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I am wiring a new screened in porch to include a receptacle, ceiling fan and 2 light fixtures. I am tapping into an existing 20A circuit. The starting point is 12/2 coming into a 3 gang box. The physical layout is

3 gang box -> light 1
           -> [[(receptacle) -> fan -> 2 gang box -> light 2]]

In other words, the 3 gang box contains switches for the ceiling fan (regular on/off switch) and two 3-way switches for the two lights. From this box, one of the lights (light 1) is connected with 12/2. The rest go through 3/4 PVC conduit outside into the screened in porch. The receptacle is un-switched.

First on this conduit run is the un-switched receptacle. Next comes the fan. At the other end of the porch is a 2 gang box with 3 way switches for the two lights (so I can turn them on from inside or outside). After this 2 gang box we end the run with the last light.

Since I am in conduit is it legal to do this (all 12g wire):

  • 1 Hot (un-switched) to receptacle
  • 1 Hot (switched) to fan
  • 4 travelers between the 2 2-way switches in each box
  • 1 switched hot from 2 gang box back to light1
  • 1 switched hot from 2 gang box to light2
  • 1 neutral that connects to receptacle/fan/light
  • 1 ground that connects to receptacle/fan/light.

This needs to pass inspection since it all falls under a building permit. My main question is the neutral - Do I need to run dedicated neutral wires for the receptacle, fan and light through the conduit? Or can I have them "share" one? I heard a rule that "each hot must have a neutral" but that that it didn't apply with conduit?

Thanks

  • All of the new stuff will be on the same circuit? – mmathis Oct 2 '17 at 18:26
  • If by "same circuit" you mean only one switch on the breaker panel shuts down the whole thing, yes. All of this branches off of one 12/2 wire coming into the 3 gang box. – mike b. Oct 2 '17 at 18:30
  • Switch loops for simple mechanical switches do not need a neutral and neutrals formerly were not installed. However, since new types of switches are powered devices which require a neutral, new editions of the electrical code might require a neutral to be installed when the circuit is initially wired, even with simple mechanical switches. In this case the neutral would be unused and would be capped in the switch box. Someone with a knowledge of the code will no doubt answer this. – Jim Stewart Oct 2 '17 at 20:09
  • You could just buy a book of Brady number tags. Then just number your wires. That way you could use the same color wire if you want. Not as easy to identify at first glance but then you won't be stuck with a spool of pink wire or some other color you don't need. – ArchonOSX Oct 2 '17 at 20:51
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Yeah, that's fine.

However you are going to lose your mind if you don't color-code. Get your lengths, then phone around to electrical supply houses for one that'll give you better price-per-foot wire than the atrocious big box prices. Or just buy several colors of tape to mark wire ends. I would go

  • Neutral: white
  • Always-hot: black
  • switched hot to fan: red
  • messenger group 1: yellow (both messengers can be the same color, no need to distinguish them)
  • messenger group 2: orange
  • switched hot back to light 1: blue
  • switched hot to light 2: red

Or any other colors, only rule is hots can't be white, gray or green.

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    @Jimstewart I believe so, yes. Regardless, OP must run neutral all the way to lamp 2. – Harper Oct 2 '17 at 20:19
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    You can add a neutral by attaching it to any other conductor in the existing conduit and a same color conductor to replace the existing conductor. Then just pull two for one. I might recommend you keep a little wire lube just in case pulling gets tough. – Retired Master Electrician Oct 2 '17 at 20:25
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    Yes, neutral will go all the way through to light 2 at the end of the conduit. I just want to avoid pulling 'extra' neutrals if not necessary. – mike b. Oct 2 '17 at 20:29
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    @JimStewart -- you nailed it re: 3-way "normal" convention – ThreePhaseEel Oct 2 '17 at 22:17
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    @JimStewart only if you're OCD. For instance every 3-way I have ever had the rights to take a screwdriver to, is off if all switches are down. Just install it, and if your OCD flares up, go turn the power off and swap messengers in one place. Doesn't matter where. – Harper Oct 3 '17 at 3:49

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