3 way current carrying conductor

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Little Bill said:
But they are NOT electrically joined at both ends. One conductor starts at the source and the other starts at a switch. That would make them "miss the boat" in two ways.
1.) not electrically joined
2.) not the same length
At least figure 6 is that way. Can't see all of figure 5, it just shows it going back towards the panel.

Also, IMO, electrically joined would mean constantly joined. With a switch they are not joined at all times. Maybe the section could be written more clearly but I think we all know what the intent was for parallel circuits.
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They are still conductors in parallel to one another, they just have more then minimum conductor size that is in violation with 310.10(H).

We have debated the parallel conductor thing here many times for certain situations usually involving control schemes, not necessarily control wiring, but any power control scheme that has an "or" function in it's design may cause questions with parallel conductors here.

I think NEC needs to clarify whether they intend 310.10(H) to apply to any possible parallel conductor situation or just for when conductors are joined together to effectively make a higher current carrying capacity conductor out of them. Don't tell me to submit a "public input" formerly known as a change proposal, because I don't know what they intend this to apply to in the first place. That needs to be known before one can actually make a valid proposal IMO. I guess maybe you sent two public input proposals one for each side of the fence and hope they consider whichever one applies and reject the other?
 
iwire said:
They are electrically joined, at each end. Just not physically or directly.



The fact the conductors are not the same length does not determine if they electrically in parallel or not.
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Our interpretation of this section is made very difficult by the fact that we want to allow the use of a snap switch to bypass a photocell or timer but do not want to allow the use of a British standard ring circuit based on the same single rule.
 
What I want or don't want to do has nothing to do with how I interpret it.

However the exceptions to the rule make clear to me how the CMP interprets it.
 
iwire said:
What I want or don't want to do has nothing to do with how I interpret it.

However the exceptions to the rule make clear to me how the CMP interprets it.
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I, for one, really want to be able to use the various switching methods that result in load current traveling in two or more parallel #12 or #14 gauge paths, but, once faced with 310.10(H), as written, and crawling around in its language, I have had to stop doing such in new installations.
 
iwire said:
They are electrically joined, at each end. Just not physically or directly.



The fact the conductors are not the same length does not determine if they electrically in parallel or not.
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I didn't say they weren't running parallel. What I said was they "miss the boat" in terms of being parallel per the requirements/definitions in the code. Which say they have to be electrically joined at both ends & be the same length. Figure 6 is neither. One conductor starts at the source and the other starts at a load(light) that makes them "not equal length" and IMO, they are not electrically joined in the sense that they stay that way depending on the switch position.
 
al hildenbrand said:
???? Again. Look at the Fig. 5 that you posted. The top "traveler" black wire is the continuous hot. If that hot is extended beyond the end threeway switch to any more load, that load current will travel in parallel conductors when the switches are in the exact position shown in the Fig. 5 photo in this thread.



Are the parallel conductors compliant with the language of 310.10(H)? If the conductors are #12 or #14, they are not compliant. They are prohibited.
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I know I must be having a brain dead moment because I do not see this being any different than a 12/3 feed from a switch box to duplex rec. with the tabs cut, one constant hot rec. and on switched rec. how would that be parallel conductors?
 
david said:
I know I must be having a brain dead moment because I do not see this being any different than a 12/3 feed from a switch box to duplex rec. with the tabs cut, one constant hot rec. and on switched rec. how would that be parallel conductors?
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never mind I see what you are saying now the red and black would be going to the same load in post # 5 if the circuit was extended see I told you I was having a brain dead moment.
 
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Then dual switching could be seen as a parallel. 12-3 leaves the switch box from 2 switches and both pass through each light connecting to every other light.
A e-light/ switched gets a switched and constant hot.

Sent from my LGLS620 using Tapatalk
 
electricalist said:
Then dual switching could be seen as a parallel. 12-3 leaves the switch box from 2 switches and both pass through each light connecting to every other light.
A e-light/ switched gets a switched and constant hot.

Sent from my LGLS620 using Tapatalk
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Those conductors are parallel segments of a larger picture but not parallel with each other from the perspective that they are intended to be carrying current to same node of the circuit - they are not even joined together on both ends of a node and are supplying separate loads. The neutral is common and shares the current of the two separate branches got to be careful here - it is not multiple branch circuits - but don't know what else to call it other then split circuit I guess.
 
The hot is electrically joined to the neutral via the load, but I am permitted to have multiple loads on a single circuit.

The phrase in question is not 'electrically joined', but 'electrically joined at both ends to form a single conductor'.

If you are not building a system that depends on the simultaneous function of both paths through the various wires, then you are not electrically joining them to form a _single_ conductor.

In the case of parallel switch loops, each switch loop is installed so that it can supply the full load and function independently of the other switch loop. Each switch loop is properly protected by the OCPD. If you eliminate one switch loop the other is not put at risk of overload.

If this is not clear from the wording, then I agree: the wording should be changed.

-Jon
 
winnie said:
The phrase in question is not 'electrically joined', but 'electrically joined at both ends to form a single conductor'.
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Where are you getting to form a single conductor?


(H) Conductors in Parallel.
(1) General. Aluminum, copper-clad aluminum, or copper
conductors, for each phase, polarity, neutral, or grounded
circuit shall be permitted to be connected in parallel (electrically
joined at both ends) only in sizes 1/0 AWG and
larger where installed in accordance with 310.1 0(H)(2)
through (H)(6).
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Code Panel 6 deleted "electrically joined at both ends to form a single conductor" during the development of the 2005 NEC because the phrase did not provide clarity and was not necessary:lol:
 
RB1 said:
Code Panel 6 deleted "electrically joined at both ends to form a single conductor" during the development of the 2005 NEC because the phrase did not provide clarity and was not necessary:lol:
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Might not be necessary. Depends on what their intent is, if they want it to apply to all possible parallel situations then it is not necessary, if they only want it to apply when the purpose of parallel conductors is to create a higher ampacity conductor then they need to make that clear somehow.
 
Hello,

On the issue of whether the circuit pictured earlier in the thread violates 310.10(H) "Conductors in Parallel", my answer is no, as follows:

The switch is a device and not a conductor (see definition of device).
Therefore the proposed parallel path consists three different conductors: A to B direct, A to switch, switch to B.
No two of these conductors are "electrically joined at both ends".
There is no violation of 310.10(H).

This leads me to my next question:

RB1 said:
Code Panel 6 deleted "electrically joined at both ends to form a single conductor" during the development of the 2005 NEC because the phrase did not provide clarity and was not necessary:lol:
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Now that that phrase is gone, where does the NEC say that the individual conductors of a parallel installation are exempt from 240.4? With the above language, you could treat the paralleled conductors as a single conductor and protect it accordingly.

Thanks,
Wayne
 
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