Using 12-2 for travellers between two 3-way switches

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There is no reason that the white wire from the 2 wire cable cannot be marked black and used as a traveler.
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Or yellow.

The most foolproof way I have found to wire 3-ways is to use a two wire cable as a traveler and re-mark both the black AND the white with yellow tape.

The feed to the first switch and the final switch leg to the light both stay black.

Since the travelers will go on the brass, or yellow terminals and the blacks will go on the commons, this makes for an easy hook up, especially if you have been away from the job for a while waiting on the drywallers.
 
jumper said:
I just checked, the white as a traveler would violate 200.7(C)(2).
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Jumper, you can use the white as a traveler and re-identify it as long as it isn't the return to the light.

Dennis Alwon said:
Let's summarize---This was a common install but usually it was done with the neutrals from the same circuit. It is still legal today if they are on the same circuit and done with nm cable or non ferrous raceways or cables. Now emf's is definitely an issue but for some reason the NEC does not care.

In the op example it is clearly a violation but it would not be a MWBC since there would be no voltage between conductors. There is no reason that the white wire from the 2 wire cable cannot be marked black and used as a traveler. The white conductor can never be re-marked and used as a return to the outlet.
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The OP said to ignore the neutral issue, so I only responded to the 12-2 for travelers. That is not a violation, IMHO, it would be no different than using 12-2 for a 4-way between two 3-ways.
 
K8MHZ said:
Or yellow.

The most foolproof way I have found to wire 3-ways is to use a two wire cable as a traveler and re-mark both the black AND the white with yellow tape.

The feed to the first switch and the final switch leg to the light both stay black.
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This still leaves us with the EMF issue.

Roger
 
Howard Burger said:
Is running three way switch travellers on 12-2 legal?

Ran across this in a resi. troubleshooting call: power came into first three way at bottom of stairs, travelled via 12-2 to second three way at top of stairs.

Then, in the second box was another circuit which provided the neutral back to the panel. Ignoring the potential for overloading the neutral with two same-phase circuits, is running the travelers by themselves a violation? Or does 300.3.B.2 allow it?
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Howard,

Perhaps this is a little more accurate. I pulled the hot and neutral of the single branch circuit feed together and placed them at the light.

The branch circuit hot and the branch circuit neutral could be in opposite 3-way locations. As pointed out, if the hot and neutral come from the same branch circuit, or a legitimate multiwire branch circuit, then there are no NEC issues.

TwoConductorNM3-wayfeedatlight_web.jpg
 
Little Bill said:
How do you wire a 4-way? If you use 12-2 you are just extending the travelers.
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Looking at the diagram that I just posted, just cut in a 4-way switch anywhere along the travelers, as many times as you want.

Each 4-way then has 2-conductor NM in and 2-conductor NM out.
 
jumper said:
I think you may get EMF issues here also, but EMF is not a NEC issue.
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OK, now I see what is going on.

Guys, EMF is voltage.

EMI is electromagnetic interference.

RFI is radio frequency interference.

At least to engineers. We and the sheeple use EMF to mean electromagnetic field, which I think is confusing. EMF for electromotive force is an acronym, EMF to mean electromagnetic field is more like slang.

That being said, WHAT electromagnetic field or interference issues are there with running travelers without a neutral?

Especially when the light is the first connection. You can run all the neutrals you want and NO current from the light will flow through any other neutral in the circuit. All the current (unless there is a fault or a parallel path) will go from the light directly back to the panel.

So, unless the neutral run with the travelers is not ahead of the light, there will be no 'cancelling current'.

My experience with radios (I have a bunch) is that RFI (interference you can hear on a radio) from a 60 Hz electrical system indicates problems.

So, please can someone tell me exactly what the 'EMF issues' are?
 
Here's another picture of a California Threeway setup, as described in the OP.

Cali3way.jpg


If both threeways get their neutral from the same circuit, it's legal (with NM and nonmetallic boxes.) I think it would be legal if existing prior to the 2005 NEC on different circuits of different phases.
 
K8MHZ said:
I am not sure what you are talking about.

What EMF issue? EMF = electromotive force which is another way of saying voltage.
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It also means Electromagnetic Field(s) which is suspect in childhood Leukemia as well as causing EMI

You can choose to worry or not worry about either but they are both problems that could be caused by your wiring method.

Roger
 
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roger said:
It also means Electromagnetic Field(s) which is suspect in childhood Leukemia as well as causing EMI

You can choose to worry or not worry about either but they are both problems that could be caused by your wiring method.

Roger
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How?

How many mG do you think my no neutral traveler would be detectable outside the wall it is in?

(I am not buying the disease issue, I saw how the tests were done and the ambiguity thereof, however.......)

Let's say it was 4, which is pretty substantial (and not likely).

Here is what it is in a sea of:

Personal hair trimmer (1 AA battery): cutting tip, contact 10-20mG; shaft/handle, contact >70mG. Electric hair clipper: cutting head, contact >70mG; handle, contact >70mG. Hair dryer, 1200 watts: low & high, 6 inches from nozzle 5-10mG; handle, contact >70mG.

Electric toothbrush: brush tip, contact <2mG; brush shaft middle, contact 4-5mG; handle, contact 40-50mG.

Refrigerator: front, 1 foot 3-5mG.

Microwave oven: front, running, 1 foot 40-50 mG; front, unplugged, 1 foot 4-5 mG.

Electronic dictionary (2 AA batteries): contact <2 mG.

Desktop computer: LCD monitor, 1 foot <2mG; 2 feet <2 mG. CRT monitor, 1 foot 2-5 mG; 2 feet <2mG. CPU fan, 6 inches 4-5 mG. Right speaker, power off, 1 foot 2-3 mG; power on, 1 foot 4-5 mG. Computer mouse, contact <2 mG.

Laptop computer: LCD, 6 inches <2mG. Keyboard and bottom of laptop, generally <2mG, But over area of CPU/fan, >70mG when CPU is busy and/or cooling fan is running (also >70mG from the bottom, which contacts your "lap", so be careful where on your lap you have it, and for how long).

Electric clock radio: 6 inches, <2mG; but AC/DC adaptor, 6 inches 30-40mG, 1 foot 2-3mG.

Personal "sex toy" vibrators: Mini vibrator (one battery about two-thirds the size of one AA battery), contact 10-20 mG. Standard-sized vibrator (3 AA batteries in the separate control case, attached by a wire), contact >70mG with rotation function, >70mG with vibrator function. (Disclaimer: These items are, of course, not mine! I merely borrowed them, for testing, out of intellectual curiosity...)

Electric carpet: contact >70mG. Electric foot warmer: contact >70mG. Electric blanket, "99.98% EMF Cut": contact <2mG, but the wire from the control to the blanket and the plug into the blanket, contact >70mG. (My old electric blanket, now long gone, gave a reading similar to the electric carpet, >70mG on contact.)

Wristwatch (button battery): contact <2mG.

Gas fan space heater: plugged in but turned off, 1 foot 3-4mG; turned on, 1 foot 4-5mG. Air cleaner: turned on low, 1 foot 3-4mG; medium, 1 foot 4-5mG; high, 1 foot 5-7mG.

Remote controls: for TV, DVD/video, air cleaner: all, contact <2mG.

Fluorescent tube round, 20-watt: 1 inch 40-50mG; 6 inches 2-3mG (just at the top of my head). Fluorescent tube straight, 20-watt: 6 inches 3-4mG, 1 foot <2mG. Fluorescent bulb: company A, 20-watt, 6 inches <2mG; company B, 12-watt, 6 inches 3-4mG, 1 foot <2mG.

Outlet, wall or at the end of an extension cord: not being used <2mG; but with something plugged in and running, 6 inches 3-4mG, contact >70mG. Any wire with current running through it: contact >70mG.

TV, 21 inch, CRT: 2 feet 4-5mG. DVD/video deck: 1 foot 3-4mG, 2 feet <2mG.

Washing machine: running, from the front, 1 foot 4-5mG.

Rice cooker: 1 foot 4-5mG.

Sunlamp, 800 watt: 6 inches 5mG, 12 inches 3mG, 18 inches 2mG. (This is a full-spectrum Sperti sunlamp.) The company recommends you use the sunlamp no closer than 18 inches.

Electric power lines about 10 feet away from my balcony here on the second floor: 3-4mG on the balcony; extending to 3mG 1 foot inside the bedroom adjacent to the balcony.

Hamster warm house floor: low heat side, contact 3.0-3.5mG; high heat side, contact 3.5-4.0mG. (I tried several layers of aluminum foil, but that did not reduce the level at all. Then I read that only iron can block EMFs, so I went to the home center and found a wok made partially of iron. I took it over to the fluorescent bulb section, found a bulb emitting strong ELFs, then held the wok between the bulb and my Gauss meter probe. The wok reduced the reading to almost background levels. So I've got until winter to find a small iron plate to protect my hamsters from EMFs.)

Cell phones: This is not related to RF emission, which is a separate problem. I've tested about 12 cell phones from several different companies, and each one emits ELFs from different points of the cell phone even when you are not talking on it or using it in any way. Company A, with the batteries removed, contact 3?50mG, strongest near the antenna. Company A's battery: 2-3mG. Company B, with the battery installed and the phone turned on but not using it, contact 3 to >70mG, strongest near the internal antenna. (I have stopped carrying my cell phone in my pocket or anywhere in contact with my body. It may be just coincidence, but on my right side, just where my right side pants pocket is, and where I carried a cell phone for 5 years or more, I've got a small lump. It's probably just a subdermal lipoma, not malignant, and as I said it might be merely coincidence, but I believe it's better to be "safe than sorry".)

Learn more: http://www.naturalnews.com/023307_EMF_reading_cell_phone.html#ixzz1WLNwN8DA
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K8MHZ said:
How?

How many mG do you think my no neutral traveler would be detectable outside the wall it is in?

(I am not buying the disease issue, I saw how the tests were done and the ambiguity thereof, however.......)

Let's say it was 4, which is pretty substantial (and not likely).

Here is what it is in a sea of:
Click to expand...

I have seen your list a number of times, here on the forums a few years ago for one.

It doesn't matter what the level is, what I think, what you think, what your buying, or what your not buying, as of now the NEC allows it in NM wiring methods. I just simply told you what EMF stands for and much to your dismay, it is a little more than trade slang used by lower level laymen. It does in fact stand for "Electromagnetic Field" and is used by Engineers, Scientist, Doctors, Professors, Researchers and so on, click the link below to see how widespread this incorrect term is used through out many levels, it may just be something new to you that you have never heard before.

http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4ACGW_enUS396US396&q=EMF+Leukemia

As I said, until the NEC changes the rule it is your prerogative to worry or not worry about the issues caused by your wiring method.

Roger
 
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Dennis Alwon said:
I always run 3 wires between the 4 ways-- pass the neutral thru.
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Neutral or a return wire if there is just a switch at the end and no load. The idea is when there is a load you should be able to clamp a ammeter on the cable and read zero.

300.3(B) requires all conductors of a circuit to be in same raceway or cable for a few reasons. One reason is if all conductors are in close proximity to each other is so magnetic fields will cancel each other. This will also help lower impedance of the circuit - especially during short circuit conditions and allow faster operation of overcurrent devices.
 
roger said:
I have seen your list a number of times, here on the forums a few years ago for one.

It doesn't matter what the level is, what I think, what you think, what your buying, or what your not buying, as of now the NEC allows it in NM wiring methods. I just simply told you what EMF stands for and much to your dismay, it is a little more than trade slang used by lower level laymen. It does in fact stand for "Electromagnetic Field" and is used by Engineers, Scientist, Doctors, Professors, Researchers and so on, click the link below to see how widespread this incorrect term is used through out many levels, it may just be something new to you that you have never heard before.

http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4ACGW_enUS396US396&q=EMF+Leukemia

As I said, until the NEC changes the rule it is your prerogative to worry or not worry about the issues caused by your wiring method.

Roger
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Then this is bad, too, then?

View attachment 5714

Even though I find the studies done to be suspect, I am still interested in this, nonetheless.

How is running a two wire traveler any different than only running the hot and the switch leg to the switch? Neither have a neutral to cancel them out.
 
K8MHZ said:
Then this is bad, too, then?

View attachment 5714

Even though I find the studies done to be suspect, I am still interested in this, nonetheless.

How is running a two wire traveler any different than only running the hot and the switch leg to the switch? Neither have a neutral to cancel them out.
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in the switch loop current on one conductor is flowing the opposite direction of the other and equal amount thus they cancel. Same with three wire cable to a end of line three way switch. two conductors are carrying current when the load is energized, current is in opposite direction on each conductor and equal amount.

Add: with the two wire traveler you have current flowing only on one conductor at a time and no other carrying equal and opposite current within the cable or raceway.
 
The electrons are traveling in opposite directions. It does not take a load to get this. Slap an ampclamp on a receptacle and a pair of wires of a dead-end switch and you'll get the same reading: 0.
 
It is very different. Basically a switch, as drawn above, is the same as if one wire is longer than the other. Think of the white wire in the box 8" long and the hot wire 48" long. There would be no EMF's to worry about the neutral will cancel the emf when they get together.
 
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