# Re-wiring dual 3-way switch circuit: is this legal?



## mikewillnot (Apr 2, 2013)

Rewiring a 1920s house, with two pairs of 3-way switches, two at the foot and two at the top of the main staircase, one set controlling lower-level lights on the ground floor & the landing, and the other pair controlling the light in the upstairs hall. 

In rewiring (all on one circuit) I’ll be adding a convenience receptacle in the upstairs hallway below the switches. I’m thinking about fishing two runs of 14/3 from basement to attic, to the upper switchbox (and then 14/2 down to the receptacle), with conductors configured like this:

First 14/3 Romex: 
black & red – jockey legs for upper light switch circuit
white – neutral

Second 14/3 Romex: 
black & red – jockey legs for lower light switch
white – permanently re-identified black or red, carrying unswitched hot for convenience receptacle in upstairs hallway

QUESTION: Haven’t dug into the code on this yet, but my concern is that for the unswitched upstairs load (the hallway receptacle), for a portion of the circuit the hot is coming up through one piece of romex and the neutral through another. 

In the old days (1920s) they used a carter circuit to accomplish this sort of thing, one of which I’m removing here.


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## Black Dog (Oct 16, 2011)

If you are on the 2014 NEC THEN you should bring a 14/2 to feed the receptacle because you must use and AFCI breaker on the circuit.210.12

If not then what you describe will be fine.


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## aftershockews (Dec 22, 2012)

mikewillnot said:


> Rewiring a 1920s house, with two pairs of 3-way switches, two at the foot and two at the top of the main staircase, one set controlling lower-level lights on the ground floor & the landing, and the other pair controlling the light in the upstairs hall.
> 
> In rewiring (all on one circuit) I’ll be adding a convenience receptacle in the upstairs hallway below the switches. I’m thinking about fishing two runs of 14/3 from basement to attic, to the upper switchbox (and then 14/2 down to the receptacle), with conductors configured like this:
> 
> ...


Since you have to fish anyway, why not just bring a 14/2 feed with your 14/3's?


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## bkmichael65 (Mar 25, 2013)

Black Dog said:


> If you are on the 2014 NEC THEN you should bring a 14/2 to feed the receptacle because you must use and AFCI breaker on the circuit.210.12
> 
> If not then what you describe will be fine.


Running conductors of the same circuit in different conduits is fine? I don't think so


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## aftershockews (Dec 22, 2012)

bkmichael65 said:


> Running conductors of the same circuit in different conduits is fine? I don't think so


Needs to be worded different.


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## bkmichael65 (Mar 25, 2013)

aftershockews said:


> Needs to be worded different.


see 300.3(B) for different wording


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## aftershockews (Dec 22, 2012)

> 300.3 Conductors.
> (A) Single Conductors. Single conductors specified in
> Table 310.13(A) shall only be installed where part of a
> recognized wiring method of Chapter 3.
> ...


I was looking for that.


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## Black Dog (Oct 16, 2011)

bkmichael65 said:


> Running conductors of the same circuit in different conduits is fine? I don't think so


You're right about that, I re-read post one:jester:


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## mikewillnot (Apr 2, 2013)

> 300.3(B) Conductors.


Yeah, that's the answer. THX



> Since you have to fish anyway, why not just bring a 14/2 feed with your 14/3's?


Looks like I will. Rewiring the whole second floor. The only chase I've got so far, along the vent stack, is probably going to be crowded, what with all the power and switching lines. I'm thinking about running PVC up the side of the house and in through an eave.


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## McClary’s Electrical (Feb 21, 2009)

bkmichael65 said:


> Running conductors of the same circuit in different conduits is fine? I don't think so


You're correct, black dog is wrong. You cant run your grounded conductor in a seperate cable assembly from the ungrounded. 
Will it work? Yes, 
It is to code? No


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## Dennis Alwon (May 9, 2009)

I disagree. With nm cable you can run the wires in separate cables. Read further down- too lazy to get up and lopok. There is an exception for non ferrous cables and raceways


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## Dennis Alwon (May 9, 2009)

I think the art. is 300.3 (B)(3)


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## macmikeman (Jan 23, 2007)

Dennis is correct. This is still legal using NM cables. I'm surprised that code proposal junkies haven't closed this loophole, what with some people sending in dozens of proposal all the time just to get their name up in lights on Broadway.


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## McClary’s Electrical (Feb 21, 2009)

Then why would anybody use 14/3 for three ways? Why don't we ask just use 14/2 like shock doc?


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## macmikeman (Jan 23, 2007)

mcclary's electrical said:


> Then why would anybody use 14/3 for three ways? Why don't we ask just use 14/2 like shock doc?


It is a lot easier to use 14-3 for 3 way switching then to feed one end with 14-2, run a 14-2 to the other side for the travellers, and then run another 14-2 to the other side as well so you get the same circuit neutral out to the lights as you have fed the switches with in the first place.


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## Dennis Alwon (May 9, 2009)

macmikeman said:


> Dennis is correct. This is still legal using NM cables. I'm surprised that code proposal junkies haven't closed this loophole, what with some people sending in dozens of proposal all the time just to get their name up in lights on Broadway.


I did make a proposal to do away with this-- I doubt it will get a second look.

The problem I have with this install is that it creates unwanted emf's. I don't want to get into the voodoo about this but many people complain about it and we are not sure of long term affects from it.


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## macmikeman (Jan 23, 2007)

Dennis Alwon said:


> I did make a proposal to do away with this-- I doubt it will get a second look.
> 
> The problem I have with this install is that it creates unwanted emf's. I don't want to get into the voodoo about this but many people complain about it and we are not sure of long term affects from it.


I was jerking your chain, I knew you proposed that......:laughing:

Those people worrying about emf's should throw the Iphones they keep in their pocket into the trash, cause they get a larger dose playing twitter all day than the two wire travelers are dosing them with.


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## 51360 (Jun 9, 2014)

Dennis Alwon said:


> I did make a proposal to do away with this-- I doubt it will get a second look.
> 
> The problem I have with this install is that it creates unwanted emf's. I don't want to get into the voodoo about this but many people complain about it and we are not sure of long term affects from it.


In the CEC there are no exceptions regarding NM and simple 3-way switching.

I agree that emf's are not fully understood. Minimize the risk, run the 14/3, and keep your circuits in one cable. 

Borgi


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## cal1947 (Nov 14, 2009)

*cal1947*



mikewillnot said:


> Yeah, that's the answer. THX
> 
> Looks like I will. Rewiring the whole second floor. The only chase I've got so far, along the vent stack, is probably going to be crowded, what with all the power and switching lines. I'm thinking about running PVC up the side of the house and in through an eave.


cannot run romex in pipe outside , romex cannot be used in damp locations


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## Dayvieboy (Jan 16, 2017)

bkmichael65 said:


> Running conductors of the same circuit in different conduits is fine? I don't think so


Having neutral & Hot in separate conduits creates magnetic fields and possibly a small amount of heat?


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