Ungrounded Conductors From Same Circuit on Same Breaker?

[charlie b]

Here is an a drawing of an example charlie b posted in post #137.

Thanks for posting that. Now let me assert a couple things, with the top image in mind.

• There are parallel paths from the breaker to the loads.
• That said, wire 2 and wire 3 (as an example) are not in parallel with each other. That has been my key point all along.
• If you do put two identical wires in parallel with each other, the combined ampacity will become double the ampacity of either wire alone.
• Some members participating in this thread have repeatedly contended that the entire group of wires are "electrically joined at each end," and are therefore parallel, in the context of 310.4. But looking at this image, it is clear that I can't send twice as much current through wires 2 and 3 (again, as an example) as either wire is rated to handle on its own, because the two wires would not split that current, each taking half. That is my proof that no two wires within the ring are in parallel, in the context of 310.4

All I have been trying to say all along is this: If the ring circuit violates the NEC, the violation is not based on the 310.4 requirement for a minimum size of wires placed in parallel. The wires are not in parallel, so the minimum of 1/0 does not apply. So go find some other place in the NEC, if you wish to call this a violation.

 

[kwired]

Thanks for posting that. Now let me assert a couple things, with the top image in mind.

• There are parallel paths from the breaker to the loads.
• That said, wire 2 and wire 3 (as an example) are not in parallel with each other. That has been my key point all along.
• If you do put two identical wires in parallel with each other, the combined ampacity will become double the ampacity of either wire alone.
• Some members participating in this thread have repeatedly contended that the entire group of wires are "electrically joined at each end," and are therefore parallel, in the context of 310.4. But looking at this image, it is clear that I can't send twice as much current through wires 2 and 3 (again, as an example) as either wire is rated to handle on its own, because the two wires would not split that current, each taking half. That is my proof that no two wires within the ring are in parallel, in the context of 310.4

All I have been trying to say all along is this: If the ring circuit violates the NEC, the violation is not based on the 310.4 requirement for a minimum size of wires placed in parallel. The wires are not in parallel, so the minimum of 1/0 does not apply. So go find some other place in the NEC, if you wish to call this a violation.

But what is a conductor? NEC does not define 'conductor" One could call wire 2 and 3 plus the connector between them one conductor depending on what definition of conductor is used.

In the image one could call wires 1,2 and 3 one conductor and it is parallel with another conductor made up of 5,6 and 7. wire 4 is the connecting link for one end as well as the breaker terminal on the other end.

NEC does not specifically say this is a parallel conductor.

NEC does not specifically say this is not a parallel conductor.

NEC does not specifically mention 'parallel conductor in 310.4.

It does permit 'conductors to be connected in parallel', with rules of how it is to be done.

If current enters one point and is able to split and come back together again you have parallel paths. In the 'ring circuit' there are two paths are made up of conductors. Some parts of these conductors are connecting devices, some parts are not same length as parts in the other side therefore each side of the parallel path is not equal and current will not evenly divide.

I am not arguing whether this is allowed to be done this way or not, my point is that this arrangement does have conductors connected in parallel to each other.

Before we ever got into much discussion whether this is allowed or not the debate has turned into the whether or not there is parallel paths, and what is a conductor?

Like I said the NEC does not define 'conductor' but isn't the function of things like lugs, wire nuts, buttsplicers, compression connectors, and the like to conduct current between the other conductive items it is attached to? So wouldn't that make them conductors also? Their intended purpose certainly is not for insulating.

 

[kwired]

Lets look at 310.4 compliant conductors connected in parallel in this way.

Each separate path of the parallel paths must be kept as similar as possible so that each separate path will be same resistance and therefore carry same current.

Lets say we have a 400 amp feeder. You could run two copper 'wires' from a breaker to a splice point then run two aluminum 'wires' from the junction point to another point lets say main lugs on a panelboard. Now lets go a single copper of appropriate size from the feed thru lugs on the panelboard to a second panelboard.

At the first splice point you could either put all four 'wires' in the same connector or use two connectors with a copper and an aluminum in each one

At each of the panels each 'conductor' must have all of its 'parallels' land at the same point and they must all be same length size, or any other characteristic that will effect resistance.

From the breaker up to and including the bus in the last panel is a 400 amp conductor, made up of more than one type of conductor material.

Now lets say you run 400 amp conductor or set of conductors back to the source breaker from the last panel. Now you have a "ring circuit".

It is permitted by NEC? Maybe. Maybe not. The last conductor or set of conductors is parallel with the other path.

Maybe this was not intended to be exempt from 410.4, I have given up on trying to prove that one way or the other, but you can not tell me that there is not conductors connected in parallel.

 

[ggunn]

IMO, you guys are making this far too complicated. 310.4(A) is very clear about what it allows: you can run parallel conductors of size 1/0 and larger from one connection point to another to make it easier to handle the wires and maybe save some money. It is *not* clear and comprehensive about what it does not allow, but what rule is? When you write a rule it is not possible to imagine every possible situation that might come up.

It is like shooting fish in a barrel to come up with scenarios which will fall into a gray area of the rules and get everyone chasing their tails over the meaning of terms; I daresay you can do that with just about any Article in the code.

It begs the question: Why? Is there a point to any of this? You can argue until you are blue in the face (some of us already are) over an esoteric interpretation of a fine point which affects virtually no one, but at the end of the day you are just arguing for the joy of arguing. The answer is just not there in the simplest (Occam's razor) interpretation of the words on the page. If it's *really* important (my take is that it is not), then there are avenues to pursue to get the Code writers to address it.

Otherwise I suggest I suggest that we just agree to disagree and move on. But where's the fun in that, eh?

 

[ggunn]

At the risk of touching off another tangential debate, here's an analogy. Say that the speed limit on a stretch of hilly road is 30 mph. A police officer is going to stop and ticket a motorist traveling at 40 mph, no question. It's a clear cut case.

But what if a bicyclist, taking advantage of the hilly terrain, is able to get up to 40 mph on a downhill stretch, will the cop stop him and give him a ticket for speeding?

Probably not. The law is written to cover motor vehicle velocity, and although the cyclist is technically moving faster than the speed limit, he probably won't be cited for the violation because he does not present the threat to public safety that the speed limit law was written to address. The law, as written, neither permits nor prohibits going 40 mph on a bicycle.

The NEC (published by the NFPA) is first and foremost a fire prevention publication. If something does not represent a fire hazard, the Code may not address it. IMO, the Code is indifferent on the question of allowability of connecting receptacles in a ring configuration because it has no impact on fire safety either way.

 

[kwired]

At the risk of touching off another tangential debate, here's an analogy. Say that the speed limit on a stretch of hilly road is 30 mph. A police officer is going to stop and ticket a motorist traveling at 40 mph, no question. It's a clear cut case.

But what if a bicyclist, taking advantage of the hilly terrain, is able to get up to 40 mph on a downhill stretch, will the cop stop him and give him a ticket for speeding?

Probably not. The law is written to cover motor vehicle velocity, and although the cyclist is technically moving faster than the speed limit, he probably won't be cited for the violation because he does not present the threat to public safety that the speed limit law was written to address. The law, as written, neither permits nor prohibits going 40 mph on a bicycle.

The NEC (published by the NFPA) is first and foremost a fire prevention publication. If something does not represent a fire hazard, the Code may not address it. IMO, the Code is indifferent on the question of allowability of connecting receptacles in a ring configuration because it has no impact on fire safety either way.

If you were at a crossing road at a stop sign and saw a bicycle 200 feet away on the crossing road you may very well pull out in front of it never realizing just how fast it is traveling.

This is not a similar enough analogy to give anything to this topic. There is not a diversity of kinds of electricity traveling through power systems. And at times when there is they usually have no effect on the topic of this thread.

 

[charlie b]

But what is a conductor? NEC does not define 'conductor." One could call wire 2 and 3 plus the connector between them one conductor depending on what definition of conductor is used.

The NEC has three definitions of types of conductors, each relating to the nature of the insulation system. That makes it clear that the NEC considers a ?conductor? to essentially be a wire. But that notwithstanding, no definition of ?conductor? would allow for what you are suggesting: that wires 2 and 3 comprise a single conductor. That is because at the point of connection, a circuit element is attached. That absolutely separates wire 2 from wire 3 as being separate conductors, from the perspective of series and parallel and current paths.

In the image one could call wires 1,2 and 3 one conductor and it is parallel with another conductor made up of 5,6 and 7. wire 4 is the connecting link for one end as well as the breaker terminal on the other end.

No we can?t, for the same reason.

I am not arguing whether this is allowed to be done this way or not. . . .

Nor am I. I am just arguing that 310.4 will not answer that question.

. . . my point is that this arrangement does have conductors connected in parallel to each other.

No, it flat out does not. There are parallel paths, but there are no parallel conductors. Those are very different concepts, and you are treating them as though they were the same.

If current enters one point and is able to split and come back together again you have parallel paths. . . . the debate has turned into the whether or not there is parallel paths. . . .

It would be useful if we could stop talking about parallel paths. That phrase is irrelevant to the question of whether 310.4 (specifically, the 1/0 minimum) would be the reason that a ring circuit would violate the NEC.

. . . the debate has turned into . . . what is a conductor?

You just introduced any notion of ?what is a conductor? into this debate. I don?t think there is any way that an answer to that question is going to impact the outcome.

 

[ggunn]

If you were at a crossing road at a stop sign and saw a bicycle 200 feet away on the crossing road you may very well pull out in front of it never realizing just how fast it is traveling.

This is not a similar enough analogy to give anything to this topic. There is not a diversity of kinds of electricity traveling through power systems. And at times when there is they usually have no effect on the topic of this thread.

Heavy sigh. I knew I was taking a risk by going abstract.

The similarity is not in the minutiae of the analogy, but in the end result, which is that the Code is a set of rules to apply to specific cases for a specific purpose, which is to reduce the risk of fire (and injury, of course). Yes, you can come up with a scenario which has details in common with conditions covered by a section of the Code, but that doesn't necessarily mean that the Code takes a position one way or the other on it. If it doesn't present a fire or safety hazard, the Code may be indifferent to it.

As to analogies in general, they are fables to illustrate a point, nothing more. One of my favorites is "rearranging deck furniture on the Titanic" to illustrate how focusing on minutiae can obscure one's view of the Big Picture. Does the validity of the analogy mean that one cannot imagine a scenario where a strategically placed deck chair might have influenced the outcome of that disaster? Of course not.

 

[Smart $]

The NEC has three definitions of types of conductors, each relating to the nature of the insulation system. That makes it clear that the NEC considers a ?conductor? to essentially be a wire. But that notwithstanding, no definition of ?conductor? would allow for what you are suggesting: that wires 2 and 3 comprise a single conductor. That is because at the point of connection, a circuit element is attached. That absolutely separates wire 2 from wire 3 as being separate conductors, from the perspective of series and parallel and current paths.
No we can?t, for the same reason.
Nor am I. I am just arguing that 310.4 will not answer that question.
No, it flat out does not. There are parallel paths, but there are no parallel conductors. Those are very different concepts, and you are treating them as though they were the same.
It would be useful if we could stop talking about parallel paths. That phrase is irrelevant to the question of whether 310.4 (specifically, the 1/0 minimum) would be the reason that a ring circuit would violate the NEC.
You just introduced any notion of ?what is a conductor? into this debate. I don?t think there is any way that an answer to that question is going to impact the outcome.

Late joining and didn't read but a few of the posts, but here's my take on what I have surmised...

I agree with you in that a ring circuit is not comprised of parallel conductors, as in the OP case, so is not subject to parallel conductor requirements.

The violation could be 300.3(B) Conductors of the Same Circuit by having two paths for current to each load on the circuit while not being in the same raceway, cable, etc.... but 300.3(B)(3) provides an out for NM wiring.

 

[ggunn]

Late joining and didn't read but a few of the posts, but here's my take on what I have surmised...

I agree with you in that a ring circuit is not comprised of parallel conductors, as in the OP case, so is not subject to parallel conductor requirements.

The violation could be 300.3(B) Conductors of the Same Circuit by having two paths for current to each load on the circuit while not being in the same raceway, cable, etc.... but 300.3(B)(3) provides an out for NM wiring.

I agree as well. We are not saying that the NEC does not contain language somewhere which addresses the ring circuit at the base of this "debate", only that 310.4(A) is not pertinent.

 

[Smart $]

I agree as well. We are not saying that the NEC does not contain language somewhere which addresses the ring circuit at the base of this "debate", only that 310.4(A) is not pertinent.

I understood that going in to my post.

310.4(A) would be pertinent to conductors installed in parallel, for which it is noted that they be electrically joined at both ends. Conductors of a ring circuit having at least three wiring segments are not joined at both ends. They are only joined at one end.

 

[ggunn]

I understood that going in to my post.

310.4(A) would be pertinent to conductors installed in parallel, for which it is noted that they be electrically joined at both ends. Conductors of a ring circuit having at least three wiring segments are not joined at both ends. They are only joined at one end.

That was the crux of the argument. Some of our esteemed colleagues insisted that the two conductors feeding the ring are electrically connected at both ends since there is a path through conductors between the points where they touch the ring. I hasten to add that that is an opinion I do not share.

 

[Smart $]

That was the crux of the argument. Some of our esteemed colleagues insisted that the two conductors feeding the ring are electrically connected at both ends since there is a path through conductors between the points where they touch the ring. I hasten to add that that is an opinion I do not share.

The actual word used here, and key to the interpretation, is "joined". This infers (since the NEC does not define the term) the ends must have a physically close relationship, using commonly accepted electrical joining methods. A jumper or other conductor is not a common means of joining the ends of two other wires, as that would be considered as two splices (and two joinings).

 

[ggunn]

The actual word used here, and key to the interpretation, is "joined". This infers (since the NEC does not define the term) the ends must have a physically close relationship, using commonly accepted electrical joining methods. A jumper or other conductor is not a common means of joining the ends of two other wires, as that would be considered as two splices (and two joinings).

You mean "implies" rather than "infers", I believe, but you are preaching to the choir.

 

[Smart $]

You mean "implies" rather than "infers", I believe, ...

No, I meant "infers". Similar meanings, but "infers" is the better term here, IMO.

 

[charlie b]

No, I meant "infers". Similar meanings, but "infers" is the better term here, IMO.

No, you meant "implies." Their meanings are not at all similar. The person speaking (or writing) does the implying. The person hearing (or reading) does the inferring.

 

[cowboyjwc]

No, you meant "implies." Their meanings are not at all similar. The person speaking (or writing) does the implying. The person hearing (or reading) does the inferring.

Then I'm inferring that he was implying that he meant inferring....or I mean that, he....no he.....I prefer not to infer any further.:happysad:

 

[iwire]

You mean "implies" rather than "infers", I believe, but you are preaching to the choir.

No, I meant "infers". Similar meanings, but "infers" is the better term here, IMO.

No, you meant "implies." Their meanings are not at all similar. The person speaking (or writing) does the implying. The person hearing (or reading) does the inferring.

Then I'm inferring that he was implying that he meant inferring....or I mean that, he....no he.....I prefer not to infer any further.:happysad:

Just stopped by to see how this thread was doing, I think I will back on out of here ........... :lol:

 

[chris kennedy]

Just stopped by to see how this thread was doing, I think I will back on out of here ........... :lol:

I thought I layed this one to rest in post #3???:blink::happyno:

 

[Smart $]

No, you meant "implies." Their meanings are not at all similar. The person speaking (or writing) does the implying. The person hearing (or reading) does the inferring.

Here's Merriam Webster Collegiate Dictionary's entry for both words:

in?fer
Pronunciation: in-'fər
Function: verb
Inflected Form: in?ferred ; in?fer?ring
Etymology: Middle French or Latin; Middle French inferer, from Latin inferre, literally, to carry or bring into, from in- + ferre to carry ― more at BEAR
Date: 1528


transitive verb
1 : to derive as a conclusion from facts or premises <we see smoke and infer fire ― L. A. White> ― compare IMPLY
2 : GUESS, SURMISE <your letter⋯allows me to infer that you are as well as ever ― O. W. Holmes †1935>
3 a : to involve as a normal outcome of thought b : to point out : INDICATE <this doth infer the zeal I had to see him ― Shakespeare> <another survey⋯infers that two-thirds of all present computer installations are not paying for themselves ― H. R. Chellman>
4 : SUGGEST, HINT <are you inferring I'm incompetent?>
intransitive verb : to draw inferences <men⋯have observed, inferred, and reasoned⋯to all kinds of results ― John Dewey>
–in?fer?able also in?fer?ri?ble \in-'fər-ə-bəl\ adjective
–in?fer?rer \-'fər-ər\ noun
synonyms INFER, DEDUCE, CONCLUDE, JUDGE, GATHER mean to arrive at a mental conclusion. INFER implies arriving at a conclusion by reasoning from evidence; if the evidence is slight, the term comes close to surmise <from that remark, I inferred that they knew each other>. DEDUCE often adds to INFER the special implication of drawing a particular inference from a generalization <denied we could deduce anything important from human mortality>. CONCLUDE implies arriving at a necessary inference at the end of a chain of reasoning <concluded that only the accused could be guilty>. JUDGE stresses a weighing of the evidence on which a conclusion is based <judge people by their actions>. GATHER suggests an intuitive forming of a conclusion from implications <gathered their desire to be alone without a word>.
usage Sir Thomas More is the first writer known to have used both infer and imply in their approved senses (1528). He is also the first to have used infer in a sense close in meaning to imply (1533). Both of these uses of infer coexisted without comment until some time around the end of World War I. Since then, senses 3 and 4 of infer have been frequently condemned as an undesirable blurring of a useful distinction. The actual blurring has been done by the commentators. Sense 3, descended from More's use of 1533, does not occur with a personal subject. When objections arose, they were to a use with a personal subject (now sense 4). Since dictionaries did not recognize this use specifically, the objectors assumed that sense 3 was the one they found illogical, even though it had been in respectable use for four centuries. The actual usage condemned was a spoken one never used in logical discourse. At present sense 4 is found in print chiefly in letters to the editor and other informal prose, not in serious intellectual writing. The controversy over sense 4 has apparently reduced the frequency of use of sense 3.



? 2005 Merriam-Webster, Incorporated

im?ply
Pronunciation: im-'plī
Function: transitive verb
Inflected Form: im?plied ; im?ply?ing
Etymology: Middle English emplien, from Anglo-French emplier to entangle ― more at EMPLOY
Date: 14th century

1 obsolete : ENFOLD, ENTWINE
2 : to involve or indicate by inference, association, or necessary consequence rather than by direct statement <rights imply obligations>
3 : to contain potentially
4 : to express indirectly <his silence implied consent>
synonyms see SUGGEST
usage see INFER



? 2005 Merriam-Webster, Incorporated