Quickie - 3 vs. 2 wire


  #1  
Old 01-08-04, 10:13 AM
AnklBytr
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Quickie - 3 vs. 2 wire

When wiring my basement ceiling fan/light I ran 2 14/2 wires to the outlet. Should I have run a single 14/3? Does it really matter code wise or is it just a convenience?

Thanks!
 
  #2  
Old 01-08-04, 11:00 AM
J
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Yes, you probably should have run a 14/3. I'm not quite clear on the two 14/2 thing. I've heard some argue that running two neutrals between the switch box and the ceiling box violates code, but I'm not convinced. There's also the conductors in the same raceway issue. These are gray areas to me.

If it's easy to change it out, do so.
 
  #3  
Old 01-08-04, 11:41 AM
AnklBytr
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Thanks! I'll go ahead and re-wire.

What means "conductors in the same raceway"? That's true all over the basement prewire. In some cases we have 4 wires running along the same 2x6 stud (which passed inspection with the builder). I live in Charlotte, NC. No conduit required that I'm aware of.

Hey, on a completely different note. If there are few very minor nicks (approx 2mm) in the outer casing of the romex (from those darn staples) does that present a hazard in any way? None of the inner casings are touched.
 
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Old 01-08-04, 12:15 PM
R
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I believe I can shed some light on the dual 14/2 vs single 14/3 issue.

What matters is the connections available from the fan/light, and how you connect them.

When you have two wires in parallel and try to run current through them, the current will split in half, with half the current going down each wire. This may not be exactly in half, as factors such as wire length and the quality of the connection make a difference, but for our discussion assuming half in each wire is close enough. The mismatch will come into play because the two hot wires will not have the same current.

If you have two cables and if the connections to the fan and light are completely independent of each other (there are two neutrals coming from the fan/light) then you don;t have problem. However, if the fan/light has a single neutral then there is a mismatch.

Is it a big deal? Probably not.
 
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Old 01-08-04, 05:11 PM
AnklBytr
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In my case I have 2 separate neutrals/hots coming from different wall switches.

If 3-wire is the "right way" then I'll re-do (wouldn't be the first).
 
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Old 01-08-04, 06:18 PM
R
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The switches are on the same circuit breaker, aren't they?
 
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Old 01-08-04, 06:22 PM
J
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The concern is heat. I don't really understand it much, but it has to do with the magnetic fields created by flowing current. Ideally, the current flowing in one direction in a cable exactly equals the current flowing in the other direction in the same cable. You can see how this is true in most wiring, and will be true once you convert to 14/3. But it is not true in two runs of 14/2.

Use the 14/3 and we won't have to hurt our heads thinking about it.
 
  #8  
Old 01-08-04, 09:19 PM
P Michael
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If they are bundled together, there should be no problem.
~Peter
 
  #9  
Old 01-09-04, 04:11 AM
AnklBytr
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Yes, they're on the same circuit. I'm going to re-wire in the following way:

Current config:
power in, power out, pig tails to 3 switches.
one switch goes to can-lights on dimmer.
one switch goes to fan control.
one switch goes to fan/light control.
(all on separate 14/2 wires)

Based on the comments in the forum I'll change to:
power in, power out, pig tails to 3 switches.
one switch goes to can-lights on dimmer.
one switch goes to fan control.
one switch goes to fan/light control.
(fan light/fan control will be changed to a single 14/3 wire)

Sound good?
 
  #10  
Old 01-09-04, 07:28 PM
P Michael
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On secomd thought, it all depends on how the fan/light combo is arranged. If it has two white wires [neutral], then you have to have two 12-2 or 14-2 cables. If there is only one white wire and separate leads for the lights and fan, then you should go with 14-3.
If you attach two 14-2s to the thing and there is only one white wire coming out of it, you would end up creating parrallel conductors which you can't do unless both wires are size #1 [1/4" thick]. I don't think you need that.
~Peter
 
  #11  
Old 01-10-04, 04:57 AM
AnklBytr
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Thanks. This supports changing out the 14/2 for 14/3 since most fans have a single common white.

Thanks again for the input.
 
 

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