiotic gluing of ABS and PVC I asked about over the weekend. It's wrong. It shouldn't be done. But one moronic-expert looks at another moronic-expert's work and says it's okay.

Unbelievable.

Joe and Jim have forgotten more stuff about electricity than my local expert-inspectors will ever know, but they'd be shot down if they fussed about more than one neutral beneath a terminal screw.

The above paragraph contains a dangling participle, but screw it. It's only a stupid rule.

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Originally posted by Bain

Joe and Jim,

Virtually every panel I look at has multiple neutrals and grounds beneath single terminal screws. Why? Because the local AHJs say it's okay. I've taken stands a couple of times, and even cited the applicable NEC chapter and verse--cribbed from one of Jim's posts--but the peeps in charge have always shot me down. And I'm not talking about code enforcement people. I'm talking about master electricians who are licensed to perform electrical inspections.

Then you've done all you can. There's no point in arguing about a fact. It's a useless pursuit. I usually just write, "The source of my opinion is the Blah, Blah, Blah code, section xxx.x(x). Ask your electrician to state the source of his opinion." After that, I let it go.

While there's no doubt that double lugging at the neutral terminal bar is incorrect, it also isn't the end of the world. If the connections are secure, there's very little that's going to go wrong. In the rare case where I find that this is the only defect in the electrical system, I usually tell people to have it fixed the next time an electrician is present for other repairs. Most electricians would laugh at being called out just to fix some double-lugged neutrals and they'd be right to do so.

I realize that just because those guys say it's okay, doesn't make it so. But why wouldn't they enforce the bloody rule? What's the counterpostion to one wire per screw rule?

I think that, in most cases, they don't want to enforce the rule because no one's ever enforced it in the past. It's a habit. And as anyone who's tried going on a diet can attest to, human habits are powerful forces.

- Jim Katen, Oregon

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Originally posted by Bain

Joe and Jim,

Virtually every panel I look at has multiple neutrals and grounds beneath single terminal screws. Why? Because the local AHJs say it's okay. I've taken stands a couple of times, and even cited the applicable NEC chapter and verse--cribbed from one of Jim's posts--but the peeps in charge have always shot me down. And I'm not talking about code enforcement people. I'm talking about master electricians who are licensed to perform electrical inspections.

I realize that just because those guys say it's okay, doesn't make it so. But why wouldn't they enforce the bloody rule? What's the counterpostion to the one wire per screw rule?

Jim: Do you have any verification concerning the rule as far back as 1947?

Home inspectors can apply for membership on the NEC Committees and probably on NFPA 73. I have not finished with the twin neutral issue, just because I am dealing with someone who seems to think that the rule became effective only after the 2002 NEC was issued. I am sure that many know where these discussions have spilled over into 6 different threads.

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Originally posted by Joe Tedesco

Originally posted by Bain

. . . Jim: Do you have any verification concerning the rule as far back as 1947?. . .

Here's a page from the 1947 NEC. In section 1117, it says that terminals for more than one conductor have to be approved for the purpose.

Download Attachment: icon_photo.gif NEC_1947_1117a.jpg

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That phrase remained unchanged for over 20 years. Then in the 1971 edition, they changed it to, "Terminals for more than one conductors and terminals used to connect aluminum shall be of a type suitable for the purpose."

Then, in the next code cycle in 1975, they changed it back to "approved." "Terminals for more than one conductor and terminals used to connect aluminum shall be of a type approved for the purpose."

In 1981, there was an important change. "Terminals for more than one conductor and terminals used to connect aluminum shall be so identified."

The phrase hasn't changed since then.

- Jim Katen, Oregon

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Originally posted by Terence McCann

I talk about this, as the client and I are looking at the box, however I don't write it up unless I see a problem like discolored insulation. By the time we get to the box (last item I check) there's a wisp of smoke coming out of my clients ears and I already have a laundry list of major items to correct.

Thank you again Jim: I think that the word approved was the problem where some didn't know the hazards involved.

Look at this now and tell me what is going on?

http://www.nachi.org/forum/showpost.php ... stcount=18

The label is attached here too.

Image Insert:

200811771936_GE.jpg

47.44 KB

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2002 NEC 408.21 Grounded Conductor Terminations.- - Each grounded conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor.- - - Exception: Grounded conductors of circuits with parallel conductors shall be permitted to terminate in a single terminal if the terminal is identified for connection of more than one conductor.

(bold and underlining is mine)

Isn't this applicable? ie; identified for more than one.

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Originally posted by Richard Stanley

2002 NEC 408.21 Grounded Conductor Terminations.- - Each grounded conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor.- - - Exception: Grounded conductors of circuits with parallel conductors shall be permitted to terminate in a single terminal if the terminal is identified for connection of more than one conductor.

(bold and underlining is mine)

Isn't this applicable? ie; identified for more than one.

The exception only applies to circuits with parallel conductors. You're unlikely to see parallel conductors in residential wiring.

A parallel conductor is typically used where it's cheaper to run two smaller wires rather than one great big fat one. You'll occasionally see it in industrial buildings or other places that have large services. In most cases, they use separate lugs for the conductors, but they might use lugs that are rated for more than one conductor. These lugs have a hole in them that's shaped sort of like a figure 8 or a snowman.

- Jim Katen, Oregon

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Hi Randy,

They are current carrying conductors. If you place more than one under a single lug and that allows them to loosen over time and begin arcing, you can have all kinds of stuff happen. Right?

From my point of view, it's a very simple thing that folks over-complicate and that Joe and Jim are very correct to point out. The code says you can't do it, unless the panel labeling says that it's allowed such as in the photo above that is provided by Joe, so, whether it causes damage or not is irrelevant.

We see stuff every day that is done wrong but has or hasn't caused any damage; more often than not, it seems to be the latter. I might have said, "...hasn't caused any damage yet," but that's irrelevant too, because it's not a foregone conclusion that when something is done in contravention of existing regs or codes that it will cause damage.

Double-lugging neutrals on a panel bus is wrong unless the labeling on the panel allows it; that's all there is to it. There is no controversy, just some folks that don't want to write it up because they don't want to argue with an electrician or don't want to make waves, or electricians that don't want to fix it because they don't want to listen to what a home inspector says or because they've never bothered to learn their craft properly.

Write it up and be done with it. Whether you write it up to be fixed right now, or the next time an electrician is out there working on the box as Jim does, just do the right thing and write it up.

The reason that I'm so inflexible about such a little thing as this is because, even though in nearly 12 years I've been fortunate and have never had to defend myself in court, it might happen someday, and I don't want to be put in the position of admitting under questioning, while under oath, that I ever ignore stuff, even very minor stuff, that I know is wrong or is in contravention of codes and regs, for the sake of avoiding an argument or making waves. Take it from an ex-detective that has spent more time than he wants to remember being grilled by attorneys in court, that kind of admission in court will completely blow your credibility out of the water.

If it's wrong, tell 'em it's wrong and write it up. What they choose to do about it from that point on is their business.

OT - OF!!!

M.

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Originally posted by Joe Tedesco

. . . Look at this now and tell me what is going on?

http://www.nachi.org/forum/showpost.php ... stcount=18

The label is attached here too.

Image Insert:

200811771936_GE.jpg

47.44 KB

I've got a call in to GE to find out whether or not this load center really is listed to accept more than one neutral.

I'll let you know what I learn.

- Jim Katen, Oregon

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Seems simple to me when I consider the labelling on the panel plus code....

It's OK to double up grounding conductors in that panel if the conductors meet the size parameters....

It's not OK to do likewise with grounded conductors, 'cause NEC prohibits doing so.....

Unless I'm just dense today.

What's the argument for multiple neutrals?

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Originally posted by Joe Tedesco

Thanks Jim, I will wait for the reply from GE, in the meantime I would hang my hat on the 1947 rule through all of the changes, and call it as a defect and if some electrician says otherwise have them put it in writing on their letterhead.

Check this out:

http://www.lanl.gov/safety/electrical/d ... azards.ppt

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  • 2 years later...

I'm getting push back from a builder regarding the neutrals and grounds being under the same lug. I just want to be sure I'm providing the correct source for this opinion that the neutrals need to be under their own seperate lugs. Is NEC, section 408.21 the correct reference?

Thanks

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Neutrals can safely share the same terminal as a ground wire, but two neutrals ought not to share the same terminal.

Jim,

That is a new concept to me. What is your source? I don't read that into this cite:

"NEC 408.21 Grounded Conductor Terminations. "Each grounded conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor."

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