Is One of These Wires Neutral (3-way switch)

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  #1  
Old 05-01-14, 01:34 PM
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Is One of These Wires Neutral (3-way switch)

I'm in Washington, DC. I would like to install a Legrand Adorne SofTap universal dimmer to replace a regular switch. This is the dimmer:

adorne® sofTap Dimmer, 700W (Incandescent, Halogen, CFL, LED, ELV, MLV, Fluorescent) | by Legrand

This dimmer requires a neutral wire. I’m trying to find out if there is a neutral wire at the second of two switch locations that control three recessed cans.

At the first switch location, I successfully installed an Adorne paddle switch. There are two 14-2 cables and one 14-3 cable. Allow me to refer to the three cables as A, B and C (14-3). Here's a picture:

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The three ground wires are connected together and to the ground from the switch.

The black wire from cable A is connected to the black wire from cable C.
The black wire from cable B is connected to the HOT on the switch.

The white wire from cable A is connected to the white wire from cable B.
The white wire from cable C is connected to the 1-Pole on the switch.

The red wire from cable C is connected to the 3-Way on the switch.

That all seems to work fine.

At the second location, where I want to place the dimmer, there currently is a regular switch and only the 14-3 cable (cable C) enters the box. The ground is attached to the switch ground. The black is attached to the Common. The white is attached to one of the two available screws. The red is attached to the other available screw. (All the screws on this switch are the same color.)

Using a DMM at the second location, I found:

Black – Ground reads 120V
Black – White reads 98V
Black – Red reads 120V
Red – Ground reads 0V
Red – White reads 9.6V
White – Ground reads 9.6V

Placing the red lead only on the black wire and the black lead on nothing gives a reading of 8.7V

Using an NCV detector, I found:

It buzzes strongly at the black wire.

It buzzes slightly at the white wire.

It doesn’t buzz at all on the red or ground wires.

Is one of the wires at the second switch location considered the neutral wire? If so, are the DMM readings normal? If I don’t have a neutral wire, I guess I can use a dimmer that doesn’t need a neutral but those won’t be universal. Or is it possible to place the dimmer at the first location? (Sorry, I didn’t take readings there.)

Thanks so much for your help.
 
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  #2  
Old 05-01-14, 03:01 PM
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A neutral wire is never connected to a three way switch. You will see a "white" wire connected (traveler) but it is not used as a neutral. The "white" wire in a 3 way set up can carry current depending on what screw it is connected to. 3 way switches require one common (either from power or to light only) and one each to each traveler screw. Common screws are normally brass and travelers are silver. If a "white" wire goes to a 3 way switch it should be marked with black tape showing it may carry current. If one end only has three wires in the same cable that indicates that this common is connected to the light. Therefore the other 3 way switch the power should go to the common screw. On the end where only three wires are there is no need for a neutral and that "white" wire is a traveler. The actual neutral wires on the other side originate from the incoming power and gets connected to the light neutral.
 
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Old 05-01-14, 04:50 PM
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The two whites connected only to each other are your neutral in the box pictured.
 
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Old 05-02-14, 10:49 AM
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Thank you so much to both of you.
 
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