I would like to replace an existing analog light switch with a wireless one. The new switch requires a neutral electrical connection to work. There is no neutral connection at the existing switch, only two wires: live and switched-live. Would it be possible to string an additional wire through the stucco wall with the use of, say, a snake used for opening clogged drains?

The junction box is located about three feet (almost) directly above where the switch is in the wall.

Also: the existing wires are stiff copper ones. Can I use a more flexible kind of wire for the new neutral connection? Specifically, can a wire be capable of carrying high current, yet be flexible at the same time?

  • Does the junction box have a neutral wire? Or would you need to pull it from the main panel?
    – mmathis
    Oct 19 '16 at 20:03
  • @mmathis Junction box has neutral.
    – Sabuncu
    Oct 19 '16 at 20:51
  • 1
    Can you post photos of the insides of the junction boxes? Also, where in the planet are you? Oct 19 '16 at 23:06
  • @ThreePhaseEel I can't post the image now but will do so later to update the question properly. I am in Turkey, 220 v.
    – Sabuncu
    Oct 20 '16 at 7:55

You may only use wire which is legal for wiring in your country (I am presuming USA and thus National Electrical Code). The NEC allows many types of wire, but as a practical thing, it boils down to two types: Multi-conductor cable, typically NM aka Romex; and single-conductor wire used in conduit, typically THWN.

You are dealing with solid wire, which is stiff. For a much more flexible wire, stranded wire is available. However, Romex is not available in stranded. Each of your devices must be rated for the strandedness of your wire. (for instance "back stab" connections found on very cheap components are rated for solid wire only).

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Neutral must be in the same multi-conductor cable, or the same conduit/raceway, as the other conductors. You cannot retrofit a neutral to a multi-conductor cable.

If those boxes are connected by conduit, then each of the wires is a single conductor. You can simply pull (or shove) an additional neutral wire through the conduit.

If those boxes are connected by flexible cable, then you will need to pull an entire, additional multiconductor cable between the two boxes. You have two ways to go.
- Pull a 12/3 or 14/3 cable to replace the existing cable. This will include hot, switched hot, and neutral.
- Pull an additional 12/2 or 14/2 cable alongside the existing cable. Cable A will carry always-hot and neutral for the switch and lamp. Cable B will carry switched-hot and neutral for the lamp. This means when the switch is on, neutral will make a seemingly redundant round-trip between the boxes. This is required by Code, and for good reason.

You don't need a plumbing snake. They make "fishing tape" specifically for electricians, used for a variety of hat-tricks to route flexible cable through existing finished work in residences. Generally in commercial work, everything is in metallic conduit, so any conduit they plan to use must be installed before walls are finished.

If you are starting into electrical work and plan to stay awhile, I'd encourage you early to get acquainted with your local Electrical Supply House. This is the sort of place that's open from 7am to 6pm and at 7am, the parking lot is full of electricians' trucks. Electricians are smart people and are perfectly capable of finding the local Home Depot; they buy from electrical supply houses because the pricing is roughly equal and the support and selection is a LOT better.

  • I never thought about the option of just replacing the existing wires. I was fixated on "adding the missing wire" - thanks for your visionary approach. Few comments: No Electrical Supply Houses or Home Depots here, but there is Bauhaus, a German brand that is the equivalent of Home Depot. Fishing Tape cannot be found here. If you showed it to me before this answer, I would not have known what it was. (Now I know, and will get one on my next trip back to the U.S.) I don't understand what you mean by the cable A and B configuration, but I'm studying it now - will post a follow-up comment.
    – Sabuncu
    Oct 20 '16 at 9:39
  • Also: I am starting with electrical work, as you put it, but I am very apprehensive. Basically, I am afraid of electricity. I want to make sure and research any electrical task before I even attempt to think about doing anything.
    – Sabuncu
    Oct 20 '16 at 10:04
  • Bauhaus is your version of Home Depot. But there must be something like a proper electrical supply house. It may not be called "fishing tape" but it is a narrow strip of metal or fiberglass that can be snaked down walls. Obviously the better ones are fiberglass, as that does not conduct electricity. Sometimes you can use the old cable to "pull" the new cable, but only if it is not attached inside the wall - most electrical code calls for it to be attached. Since you're in greater Europe I would stick to EU electrical codes, most non-EU countries are harmonizing to that. Oct 20 '16 at 23:09

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