Quick circuit question

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  #1  
Old 05-12-13, 07:20 AM
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Quick circuit question

Hello,
I'm trying to install a switch circuit while saving as much wire as possible. To do this, I'm crossing a few wires here -- will this work fine?
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Or will it...
 
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  #2  
Old 05-12-13, 08:08 AM
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Welcome to the forums.

I'm a little confused. You redrew the picture but the wiring is still the same.

You're working with two wire cable with a ground (as a minimum) so you can't really change much in the wiring.

You are showing bringing the hot wire to one fixture first and the neutral wire to the other fixture first ......how would you accomplish that ?
 
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Old 05-12-13, 08:19 AM
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If it seems the same to you , then it'll probably work.
I was just checking.
As for how this would work, I'm putting in a 4 way switch with 2 3 ways over a 25 foot distance. By trying to save the amount of romex used, that's how I get to the second picture. (The switches would all go on the bottom wire of the second pic)
Thank you!
Edit: now I see how my picture seems odd -- there seems to be no difference.
Say we name the left bulb 1 and the right bulb 2.
In the normal wiring, hot 1 and neutral 1 go to bulb 1; hot 2 and neutral 2 go to bulb 2.
In my changed circuit, I'd have neutral 1 and hot 2 go to bulb 1 and neutral 2 and hot 1 go to bulb 2. Here's the edited picture to make things more clear:
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Old 05-12-13, 08:24 AM
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Right.....technically all the switches will just be in the black wire but the neutral has to come along for the ride.
 
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Old 05-12-13, 08:27 AM
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Just edited my last post... does it seem more clear to you?
The neutral would not come along for the ride -- it's in a separate wire
 
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Old 05-12-13, 08:36 AM
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The neutral would not come along for the ride -- it's in a separate wire
If you mean separate cable then no you can not have the ungrounded conductor (hot) and grounded conductor (neutral) in different raceways (sheaths/cables).

Terminology: Wire is a single conductor. Cable is two or more conductors in a metallic or nonmetallic sheath.
 
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Old 05-12-13, 08:45 AM
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Just as an aside here......you'll need to be using three wire plus ground cable for the switches anyway.
 
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Old 05-12-13, 09:08 AM
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The neutral would not come along for the ride -- it's in a separate wire
Are you running cable or pulling wires in conduit?

Regardless of which it is, if your jurisdiction has adopted the 2011 cycle of the NEC then every switch box must have the system neutral in it. The only exception is for a switch loop, which would be difficult to do with three switches. Besides, it's a good idea to have it there for any device that needs it.

Also, regardless of the wiring method,
Originally Posted by ray2047
you can not have the ungrounded conductor (hot) and grounded conductor (neutral) in different raceways (sheaths/cables [or conduits]).
That rule is much older.
 
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Old 05-12-13, 09:15 AM
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Alright, I drew a diagram.
If the neutral cannot be in a different cable, this will not work?
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  #10  
Old 05-12-13, 09:20 AM
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The four way switch needs to be connected on both feeds with 3-conductor cable.

Tech note: The reason hot and neutral must be in the same cable is to cancel out electromagnetic fields so the wires don't over heat.
 
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Old 05-12-13, 10:32 AM
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If the neutral cannot be in a different cable, this will not work?
It might work, at least until the 2-conductor cable between the two light boxes overheated.

How are you planning to run two single conductors between the lights and the switches? By running 2-conductor cable and capping off the white wire in each? If so, the only money you're saving is the difference in the cost of 3-conductor cable vs. 2-conductor cable between the switch boxes. That's not a lot of money and, once you do it, you will have answered both of the concerns raised earlier: You will have the hot and neutral in the same raceway everywhere and you will have the system neutral in each switch box. Voila!

Why do you show the panel feed coming into the box for light 1? Is that a pre-existing condition? Because you could save the cost of one 2-conductor cable run if the power came into one of the boxes with a 3-way switch.
 
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Old 05-12-13, 10:45 AM
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The single wires would have been accompanied by wires for outlet power in those boxes.
I can understand why those wires would overheat, thanks.
Going the other way makes me have to add another 14-2 along with the 14-3 wires I'm adding over a distance of 25 feet, just because of how the switches are all set up.
And yes, it is a pre-existing condition. I have some wiring set up with a 3 way switch setup, but I'm adding a 4way and another light.
 
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Old 05-12-13, 01:05 PM
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I'm confused. It may be because I haven't been phrasing my questions as well as I would like to, or because new information emerges... I don't know, but let's try a bit more.

When you say
The single wires would have been accompanied by wires for outlet power in those boxes.
two things come to mind. The first is those boxes are outlets. Every box in your system is an outlet. So are you saying that you're planning to add a receptacle? In the same box as the first switch? And that you're planning to supply that receptacle with the same circuit that's supplying the lights? If you are, then both the "hot" and the "neutral" from the panel will both be needed there anyway. You'll have to run them both down from the light.

When you say "accompanied by wires for...," what wires are you planning to run between those two boxes?

Going the other way makes me have to add another 14-2 along with the 14-3 wires I'm adding over a distance of 25 feet, just because of how the switches are all set up.
You need to install 3-conductor cables to connect three switch boxes. In a fully compliant system, the white wires in those cables will be grounded conductors (aka neutrals). You may be able to re-use some 14-2/G that's installed now for other parts of the system.

You mention #14 AWG conductors. Is this a 15 amp or a 20 amp circuit?

And yes, it is a pre-existing condition. I have some wiring set up with a 3 way switch setup, but I'm adding a 4way and another light.
OK, so bringing the panel feed directly into one of the two boxes where there will be a 3-way switch isn't an option. Oh, well. You'll just have to extend it from the box for "light 1" to one of those wall boxes.

Are you talking about wiring for this set of lights and switches? If so, there should already have been 3-conductor cable between the switch boxes.
 
  #14  
Old 05-12-13, 02:04 PM
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Well, I'll be changing my plan now, since I can't run hot without a neutral next to it.
I was originally going to power both a receptacle and a light switch on the bottom left.
On the right, I'd have used 14-3 for a receptacle and the light power return.
On the top, there would have been 14-3 for the receptacle power, light neutral, and light power.
But since that won't work, it doesn't matter anymore -- I'll do it the correct way

Yes, it's 15 amp, not 20.

And finally, there is 3 wire cable there -- I was going to change it up.
 
  #15  
Old 05-12-13, 04:18 PM
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Regardless of which it is, if your jurisdiction has adopted the 2011 cycle of the NEC then every switch box must have the system neutral in it. The only exception is for a switch loop
There is no exception for switch loops in 404.2(C). That would kinda defeat the purpose of the change. There is, however an exception for raceways (provided the raceway is large enough to pull a neutral later) so it would in fact matter which one it was.
 
  #16  
Old 05-12-13, 08:49 PM
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I was originally going to power both a receptacle and a light switch on the bottom left.
You can do that. The only problem will be that that receptacle will be on the same 15A circuit as the lights. I don't see a compliant way to make the second receptacle work without 4-conductor (5-wire) cable between the switch boxes.

there is 3 wire cable there
I think this is part of the confusion. A 3-wire cable has two insulated conductors and one (usually) uninsulated conductor. 14-2/G is an example. A 3-conductor cable has three insulated conductors and one (usually) uninsulated conductor. 14-3/G is an example of that. A grounding conductor is counted as a wire in a cable assembly but not as a conductor, since it should only carry potential in the event of a fault.
 
  #17  
Old 05-12-13, 09:13 PM
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There is no exception for switch loops in 404.2(C).
Sure there is. Or there is as I read it, at least.

But I wish I'd said "The only exception is for a switch loop, and then only under certain circumstances."
Section 404.2 Switch Connections.

(C) Switches Controlling Lighting Loads
. Where switches control lighting loads supplied by a grounded general purpose branch circuit, the grounded circuit conductor for the controlled lighting circuit shall be provided at the switch location.

Exception: The grounded circuit conductor shall be permitted to be omitted from the switch enclosure where either of the following conditions in (1) or (2) apply:

(2) Cable assemblies for switches controlling lighting loads enter the box through a framing cavity that is open at the top or bottom on the same floor level, or through a wall, floor, or ceiling that is unfinished on one side.
You just have to wire it through an unfinished attic or basement or the wall that partitions off your utility room. Don't ask me why it's there, but it is. Maybe they're thinking it's easy enough to replace the cable if you need the neutral later? Kinda like pulling the grounded conductor into the raceway?
 
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