12/2 or 12/3 NM Cable?

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xformer said:
Is there any physical advantage of using 12/2 or 12/3 when meeting 404.2 C requirements?
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I cannot imagine any, the sheathes and insulation are the same AFAIK.

12/3 merely contains an extra conductor.

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.
 
Yes. If the circuit (or branch thereof) is not supplied through the switch box, you'd need (at least) 3 conductors?hot, switch leg, and neutral?run to the switch box.
 
Smart $ said:
Yes. If the circuit (or branch thereof) is not supplied through the switch box, you'd need (at least) 3 conductors?hot, switch leg, and neutral?run to the switch box.
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Agreed... I was just wondering if there was any wiring advantage to either switch first or box first as far as conductor fill or cable runs.
 
xformer said:
Agreed... I was just wondering if there was any wiring advantage to either switch first or box first as far as conductor fill or cable runs.
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IMO, it is much easier for everyone when the switch box is fed and just a return to the light-- at least in a residence. You generally don't see that commercially
 
xformer said:
Agreed... I was just wondering if there was any wiring advantage to either switch first or box first as far as conductor fill or cable runs.
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General guideline, IMO...

If fed from below, run through switch box.

If fed from above, hit light box first, then 3C to switch box.
 
If the power is coming in from the light, you need two conductors for switch leg plus a neutral if the switch is in one of the locations that require it.

Tapatalk!
 
xformer said:
Is there any physical advantage of using 12/2 or 12/3 when meeting 404.2 C requirements?
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12-3 is easier to pull. That's it.

Don't forget exception 2.

(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.
 
xformer said:
Is there any physical advantage of using 12/2 or 12/3 when meeting 404.2 C requirements?
Click to expand...

Some people use either 12-2-2 or 12-4 when pulling for a 3-way switch. But here it is not stocked and would have to be ordered.

To be honest, I don't really understand your question. If you pull 12-2. you would have to pull two cables to comply. 12-3 would meet the needs of the extra conductor for the switch box requirements. This of course is just for a SP switch. If a 3-way, you would have to do something like I mentioned in the first paragraph. And all of this also depends on whether you can/can't use either of the exceptions.
 
At the risk of learning something:)

Why would you need a neutral in a switch box if it were fed from the light? All you need is power and switchleg/s. And a ground.

If it were fed through the switch box a neutral is going to be passed through. Which is the way I do it.
 
J.P. said:
At the risk of learning something:)

Why would you need a neutral in a switch box if it were fed from the light? All you need is power and switchleg/s. And a ground.

If it were fed through the switch box a neutral is going to be passed through. Which is the way I do it.
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402.2(C) to help you get on the same page.
 
J.P. said:
At the risk of learning something:)

Why would you need a neutral in a switch box if it were fed from the light? All you need is power and switchleg/s. And a ground.

If it were fed through the switch box a neutral is going to be passed through. Which is the way I do it.
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To answer your question, there are devices such as occupancy sensors, dimmers, etc that require stand-by power which needs a neutral. In the past these just used the EGC for the neutral power. They draw very little power and the thought was it was ok to use the EGC for the neutral. Now (2011 and later) a real grounded/neutral is required for these devices. This is to keep unwanted current off the EGC and any metallic paths.

Edit: Even though a standard SP switch is installed, the thinking is one of the devices may be installed later and they want the neutral to be there if needed.
 
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Little Bill said:
Some people use either 12-2-2 or 12-4 when pulling for a 3-way switch. But here it is not stocked and would have to be ordered.

To be honest, I don't really understand your question. If you pull 12-2. you would have to pull two cables to comply. 12-3 would meet the needs of the extra conductor for the switch box requirements. This of course is just for a SP switch. If a 3-way, you would have to do something like I mentioned in the first paragraph. And all of this also depends on whether you can/can't use either of the exceptions.
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there really isn't any need for special wire like 12-4 anymore as you just make a 3 Way or 4 Way by starting at 1 point feed through and the neutral passes with the 2 travelers all the way to the light switch. I can understand existing situations but we're talking about new. For the most part we need to quit using the hot at both ends method.
 
ActionDave said:
As far as I know California Travelers are only standard practice in California. There are a few Californicators that try to bring this style of wiring into my state; they are dealt with on a case by case basis.
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That's good.
Those kalifornians need to be schooled.

Hopefully if I come that way you won't give me a hard time. :thumbsup:
 
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