3 way wiring - neutral required at switches?

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Old 01-28-14, 10:19 AM
J
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3 way wiring - neutral required at switches?

Someone had mentioned that code requires a neutral at each switch in a 3-way light circuit. Does this mean you ALWAYS have to wire through both switches first and then to the lights? Can you ever wire switch > light > switch with 3-way wire? (see diagram below)
 
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Old 01-28-14, 10:36 AM
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You can use 4-conductor cable (white, black, red, blue) from the light to each switch. Conduit does not require a neutral if it can be added when needed.
 
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Old 01-28-14, 11:25 AM
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Ok, so you are confirming I cannot use 3-way wire if I want to wire it from switch > light > switch. I'll need to use 4-way wire. I'm not quite sure what you mean by the conduit comment.
 
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Old 01-28-14, 11:29 AM
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Not to steal Ray's thunder, but if you run Romex, whether it be 2 or 3 or 4 wire, you have one shot. With conduit you can usually add wires at will, if the conduit fill will allow, so adding a neutral can be done later if it is not needed, now.
 
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Old 01-28-14, 11:37 AM
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Ok, thanks. Makes sense. In the case I'm proposing which is a simple three way switch with one light it looks like it DOES require a neutral at both switches. That was the main question. In other words, I CANNOT do what the diagram in my original post suggests (which doesn't appear to have a neutral at the second switch).
 
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Old 01-28-14, 03:31 PM
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If you are on a code older then 2011 you do not need the neutral to meet code. Best practice with more and more switches having auxiliary functions that require a neutral is to future proof with a neutral even if not needed now.

Of course all code is local so always check with your AHJ.

Terminology: No such thing as 3-way cable. There is 3-conductor cable which is often used in 3-way circuits but it has other uses not related to three way switch circuits.

Correction: In my previous post I wrote, "each switch need 4-conducor". Only the right switch need four conductor
 
 

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