Not even sure if it's OK to do and, of course, local codes prevail.
OK, so you need to run a 15A 14/2 line to a load. All you have is 14/3.
In general, is it ok to use 14/3. Of course it's the same capacity but
what is the right thing to do with the red wire?
- Snip it off at both ends right at the sheathing leaving and using the
b/w/g as usual.
- Tape and mark as Not COnnected at both ends or something.
- I saw once where they took the red wire, bent it back to the sheathing
and curled it around it. Maybe some universal wiring message.
I know this is not clean and pro to do but why not? I thought about it
and said what if I were running cable to a ceiling fan on a wall switch.
The fan has no light. If one were to think ahead they would run 3-wire so
in the future addding a light kit or replacing the fan with one that has
a light would make it easy to change the wall switch setup to control
light & fan.
As long as you're fudging a little on the code anyway, I'd
red and black together, wrap it with tape so that only the black comes
and then use the black and white as a normal 14/2.
Nothing dangerous about this, except it violates "convention", but
the voltage drop a little. Obviously you would still use a 15A
Peraonally, I don't see the point in completely wasting a perfectly
extra run of copper.....
I would welcome any comments or criticism on this, just in case I
have overlooked something....
Andy in Eureka, Texas
I have done this many times. Your ceiling fan example is a prime example.
I ran 14/3 wires between the switch and ceiling light in all of our
bedrooms. For now, I installed wire nuts on each end of the red wire. But
if we decide to install a ceiling fan in the future, the wiring is there
and ready to go. By the way, if you're planning ahead for this, remember to
install a box rated to hold the weight of a ceiling fan, even if you're
only installing lights right now. Also, make sure your boxes have enough
capacity for the extra wire and nut.
I used 14/3 wires for our living room outlets. The red wire connects to a
wall switch, so I can quickly and easily convert any outlet to a switched
outlet by using the red wire instead of the black. For the rest of the
outlets, the red wires simply get joined and capped with wire nuts.
I also used 12/3 wire recently when I only needed 12/2. I had already
purchased 200' of 12/3, but needed one 15' run of 12/2. Rather than waste
money and wire buying a separate roll of 12/2, I simply used the 12/3 and
put wire nuts on each end of the red wire.
These were all been approved by our inspectors with no problems.
The NEC does not prohibit the use of a 3 conductor cable instead of a 2
conductor cable. The spare conductor should be capped with a wirenut and
identified on each end as spare. It does not create a hazzard or violate any
codes I am aware of. Inspectors all over the country will approve such an
installation as long as the conductor is rated for the load and the
protection is sized properly.
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