Using neutral as a traveller on 3way switch

[al hildenbrand]

Re: Using neutral as a traveller on 3way switch

Goldstar,

The first switch in the branch circuit is the breaker.

 

[al hildenbrand]

Re: Using neutral as a traveller on 3way switch

Here's the real question:

Imagine: Occupancy with a single phase circuit breaker service center that is 100 Amp, 120 / 240 Volt. The service center has 15 and 20 Amp branch circuit breakers that include SWD capability. (Think of, say, the standard Square D QO115 and QO120, Siemens Q115 and Q120, Cutler Hammer CH115 and CH120, etc.)

The occupancy branch circuits are wired with NM-B.

Imagine a fluorescent luminaire in the occupancy controlled by one wall mounted single pole switch. . .The branch circuit feed goes to the J-box above the luminaire on a 14-2 NM-B, and another 14-2 NM-b goes from the luminaire J-box to the single pole switch.

Is the black conductor connected to the circuit breaker used as a return conductor from the switch to the switched outlet?

-OR-

Is the black conductor connected to the circuit breaker used for the supply to the switch?

 

[goldstar]

Re: Using neutral as a traveller on 3way switch

Is the black conductor connected to the circuit breaker used as a return conductor from the switch to the switched outlet?

-OR-

Is the black conductor connected to the circuit breaker used for the supply to the switch?

The black wire coming from the breaker is spliced (at the lighting outlet) to the white (re-identified with a piece of black tape) going down to the light switch. At the switch the white (again re-identified) is now the feed to the switch and the black returns to the lighting outlet. That way, at the lighting outlet you'll only have 1 black and 1 white lead to which the light is connected. This should be common knowledge for all of us.

The real issues are whether white wires can be re-identified when used as travelers and as returns from 3-way switches. There are different issues when talking about runs in conduit. In those cases there should be no reason to run white wires to a switch. However, in the case of cable assemblies (such as AC and NMC 3-wire) I haven't seen any of those made without a white wire. So why shouldn't it be permissable to re-identify ?

 

[al hildenbrand]

Re: Using neutral as a traveller on 3way switch

Thanks for the response, Goldstar. I agree that the question in this thread is ultimately "whether white wires can be re-identified when used as travelers".

I suspect that the confusion around the language used in 200.7(c)(2) comes from mental substitutions for the exact words used. Your description of re-identifying the white conductor in the 14-2 switch loop is, perhaps, just such a case.

Answering my own question: The conductor running from the OCPD, the 15 or 20 amp circuit breaker marked "SWD", through the fluorescent luminaire J-box and down to the wall mounted toggle switch is a conductor between two single pole switches.

It is easy to see this conductor is used for the supply to the switch. After all, it's the branch circuit hot conductor. . .right? But the breaker is listed as a switch. From the White Book:

Switching Type--
Circuit breakers marked "SWD" are suitable for switching 120, 277 or 347 volt fluorescent lighting on a regular basis at the rated voltage.

This "SWD" breaker is not a special breaker. Virtually all commodity single pole 15 and 20 amp circuit breakers are listed Type SWD.

So, the conductor beginning at the breaker and ending at the wall mounted toggle switch is between two switches. Looks like a "traveller" to me. A traveller is a conductor connected on either end to a switch.

So, do we make 14-2 and 12-2 NM switch loops a violation of the NEC? No, because the re-identified white wire ends at a switch, thereby supplying the switch that it ends at. The wire that connects to the switch on one end and connects to the luminaire on the other end has to be black because it is

200.7(c)(2)
a return conductor from the switch to the switched outlet.

A traveller is connected to a switch on both ends. No luminaire. A traveller cannot be

200.7(c)(2)
a return conductor from the switch to the switched outlet.

because it doesn't end at the switched outlet.

 

[macmikeman]

Re: Using neutral as a traveller on 3way switch

The way I read the code is that you better be re-identifying the white as an ungrounded conductor on a three wire cable if you are between two three ways. If you are using the re-identified white as a common back up to the light, you are violating. This is not to be used as a return to the light. I am sorry but i have to disagree with Don on this one. You can use either the red or the black as a common on the 3 way return, but not the re-id white .

 

[al hildenbrand]

Re: Using neutral as a traveller on 3way switch

Don,

In your first comment back on page one of this thread

In my opinion, 200.7(C) prohibits the use of the white conductor in a NM cable as a traveler or a feed to the light.

you call the conductor connected to the switched outlet a "feed to the light". If this return conductor from the switch to the switched outlet "feeds" the light, that is, is used for the supply to the light, then why isn't the traveller connected to the downstream threeway a supply to that threeway switch? (Thus, in your opinion of 200.7(C), dis-allowing re-identifying of the white conductor used as a traveller.)

 

[don_resqcapt19]

Re: Using neutral as a traveller on 3way switch

Al,
I just don't see the travelers being the feed to the second 3-way switch. I must be wrong, because in the case of a 3 conductor cable containing the travelers and the switch leg to the fixture, you are required by code to use the white as a traveler, because you can't use it for the switch leg.
Don

 

[ronaldrc]

Re: Using neutral as a traveller on 3way switch

This arguement about this white wire being used as a hot is as fruitful as the 12 and 13 if you know what I mean.

Last time I got into this arguement I ask what choice we had in electrical work if we were using 12/nm for a switch? Do we now have to use a 12/3 and not use the white?

He said they now have a nm romex with either 2 Blacks and a bare or a nm with 1 red and 1 black and a bare forgot which but I still have never found this type nm yet?

Ronald

 

[don_resqcapt19]

Re: Using neutral as a traveller on 3way switch

Ron,
There is no question that you can reidentify the white and use it as the hot to the switch. That is very clear in 200.7. The use of the white for a traveler is not as clear, but I have been convinced that it is permitted.
Don

 

[ronaldrc]

Re: Using neutral as a traveller on 3way switch

Don what you described as a three wire switch leg with two travelers and a return is the same as a single pole as far as use of the white wire if we have a 3 wire three way with two conductors being used as travelers and 1 for the light return. I wouldn't use the red and black as travelers because when you get to the light you would have to hook your light to two whites, so I would definetly use my white as a traveler in this configuration so I can hook my light to a white neutral and a black hot.

Go here to see diagram

Ronald

[ September 22, 2003, 03:33 PM: Message edited by: ronaldrc ]

 

[al hildenbrand]

Re: Using neutral as a traveller on 3way switch

In the case of a 3 conductor cable containing the travelers and the switch leg to the fixture, you are required by code to use the white as a traveler, because you can't use it for the switch leg.

Excellent point. Well said.

 

[ronaldrc]

Re: Using neutral as a traveller on 3way switch

Al eveyones terminology is a little different in the electrical trade, I always pictured the switch leg as the whole switch loop from the connection at the hot feed of the wire that feeds the switch all the way to the hot connection to the light itself.

This is not that big a deal, I just like the idea of having a black and white to hook my light to.

Ronald

 

[don_resqcapt19]

Re: Using neutral as a traveller on 3way switch

Ron,

This is not that big a deal, I just like the idea of having a black and white to hook my light to.

That is a big deal and is the purpose of the code rule permitting the reidentified white to feed the switch, but not permitting the reidentified white to feed the fixture.
Don

 

[ronaldrc]

Re: Using neutral as a traveller on 3way switch

Don I agree it is that big a deal if for some reason certified electricians start hotting the switch with the black and hanging the light on two whites even if one is marked.

Because down the road someone might take the marking tape off or cut it back behind the paint if painted.Then you wouldn't no which white was hot and which was neutral.

But why would we ever do it that way? We are taught different we are always taught in romex wiring with a switch leg to hot the white one and return to the light with the black.

Ronald

 

[al hildenbrand]

Re: Using neutral as a traveller on 3way switch

Ronald,

I always pictured the switch leg as the whole switch loop from the connection at the hot feed of the wire that feeds the switch all the way to the hot connection to the light itself.

I understand your image completely, and this underscores the importance of the specific words of 200.7(c)(2) as the wires talked about are not named "switch leg" or "hot feed".

Rather there is the wire that is used as the return conductor from the switch to the switched outlet and there is the wire that is used for the supply to the switch. (The black italics are the code words verbatim.)

Don,

The engineer side of my brain sees fall of potential from the line side of the supply to the return side. The switch contacts have a real and measurable (though small) contact resistance that causes a drop in potential from line to load side. There is also a material resistance that can be included (though smaller still.) When a switch is inserted into a circuit, the higher potential terminal is the supply.

I admit that this "fall of potential" perspective gets to be a little like a hall of mirrors as one starts breaking down a given length of a single un spliced conductor into imaginary shorter and shorter pieces. . .kind of the differential of change of voltage with respect to the infinitesimal length of a segment of conductor. . .but never mind. My point is that the terminal of a switch that is toward the high potential side of the power supply is the "supply" to the switch because the voltage falls as one goes to the load side of the contacts.

 

[justoys]

Re: Using neutral as a traveller on 3way switch

Hey everyone. I think you are reading into this a little to far. I have a simple mind so this is only my thoughts and opinons. If you re identify a conductor, have you not changed it's color. If you have changed it's color is it not re identified and therefore no longer it's original color? If it's not it's original color in this case it is no longer white, etc... and is therefore allowed to be a current carrying conductor. One step further, if I have a roll of black thhn or something of that nature, and I need it to be a grounded conductor, can I not re identify it with white, etc...? I have been doing this for 18 years and every AHJ seems to be concerned that the NON current carrying conductors are properly identified. Therefore no white, etc.. shall be ungrounded.

I think that came out the way I wanted it to.

[ September 22, 2003, 08:07 PM: Message edited by: justoys ]

 

[goldstar]

Re: Using neutral as a traveller on 3way switch

OK. Although this is an "unofficial interpretation" of 200.7 (C)I did get a response back from Charles Miller and hopefully this will clear up some of this confusion.

My inquiry to Mr. Miller

Dear Mr. Miller :

I wonder if you could help clarify a dilemma. We recently discussed the topic of re-identifying the white wire in a 3 wire (NMC), 3-way/4-way switch scenario in Mike Holt's NEC code forum. There were numerous responses, all of which seemed fairly intelligent and believable depending on how you interpret the code. The discussion began with the question as to whether the white wires can be used as travelers in a 3-way circuit. My response was that they could be used this way as long as they were re-identified for their intended use. In addition I described a scenario where the feed for the 3-way circuit started out in the switch box with the white wire being neutral, the red and black wires being travelers and running to the light outlet. At the light outlet the red and black wires are spliced thru to the load side of the 3-way circuit where the white wire in the 3 wire (NMC) is reidentified at both the lighting outlet and at the switch. Several people responded that it was a code violation to do this citing section 200.7(C)2.

If you could find the time I would appreciate hearing from you on this topic and whether white wires in a 3-wire cable assembly can be used as travelers and also whether the white wire in a 3-way switch scenario can be re-identified if it is a return from a 3-way switch.

Thank you in advance,

Phil Bufis
Gold Star Electric
Ringwood, NJ

Mr. Miller's response

Hi Phil,

The white wire can be installed in a 3-way (or 4-way) switch loop if it is reidentified. Your scenario from the switch box to the light fixture is correct. The white wire is the grounded conductor and the black and red are travelers. Even if the white wire is reidentified, it cannot be the return conductor from the other switch to the light fixture. I know it seems like it would be better to keep the same color coding, but it is a violation. Either the red or black must be the return conductor feeding the light. A reidentified white wire can feed down to a 3-way, but it cannot bring power back to the light fixture. Although this is not the answer you are looking for, I hope it helps.

Charles Miller

Have you seen a copy of my book titled, Illustrated Guide to the National Electrical Code?

In light of this I guess, in my scenario, the proper way to wire this circuit would be to re-identify the white at the lighting outlet and make it a traveler and use either the black or red as a return to the lighting outlet. In addition, if you are using the white as a traveler it must be re-identified at each point.

[ September 22, 2003, 08:17 PM: Message edited by: goldstar ]

 

[Guest]

Re: Using neutral as a traveller on 3way switch

Originally posted by goldstar:
[QB] <big snip>The white wire is the grounded conductor and the black and red are travelers.<big snip>

Did you cut-and-paste this, or did you re-type it? Regardless, the above statement confuses me. I would expect it to say:

The white wire is the [re-identified] [un-]grounded conductor and the black and red are travelers.

[ September 22, 2003, 09:45 PM: Message edited by: awwt ]

 

[don_resqcapt19]

Re: Using neutral as a traveller on 3way switch

justoys,

if I have a roll of black thhn or something of that nature, and I need it to be a grounded conductor, can I not re identify it with white, etc...?

You can only do that if the conductor is #4 or larger. See 200.6(B).
Don

 

[al hildenbrand]

Re: Using neutral as a traveller on 3way switch

Wayne,

Phil said it correctly for the configuration he is describing. The branch circuit supply comes to the first threeway switch bearing the black and white. The black goes to the common on the switch and the white, the neutral, is spliced to the threewire cable white. The red and black are the travelers. This threewire cable leaves the first threeway switch and goes to the J-box above the switched outlet. At the J-box above the luminaire (in Phil's example) the white is connected to the luminaire grounded conductor. The red and black are spliced to the threewire cable that continues on to the second threeway switch.