Adding to 3 way circuit

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  #1  
Old 07-02-06, 07:01 AM
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Adding to 3 way circuit

Before I start tearing up drywall today...

I have 4 lights on 3-way switches. The 2 3-way swithes are wired at the end of the run

Breaker -> 4 lights -> switch 1 -> switch 2

Switch 2 has 2 travelers and a neutral (red, black, white).

Can I add a fixture to switch 2? It needs to go right above the switch.

I understand that switch-2 needs the 2 travelers and a neutral.

Can rewire switch-1 somehow to make switch-1 the end of the run so that I can a add a fixture above switch 2?

Thanks,

Aaron
 
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  #2  
Old 07-02-06, 07:15 AM
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No you can not add a fixture to SW2. There is no neutral present in that box even though you have a white wire.

You must add new fixtures starting at one of the existing fixtures.
 
  #3  
Old 07-02-06, 07:44 AM
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as joed told you, you have no neutral at the second switch. You assumption that the white wire was a neutral is incorrect. In fact, you have no neutral at either switch.

You could rewire, but it would require replacing the wires from the last light to the first switch and the between the switches.

Your best solution is to tap one of the existing lights, connecting to the hot and neutral wires attached to the light, and of course connecting the ground wire.
 
  #4  
Old 07-02-06, 08:33 AM
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What if I re-wire switch-1 so it takes on the role of switch-2 and vise versa?

The "wht-coded for hot" would by-pass the first switch box and go to the common of the switch-1 instead of switch-2.

The "blk-neutral" would go to common of switch-2 instead of switch 1.

I can put the light in series with the "blk-neutral" before switch-2.

The travelers would remain unchanged.

Go from this: http://www.handymanwire.com/articles/3waya.gif

to this: http://www.handymanwire.com/articles/3wayc.jpg

I could be missing something...

Thanks again

Aaron
 
  #5  
Old 07-02-06, 08:45 AM
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just hit me that I can't go in series with the new fixture, it needs to be in parralel with the other lights.

I think I understand now. As long as I only have 3 wires going to switch 2, I am going to be out of luck.

I am just dreading repairing textured drywall...

Thanks for your time and quick responses.

Aaron
 
  #6  
Old 07-02-06, 10:00 AM
ddr
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Aaron,

Based on your second to last post where you reference a “blk-neutral,” I’m concerned you still don't understand what joed and racraft were saying: there are no neutrals connected to either switch.

A white wire may be used as a hot conductor provided it is properly recoded at both ends to indicate it is being used as such; it is therefore no longer a neutral conductor but rather a hot conductor. This is common in three way switch setups.

A black (or any other “hot colored”) wire may never be used as a neutral or recoded as such.

Neutral wires serve one purpose: they act as the return path of a circuit. Even if neutral wires pass through a switch box, they are connected to each other to form a continuous path; they are never physically connected to a switch or in any way used as part of the switched path of the circuit.

Please make sure you understand this before doing any wiring and post back if you are not sure about something.
 

Last edited by ddr; 07-02-06 at 03:14 PM.
  #7  
Old 07-02-06, 10:48 AM
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ddr,

I am terrible with terminolgy. Your explination of the term "neutral" helps me quite a bit. I am very familiar with DC circuits and tend to think of things directionally in terms of flow. AC and home wiring are not my forte.

I was really just giving it a name, "black-neutral", because the other conductor (white) in the cable going from the light to SW1 is coded for hot (wrapped in black tape at both ends). I used the term "neutral" because I looked at it as completing the circuit back to the breaker from the switches and the conductor is "white-Neutral" after the light...

So white going to the light is neutral because it goes back to the breaker, but after the light (when it becomes black), it should not be called neutral.

Believe it or not, I was the one who wired these lights and switches, as well as everything else for my finished basement. Electrical theory make sense to me, but I had a heck of a time communicating with my electrical inpector.

One last question:

Can I tap a neutral wire (white, going directly to the breaker) from the 3-gang switch box in which SW1 is located and tie this to the new fixture along with the back wire feeding the common on SW1 (what I called black-neutral) to put the new fixture in parallel with the other lights?

Thanks again.

Aaron
 
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Old 07-02-06, 10:56 AM
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There is the problem. DC wiring often uses black as the negative. Some people think of the neutral as a negative which is entirely wrong.

Not considering grounds here.

There should be 3 wires to each of the three way switches. None of them are neutrals. there are 4 wires to each of the 4 way switches. None of them are neutrals.

this is a rudimentary drawing of a three way set up. a 4 way simpy is tossed in between the two 3 ways with the travelers from each direction landing on the terms of the 4 way.

http://www.hometips.com/hyhw/electrical/22_3way.html

Additional lights would simply be paralleled in (white to white and black to black that is connected to the actual light)
 
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Old 07-02-06, 12:44 PM
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Originally Posted by aaron j
ddr,
One last question:

Can I tap a neutral wire (white, going directly to the breaker) from the 3-gang switch box in which SW1 is located and tie this to the new fixture along with the back wire feeding the common on SW1 (what I called black-neutral) to put the new fixture in parallel with the other lights?
No.

You always want the current in each direction in a cable or raceway to be the same. If you tapped a neutral that was available you would creata an imbalance on both cables (the one from which you grabbed the neutral and the one from which the switched hot wire is from.

This current imbalance would be even worse if two separate circuits are involved.
 
  #10  
Old 07-02-06, 03:22 PM
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Aaron,

Racraft’s electrical knowledge greatly outweighs mine so listen to his answer about tapping a neutral.

I’m curious as to why you seem reluctant to take his advice and simply tap one of the existing lights to run the new light? Is it just the proximity to the switch that makes you want to tap it rather than one of the lights? I don’t know which way the joists run in the area you are dealing with or the placement of the lights, but you may be able to fish the line more easily than you think.

Also, you really need to be careful with your terminology. In your post you were talking about “a neutral wire (white, going directly to the breaker).” Obviously you meant the service panel, breaker panel, breaker box, etc. but NOT the breaker itself.

You said that electrical theory makes sense to you, but I think it would be to your advantage to read (or reread) a book on basic wiring to help you match the theory with some basic terms and wiring layouts. It will also allow you to communicate with others more accurately.

P.S. I edited my above post regarding joined neutrals to more accurately state they form a continuous “path.”
 
  #11  
Old 07-02-06, 03:55 PM
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Everyone, thanks. I tapped a light.

ddr,

The problem was the amount of work required to get to a light fixture. SW2 was easily accessible. Tapping SW1 and running new wires would require drywall holes and going through a floor joist.

Getting to the lights was a lot more work than either switch, although not as much as I thought - dropped a recessed light, a hole in the basement ceiling, fished through floor joist, a second hole in the ceiling, a hole in a sill plate (which was sitting on joists) and a couple of holes in the pantry wall.

I will have a lot of textured drywall blending to do, but I have more light on the stairs now.

True, the white conductor goes to the breaker box not the breaker, but you knew what I meant.

Aaron
 
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Old 07-02-06, 09:34 PM
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Look at it this way... If it were easy everyone would do it.

Anything worth doing is worth doing right!

(sorry thats my dad comming thru).
 
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