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I have 4 neutral wires bundled together, and two switches requiring neutral. Each switch allows an in and an out for neutral, as pictured. My question is, does it matter how I pair the neutral wires with each switch? If it does, how do I tell the proper wires to use?

Edit: I can't get the images to upload, hopefully there description is clear enough.

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    What part of the planet are you in? What size wire? – JACK Jan 7 at 16:43
  • What brand and model of switch I don’t remember one that needs a neutral in and out of the switch usually 3 wires for a single throw black hot , red switched hot and white neutral , double throw or 3 way switches may have an extra blue or black but I don’t think I have seen 2 neutrals needed. – Ed Beal Jan 7 at 16:50
  • I'm from US. And it's a GE Smart Switch model ZW4005. I'm probably wrong about the in/out for neutral wires. It's just that there are two holes to put the neutral wire into. – Gave Drohl Jan 7 at 16:57
  • I was going to make a joke about Foo Fighters with the first letters switched, but that didn't really get anywhere... – JPhi1618 Jan 7 at 18:21
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Bundled together sounds like the USA so you can run a neutral from each switch and connect them to the existing four neutrals with a red wire nut,if it's 14 AWG. A better way would be to install a neutral, white, wire from the first switch to the second switch and then from the second switch to the bundle of neutrals since you have an in and out for neutrals on each switch, provided that in and out are not backstabs but back screw clamps.

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  • The switches each came with a white wirei bet for that purpose, thanks! – Gave Drohl Jan 7 at 16:58
  • @GaveDrohl, wire nuts come in different sizes. The one the switch came with are probably only good for 2 wires. If you need to bundle 4-6 wires, you'll need a bigger one. – JPhi1618 Jan 7 at 18:22
  • @JPhi1618 Very true.... why I mentioned the red one. – JACK Jan 7 at 18:27
  • @JACK, I read his comment as the switch coming with a wire nut... I read it again and it looks like the switch came with a white pigtail wire, so nevermind! – JPhi1618 Jan 7 at 18:31
  • @JPhi1618 I'm just giving you a hard time.... you're usually spot on!!! – JACK Jan 7 at 18:48
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I gather you're a stone cold novice at electrical, and your only interest in it is DIY hooking up these smart switches.

The typical confusion we get with neutral wires is people seeing them connected together and thinking "they must be spares", and they think they're meant to pull out one of the neutral wires and use it for their smart device.

Not at all. Nobody runs spare wires in electrical*. You probably know electricity flows in loops. The neutral wire is the return loop. When controlling lights, it's good enough just to interrupt one side of the loop, so you interrupt the "hot" side for safety reasons. That is why plain switches don't need neutral.

(If neutral is return, what's the bare ground? Safety shield. Perfect world, current never flows on it.)

Now, your smart switch needs neutral to power itself. Switches already get "hot", and the switch needs neutral to complete the loop.

So your smart switch neutrals need to be added to the already bursting bundle of neutrals now present in the box. That's 6 neutrals under 1 wire nut - technically legal, but very challenging to assemble.

Therefore, I recommend you obtain a short length (6-12") of white wire, a pigtail. THHN solid #12 will suffice. Undo the 4-bundle, and remove one neutral (one that goes to one of your lamps), and add this THHN wire in its place. I hope I won't need to tell you to strip it similar to the other wires. There's no need to go crazy bending it to match the other wires; the wire nut will take care of that when you crank it down - and this one time, do use gorilla-tight not monkey-tight.

Then do a "pull test" - hold the nut and yank each wire in turn. If any wires come out, redo it, because the problem is bad technique. Never tape wires to keep them from falling out - that means you already have a bad connection, and that will start a fire.

Now you have this pigtail wire, the 1 wire you removed, and the 2 new wires from the smart switches. That's 4 (2 of which will be smaller) and these won't be hard to put under 1 red wire nut. The most loved brand is Ideal.

If you just can't hack wire nuts, then go with lever connectors. I recommend avoiding jab-in connectors; they create complicated problems.

If your stripper has a wire cut function, use it very sparingly - wire length is precious. I never cut to get fresh ends for wire-nutting, unless the stranded wire I use has gone full-on dreadlocks. You don't need fresh ends. The nut mostly takes care of it.


* (except now, all switch boxes must be wired with a neutral for smart switches, so where once upon a time an electrician could wire a switch box with no neutrals at all, now there must be one.)

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