White wires as travelers on 3-way

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Re: White wires as travelers on 3-way

Shoot,

Just when it gets interesting, I've got to run about for a bit.

Quickly, then you'all seem to imply that 200.7(C)(2) is a manufacturing standard, not an installation standard.

90.2 comes to mind.

There is a difference between a subassembly, such as the cable, and the assembly of the cable. The full definition for assembly from the IEEE Dictionary goes into it. I'll transcribe it when I get back. . .or maybe someone else will in my stead.
 
Re: White wires as travelers on 3-way

Ok. Here's the definition:

assembly (2) (electric and electronics parts and equipments). A number of basic parts or subassemblies, or any combination thereof, joined together to perform a specific function. The application, size, and construction of an item may be factors in determining whether an item is regarded as a unit, an assembly, a subassembly, or a basic part. A small electric motor might be considered as a part if it is not normally subject to disassembly. The distinction between an assembly and a subassembly is not always exact: an assembly in one instance may be a subassembly in another where it forms a portion of an assembly. Typical examples are: electric generator, audio-frequency amplifier, power supply.
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Re: White wires as travelers on 3-way

Iwire posted February 11, 2005 07:59 AM

By your definition we can call the entire premise wiring system an cable assembly
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If the entire wiring method is cable, yes.
 
Re: White wires as travelers on 3-way

Al it is my understanding that we can only go outside the NEC for definitions when the NEC has not provided a definition.

IMO the NEC has provided a definition for cable assemblies in each of the cable articles.

Originally posted by al hildenbrand:
Iwire posted February 11, 2005 07:59 AM

By your definition we can call the entire premise wiring system an cable assembly
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If the entire wiring method is cable, yes.
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A definition like that is not much help, we might as well call the entire system 'stuff'. :confused:
 
Re: White wires as travelers on 3-way

Iwire posted: A definition like that is not much help, we might as well call the entire system 'stuff'.
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Given that the Search tool for my electronic NECHandbook says there are 324 uses of "assembly" in the Handbook, then yes, it is not much help in describing the list of objects included in a cable assembly.

The definitions of the cables you cite, Bob, modify "assembly" with "factory", or its equivalent, not cable. I don't see "cable assembly" in those definitions.

Some of the parts of a cable, a factory assembly, themselves are assemblies. Consider the insulated conductor which is assembled from copper and plastic.

Look, IMO, "cable" is an adjective modifying assembly, as used in 200.7(C)(2). A cable assembly is a subset of all assemblies, and, as wiring methods go, is distinctly not a raceway assembly. In this manner, the definition of cable assembly is exactly descriptive.
 
Re: White wires as travelers on 3-way

And as for the use of "supply" in 200.7(C)(2), stating that the supply conductor has to be hot all the time to be the supply conductor, and that a conductor between switches can't be hot all the time begs the issue.

The use of switch loops in a dwelling will mostly be on 15 & 20 Amp 120 Volt branch circuits. The commodity single pole 15 & 20 Amp circuit breaker is a switch. The SWD classification as described in the UL White Book means the breaker is a single pole switch. That means, if we follow the thinking of johndeereman's inspector in the post of February 08, 2005 09:04 PM even the branch circuit homerun is not "hot constantly".

And yet, the ungrounded conductor running from the single pole switch circuit breaker to the line side of the switch that controls a switched outlet is clearly the "supply" for the switch. The only difference between the ungrounded branch circuit conductor and the traveller that is hot, is that there is a second conductor available, depending upon 3 & 4 way settings, to carry the load current. That is, the traveller that is hot supplies the next switch. . .just like the branch circuit hot supplies the next switch after the circuit breaker switch.
 
Re: White wires as travelers on 3-way

Resting your case on the toothpick of the term "assembly" is a little odd. The term "factory assembly" is important in 334, because it prevents us from making "Nonmetallic-Sheathed Cable" out of THHN and a roll of black tape. Unless I'm doing it in a factory, it's not a factory assembly.

The use of the term "cable assembly", IMO, is solely to make it clear that this method of switching is only permissible when using cable assemblies, versus raceways. Doing it in raceways would be kinda weird, right? :)

And yet, the ungrounded conductor running from the single pole switch circuit breaker to the line side of the switch that controls a switched outlet is clearly the "supply" for the switch.
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200.7(C)(2) doesn't concern that either, unless for some reason you used the white wire as the hot from your breaker, what're you using as a neutral? Where are you going with this, and will beverages be available when we get there? :D
What are you getting at, Al? How on earth can every supply for every switch in a farmer system be fed with white wires??? If that's not your angle, what is? :D
 
Re: White wires as travelers on 3-way

George,

Let me try another tack.

Prior to adoption of the 1999 Code, the 1996 NEC 200-7 Exception 2 described the use of an un-re-identified white conductor in switch loops.

In my experience, the white conductor of a cable, when used as a traveller, prior to the 1999 NEC was hardly, if ever, re-identified. Yet 1996 NEC 200-7 Exception 1 was the same (with editorial changes) as 2002 200.7(C)(1) which you cite earlier in this thread as being the reason to re-identify the traveller.

The switch loop of a 3 way and/or 4 way was understood as a loop of conductors all the way out, around and back.
 
Re: White wires as travelers on 3-way

I used to make the trim guys scratch their heads when they found my homes with 2 wire travelers (another issue)EMF :D
 
Re: White wires as travelers on 3-way

Originally posted by al hildenbrand:
In my experience, the white conductor of a cable, when used as a traveller, prior to the 1999 NEC was hardly, if ever, re-identified. Yet 1996 NEC 200-7 Exception 1 was the same (with editorial changes) as 2002 200.7(C)(1) which you cite earlier in this thread as being the reason to re-identify the traveller.
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Oh, sure, use my time in the field against me. :)

[ February 12, 2005, 09:41 AM: Message edited by: georgestolz ]
 
Re: White wires as travelers on 3-way

Originally posted by al hildenbrand:
The NEC Handbook has the following text immediately following 200.7(C)(2)
Previous editions of the Code permitted switch loops that contained a white insulated conductor that was used to supply the switch and that was not used to supply the luminaires to remain white. Prior to the 1999 NEC, re-identification of this particular ungrounded conductor was not required. However, many electronic automation devices requiring a grounded conductor are now available for installation into switch outlets. Therefore, re-identification of all ungrounded conductors that are white or any permitted white coloring is now required at each and every termination point. The required re-identification must be effective, permanent, and suitable for the environment, in order to clearly identify the insulated conductor as an ungrounded conductor. Proper re-identification should eliminate the possibility of miswiring new electronic automation devices during installation.
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If this is cause for concern, then perhaps they should modify (C)(2) to add that the common for what I would call a dead-end threeway (switched and fed from the same side) should always be black. If there is a fourway in the middle, that would look like a regular four-way with a neutral tied through. :D

I don't have any earlier than 2002, if I read you correctly, the text that is now (C)(1) is unchanged? This would have required reidentification the whole time...? :confused:
 
Re: White wires as travelers on 3-way

A traveller is definutely not a grounded conductor, it's an ungrounded one. The white wire is being used as an ungrounded conductor, so it must be reidentified. This code does the job. :)
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I totally agree that (C)(1) works. IMO, (C)(2), at best, is redundant, and at worst is a source of enough confusion as to lead johndeereman's inspector to cite it as prohibiting re-identified 14/2 NMB whites as travellers.

Also, IMO, now that (C)(2) is no longer being seen as the reversal of 1996 200-7 Ex. 2, I say it is time to remove it. I think I'll submit a proposal to that effect.
 
Re: White wires as travelers on 3-way

the text that is now (C)(1) is unchanged? This would have required reidentification the whole time...?
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1996 NEC
200-7. Use of White or Natural Gray Color. A continuous white or natural gray covering on a conductor or a termination marking of white or natural gray color shall be used only for the grounded conductor.
Exception No. 1: An insulated conductor with a white or natural gray finish shall be permitted as an ungrounded conductor where permanently re-identified to indicate its use, by painting or other effective means at its termination, and at each location where the conductor is visible and accessible.
Exception No. 2: A cable containing an insulated conductor with a white or natural gray outer finish shall be permitted for single-pole, 3-way, or 4-way switch loops where the white or natural gray conductor is used for the supply to the switch, but not as a return conductor from the switch to the switched outlet. In these applications, re-identification of the white or natural gray conductor shall not be required.
Ex 3: . . .cords. . .
Ex 4: . . .< 50 Volts
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Edit to bold Ex. 1 - Al

[ February 12, 2005, 10:27 AM: Message edited by: al hildenbrand ]
 
Re: White wires as travelers on 3-way

This was included with the IAEI Analysis of the 1999 NEC:
1996NEC200-7IAEIAnalysisImagelores.jpg

George, note the slight variation of the use of the white conductor in the 14/3 (assuming it's #14) carrying the "supply" all the way to the far 3 way of the "farmers 3 way".
 
Re: White wires as travelers on 3-way

Bob,

Note the IAEI use of the term "cable assembly" as used in the above IAEI image.
 
Re: White wires as travelers on 3-way

Oh, and George, thanks for the reference to Photo Bucket .com. I just went through a painless setup. I'm goning to try them out for a while. :cool:
 
Re: White wires as travelers on 3-way

Originally posted by al hildenbrand:
Bob,

Note the IAEI use of the term "cable assembly" as used in the above IAEI image.
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Yes, they are referring to a length of NN (or other) cable. :D

That picture proves either of our points. :D
 
Re: White wires as travelers on 3-way

Hey, Bob.
In this case the NEC has has defined the NM as simply an assembly.
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You forgot the adjective that the NEC modifies assembly with: factory.

Since 200.7 is an installation standard, the components used in the assembly of the installation governed by the standard will be subassemblies if any of them are assembled from other units, parts, assemblies or subassemblies.

Word gamey enough? :D
 
Re: White wires as travelers on 3-way

Originally posted by al hildenbrand:
Hey, Bob.
In this case the NEC has has defined the NM as simply an assembly.
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You forgot the adjective that the NEC modifies assembly with: factory.
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I left it out as it makes no difference, it still is not a factory subassembly.

Starting to wish I did not flunk English each and every year of School. :D
 
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