3 way switch wiring

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qcroanoke

qcroanoke

Sometimes I don't know if I'm the boxer or the bag
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Sorta retired........
ok, I know how to wire a 3 way that's not the question.
This is: If I have a feed and neutral (same circuit) at both locations will I be compliant by
pulling a 14-2 w/g bettween them to use for travellers?
 
qcroanoke said:
ok, I know how to wire a 3 way that's not the question.
This is: If I have a feed and neutral (same circuit) at both locations will I be compliant by
pulling a 14-2 w/g bettween them to use for travellers?
Click to expand...
Paying attention to 300.3(B)(3), yes.
 
Ah 14-3/g, via 2 travelers and a neutral... existing @ 2 (hots) and you have to carry the neutral forward, 1 hot will be a slave hot...

It's the weekend call me a box of rocks ...

It looks good on my sketch :)
 
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roger said:
I agree, this equates to EMF issues.

Roger
Click to expand...

How so? If I have 2 travelers and 1 equipment ground in the romex wouldn't the ground work as a return
(is that the right word?) to cancel out the EMF? I have no problem using 14/3 just didn't want to if I don't need to. The ground would be connected to the neutral bar in the panel because that is where the neutral/ground bond will be made.
 
qcroanoke said:
How so? If I have 2 travelers and 1 equipment ground in the romex wouldn't the ground work as a return
(is that the right word?) to cancel out the EMF? I have no problem using 14/3 just didn't want to if I don't need to. The ground would be connected to the neutral bar in the panel because that is where the neutral/ground bond will be made.
Click to expand...

No, the equipment EGC carries no current and will do nothing to cancel EMF.

Draw your circuit out with arrows showing current flowing from your hot supply conductor and returning on the neutral, you will see that you will only have current flowing in one direction in the traveler portion of your circuit so there is nothing cancelling the EMF.

Roger
 
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My guess would be that you need a CCC in opposition to and of equal magnitude to cancel the field.
So the ground won't work in that sense. That's my guess, I'll leave technical stuff for someone else.
 
qcroanoke said:
How so? If I have 2 travelers and 1 equipment ground in the romex wouldn't the ground work as a return
(is that the right word?) to cancel out the EMF? I have no problem using 14/3 just didn't want to if I don't need to. The ground would be connected to the neutral bar in the panel because that is where the neutral/ground bond will be made.
Click to expand...
You stated that a hot & neutral are at each threeway and only the travelers go between the switches.

For that setup to turn a light on and off, the common of one threeway will be connected to a hot and the neutral will not connect to anything. Current from that hot goes through that threeway and down a traveler to the other (second) threeway where the common is connected to a switched leg going to the light (presumably in another 14/2). The neutral from the light connects to the neutral at this second threeway (note that the hot is not connected to anything). The current returns to the source along the neutral at the second switch.

In this setup, the only time the current, going in one direction in a cable is beside the same current returning inside the same cable, is in the switched leg between the second threeway and light.

Otherwise, the current is unbalanced and creating an un-canceled magnetic field.
 
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