Ungrounded Conductors From Same Circuit on Same Breaker?

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cowboyjwc said:
Your picture doesn't show up in the quote, but suppose you just looped the wire around the screws from the breaker and then back to the breaker, then isn't it just one wire and not parralleled?
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If you went from the breaker to the outlet and then back to the breaker, then it would be covered by the section and because the wire is smaller than 1/0, disallowed by it. Whether the wire is physically cut or not is irrelevant.
 
ptonsparky said:
What happened to Charlies post that went like this:

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This is not a "parallel wire" situation. You do not have two (or more) wires connected to each other at both ends.

Let us call the attachment point (for the ungrounded conductor) on the breaker "Point 1." The point of attachment on the first outlet (a receptacle, according to the OP) will be "Point 2." The point of attachment on the next outlet (a light) is "Point 3." Let's say the point of attachment on the last outlet is "Point 7."
? I have a wire whose two points of attachment are Point 1 and Point 2. I do not have any other wires connected to _both of_ those two points.
? I have a wire whose two points of attachment are Point 2 and Point 3. I do not have any other wires connected to _both of_ those two points.
? I have a wire whose two points of attachment are Point 3 and Point 4. I do not have any other wires connected to _both of_ those two points.
? I have a wire whose two points of attachment are Point 7 and Point 1. I do not have any other wires connected to _both of_ those two points.
? In no case do I have two or more wires that have the same left-hand attachment point and the same right hand attachment point.
? Therefore, no two wires are in parallel.

It is his post, I just had to copy it from an email.

I also tend to agree with him FWIW. The ring circuit as described does not meet the qualifications of a parallel circuit.
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Labeling of the points is subjective. At one point (which could be any point) both sides meet and there are several lengths in between that are different and several load imbalances at different times.
 
ggunn said:
What are the circles? What if there are an even number of connections? Does it make any difference if anything is plugged into any of the outlets? Is the length of the wires a consideration?

This is all well and good, but unless the conductors to the breaker both connect to the same outlet, this section of the Code does not address it.
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Lights or any other outlet you want (I was in a hurry). It doesn't matter how many outlets the point is really to show that it is really parallel because it originates from the same source and at some point (you pick one) the two sides meet. That is the definition of parallel. Although in this case the parallel run violates the code due to wire size, length of each side of run, etc.

cowboyjwc said:
Your picture doesn't show up in the quote, but suppose you just looped the wire around the screws from the breaker and then back to the breaker, then isn't it just one wire and not parralleled?
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Electrically that makes no difference
 
Electron_Sam78 said:
Labeling of the points is subjective. At one point (which could be any point) both sides meet and there are several lengths in between that are different and several load imbalances at different times.
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If you looped it, that's not true. Both sides would be equal, because the cent of the run is the center of the run no matter what. And just to clarify, I'm talking about one continuous run, not two seperate.
 
cowboyjwc said:
If you looped it, that's not true. Both sides would be equal, because the cent of the run is the center of the run no matter what. And just to clarify, I'm talking about one continuous run, not two seperate.
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Suppose I loop a 3/0 copper wire from point A to point B and back to point A. At point B I tap off the loop to a lug with the proper size wire. Is this wire parallel or not. Assuming the length is equal at the tap is this conductor only rated for 200 amps or 400 amps?
 
This has certainly become a murky discussion. Let me add how I see it. If we lay out two black wires and two white wires and join the two ends of each color to a receptacle while joining the other ends to the breaker and the neutral bar respectively, then we have created parallel wiring (clearly?). Now if somewhere between the panel and the terminal outlet, we nick off some insulation on one black and one white wire and connect another receptacle, do we not still have a parallel wiring situation? We could repeat this last procedure. Why is this so controversial?
 
The NEC asks if the conductors are electrically joined forming a single conductor. A ring network provides two distinct paths.
 
cowboyjwc said:
If you looped it, that's not true. Both sides would be equal, because the cent of the run is the center of the run no matter what. And just to clarify, I'm talking about one continuous run, not two separate.
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Yes it would still be true in a loop because the loop is a parallel path to the device. The center is the center, yes, but if running each side of the loop all over different directions to different outlets the average joe electrician wouldn't be able to find it. Even if there were 3 outlets on each side and a "center" connecting outlet, that wouldn't be the center of the circuit electrically speaking when taking into consideration the resistance of the wire.

This debate is kinda fun but really the code sections dealing with paralleling wire deal with protection of the circuit especially from overload. The reason to keep the paralleled conductors the same length and terminated in the same way is to keep the resistance of each conductor the same so that each will have an equal amount of load on it and not overload one side. This is because the usual reason for parallel runs is to use multiple smaller wire for bigger ampacity loads. In this case, even though the loop is technically a parallel run, each side of the loop is protected at it's ampacity unlike the aforementioned paralleling used for supplying larger rated loads than a single conductor could handle. As to whether or not this is allowed by the code I seem to think not but I'm not dead set on that
 
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Electron_Sam78 said:
Yes it would still be true in a loop because the loop is a parallel path to the device. The center is the center, yes, but if running each side of the loop all over different directions to different outlets the average joe electrician wouldn't be able to find it. Even if there were 3 outlets on each side and a "center" connecting outlet, that wouldn't be the center of the circuit electrically speaking when taking into consideration the resistance of the wire.

This debate is kinda fun but really the code sections dealing with paralleling wire deal with protection of the circuit especially from overload. The reason to keep the paralleled conductors the same length and terminated in the same way is to keep the resistance of each conductor the same so that each will have an equal amount of load on it and not overload one side. This is because the usual reason for parallel runs is to use multiple smaller wire for bigger ampacity loads. In this case, even though the loop is technically a parallel run, each side of the loop is protected at it's ampacity unlike the aforementioned paralleling used for supplying larger rated loads than a single conductor could handle. As to whether or not this is allowed by the code I seem to think not but I'm not dead set on that
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I definately say the "ring" circuit contains parallel elements in it. I can't understand why some do not want to see it that way. Current only flows in two types of paths, series or parallel. I don't think NEC allows this per 310.4
 
If you had 2 sets of wires run to every outlet mentioned in the OP (recep-light-recep-light-recep) and then back to breaker, I would agree that these are in parallel. But that's not the case. Simply put, you have a parallel circuit but not parallel conductors.
 
jim dungar said:
Which ones of your conductors are joined in order to form a single conductor?
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all of them.

Little Bill said:
If you had 2 sets of wires run to every outlet mentioned in the OP (recep-light-recep-light-recep) and then back to breaker, I would agree that these are in parallel. But that's not the case. Simply put, you have a parallel circuit but not parallel conductors.
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You have segments of conductors but electrically they are joined together and are essentially one. You don't join them with resistors do you, and you try to make good connections so there is no resistance don't you?

What are basic electrical circuit components. Conductors, insulators, resistors, inductors, capacitors.

Put devices in the circuit and what you have is conductors surrounded by insulator. You do not have resistors, inductors, or capacitors.

Everyone is getting stuck on calling an individual length of 'wire' a conductor. When connecting it to other individual conductive components you are extending the conductor.

When making a 310.4 compliant parallel conductor you are just being more particular at making the resistance of the two parts of the 'conductor' the same.
You must also remember that whatever you join the two 'wires' together with are part of the 'parallel conductor', otherwise they will never become 'one conductor'.
 
kwired said:
You don't join them with resistors do you, and you try to make good connections so there is no resistance don't you?
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Yes, you do. Every piece of wire is a resistor.

310.4 is written to address a very specific case, that of running parallel conductors that are joined at both ends in order to reduce resistance and make pulling through conduit easier. In those cases, the ampacity of a single conductor is insufficient to carry the current in the circuit, so the article is written to ensure that no conductors are overloaded.

It doesn't attempt to address every possible wiring configuration which could be construed as a parallel connection, and IMO trying to interpret it to cover this "ring" connection method is a misapplication of the Code.
 
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ggunn said:
It doesn't attempt to address every possible wiring configuration which could be construed as a parallel connection, and IMO trying to interpret it to cover this "ring" connection method is a misapplication of the Code.
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And I agree.

The fact is, joining wires that are sized for the OCP in a loop or ring does not create any problems, and even though it is probably not by design and not started at the breaker, I would bet that most large commercial buildings have a good number of loops or rings due to the many people pulling wire and making connections in j boxes.

With that said, conductors in a ring or loop will operate cooler and more efficiently and IMO that is desirable.

Roger
 
roger said:
And I agree.

The fact is, joining wires that are sized for the OCP in a loop or ring does not create any problems, and even though it is probably not by design and not started at the breaker, I would bet that most large commercial buildings have a good number of loops or rings due to the many people pulling wire and making connections in j boxes.

With that said, conductors in a ring or loop will operate cooler and more efficiently and IMO that is desirable.

Roger
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Thank you Roger, very well put. That's kind of what I was getting at. You run parallel conductors in order to get more ampacity out of smaller wire, this is not the case. He's not running two number twelves and saying that it's good for 40 amps, he's running two number twelves and saying that it's good for 20 amps.

Seems like a waste of time and wire to me, but I still don't see a code violation. And to claify once again and to maybe even give in a little, while it may be run in parallel he's not calling it parallel conductors and is not trying to use it that way.
 
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