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This outlet is two rocker switches. Left controls my bathroom light (4), right controls my bathroom fan (3). I am trying to install a timer switch so the fan is only on for ~30 min at a time.

The instructions insist a neutral wire is connected to the switch.

My house was built in the late 60s. Many of the wires have paint on them which makes things difficult.

The wire nut under (1) contains wires which come from the wall and don't connect to the existing switches. They are an egg-cream color which I believe is white + age. All the other white looking wires are black wires that have paint on them. I think what's going on with the wire nut in 2 is that the hot line from the wall is joined with two other small wires, one for each switch.

My thought is that (1) is the neutral wire, and I should undo the existing wire nut, add an additional wire which will goto my new switch as a neutral, then wire nut them all together.

Is that correct? Is there anything else I can do to verify this? What's the risk if I'm wrong?

(note 3 is the actual timer switch, once I realized I didn't know what the neutral was I took the pictures and then put it back how it started)

(edit: additional note, this bathroom has a small room for shower/toilet, where this picture is, connected to the area with two sinks... basically the other side of the wall in the same position is a gfci outlet by the sink)

Wiring Picture

  • Welcome to Stack Exchange. There are tons of excellent questions with pictures on these very questions. Definitiely read up and get comfortable. We are talking about voltages that can kill, and you asked just the right questions to make it obvious you know enough to be dangerous but also dont want to be Darwin in the process!!! In the picture it appears you are using backstabs, (where the wire is pushed in vs. screwed down - please do not use these). Also, the white is PROBABLY Neutral (99.99% so), but, to help us answer, do you have a meter and know how to use it??? – noybman Dec 30 '19 at 6:24
  • Here's a helpful one with lots of great advice, and pictures, and while it's a different application, there is much here that explains it all: diy.stackexchange.com/questions/155964/… – noybman Dec 30 '19 at 6:54
  • I do have a multimeter, but I don't know how to use it other than using it to test the voltage coming out of an outlet. And yes, your comment is correct --- I kinda-sorta know how this works (based a lot on reading other posts), but I know that it's very dangerous. Probably the most important thing I wanted to get out of the post was how to test they are neutral and/or what would go wrong if they weren't. – poisedsquirrel Dec 30 '19 at 16:40
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Yes, #1 is your group of neutrals and you would need to pigtail into that connector with a piece #14. Naturally, you want to shut off the breaker before doing any work. You're going to have to be careful arranging the existing wires so you can get the new timer switch into the box, and even then, you might need to add a box extender.

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  • I agree with Jack all those whites are the neutrals for the circuits. – Ed Beal Dec 30 '19 at 15:32
  • Thanks. And I will shut off the breaker, of course. The breaker in my house wasn't labeled and seems kind of illogical (so the efforts to label it thus far hasn't gone that well since its not clearly like room by room) so this part always takes me like 4x the time to do any other work. – poisedsquirrel Dec 30 '19 at 16:49
  • I held off on answering because A.) it is possible the whites are not neutral (like a hundredth of a %1 or less), but also 2.) because no grounds are seen in the picture, backstabs are used, and it looks like the insualtion on a white wire is bare and exposed as well as undetermined routing of black... (E.g., the switch on the right doesn't seem to be fed from #2, and it "should be") – noybman Dec 31 '19 at 0:56
  • @noybman Grounding wasn't required when this wiring was done. Those are not back stabs but back clamps tightened by the side screws. There is a wire going from the switch to #2. but we don't know the rotation of the switch. – JACK Dec 31 '19 at 1:30
  • @JACK ohh, if those are clamps then all good for sure. When did grounds get introduced as required? I thought NM form mid 1960's (like 1965) introduced ground wire? – noybman Dec 31 '19 at 2:42
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They also make timers that don't use neutral wires. Same company, same shelf.

They wire up exactly like your old switch, and are guaranteed to work anywhere a plain switch works.

These have a dial you twist and set to the exact time you want, and a spring and clockwork mechanism makes them unwind. They come in any range from 5 minutes to 12 hours, with or without a "stay on indefinitely" position. (At the lodge I use the ones without the "stay on" function, because the point is to stop people from leaving things turned on.)

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  • Great alternative! – noybman Dec 31 '19 at 1:01
  • Thanks. I actually looked for these not realizing neutral was a factor, but because I thought it might be cheaper but didn't find any. I have in fact found some online for ~10$ instead of ~$25, so that plus avoiding this neutral situation might be the ticket. – poisedsquirrel Dec 31 '19 at 3:26
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Check if a blue wire (CENELEC) or white wire (NEC). Be carefull to identify "switch loops" those may have a neutral-colored wire actually used for live.

A simple contact test-light will tell you if a wire is live or not, switched loops go from 0 to live potential after switch is operated, so testlight is off if switch is off and on if switch is on.

You can identify those by checking if a live wire is enetering the switch and a neutral colored wire is coming out of it.

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    Switch loops would not have a group of 4 white wires connected at a switch box. See @jack answer it is correct. – Ed Beal Dec 30 '19 at 15:34
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I believe that up until the NEC 2017 version, neutral conductors were not required in a box with switches in it. So the only reason there would be a neutral present would be if the circuit fed through the box. From what we can see of the box, it appears that the lighting circuits are fed to the light fixture first and the a line leg is sent down to the box and a switch leg is fed back to control the light. Since most NM comes with a white and a black conductor, white does not always indicate a neutral.

The bundle wires you have labeled 1, have a green wire nut on them. That would indicate that they are a ground. Then again it could be the neutrals with an incorrect wirenut on them.

So unless you can use a voltmeter to find 120V power between a line side conductor and another conductor other than the ground wires or verify that the #1 bundle are the neutrals. I would guess that there is no neutral in the box.

Good luck

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    With a name like retired master electrician I would expect a better answer, a group of white wires in a switch box, come on , code required or not. Green wirenut in a metal box with no visible grounding conductors. This wiring method Is at least pre 70’s. – Ed Beal Dec 30 '19 at 15:44
  • One of us is color blind, I don't see a green wire nut. It looks like an old tan twister. – JACK Dec 30 '19 at 15:49
  • It's not green. My impression in person was that it was clear and super dirty. – poisedsquirrel Dec 30 '19 at 16:56
  • @JACK - I'm the one who's color blind. Not a joke fact. – Retired Master Electrician Dec 30 '19 at 21:51
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    I'm upvoting the answer because "code be damned" we cannot know who wired that box as it is today, and just because it looks like the white is the neutral bundle, do any of us on the internet know it is??? All it takes is one idiot to have wired it before and then all bets are off. (but again, 99.99% it is!!! lol) – noybman Dec 31 '19 at 1:00
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There are only a few ways this can go

There are only four ways switches ever get wired:

  1. Power-to-the-switch, where always-hot and neutral are brought to the switch location, the switch breaks the hot, then switched-hot and neutral are brought from the switch location to the outlet location
  2. An "old-style" switch loop, where always-hot and neutral are brought to the switched outlet, with neutral terminating there, but always-hot carrying on in another cable to the switch location, which breaks hot, leaving the switched-hot to run back with the always-hot from the switch to the outlet
  3. A "new-style" switch-loop, which works as before, save for the fact that neutral is run on from the switched outlet to the switch location and capped off at the switch (since a Plain Old Light Switch has no use for neutral, but fancy doodads like dimmers, timers, wifi/... switches, and occupancy sensors can make productive use of it)
  4. Or a traveller spur, where either always-hot or switched-hot and the travelers of a 3-way setup (with multiple switches controlling the light) are brought from one 3-way location out to the other, instead of having always-hot come in one end of the 3-way and switched-hot come out the other

Since this is a single-pole situation (only one switch controls the fan in question), we can rule out #4. #3 can be ruled out by the lack of any wire colors other than white or black in the box, given that the wiring is done using cables, with their fixed internal color scheme (instead of individual wires in conduit, where one has the power of the rainbow at their disposal). We then rule out #2 in your situation because that requires a white wire to be attached to a hot terminal on a switch, and that's not the case; instead, all the white wires run into a bundle (nut 1), alongside a bunch of bundled black wires (nut 2) (although they're partly masked by white paint/drywall-compound splatter), which means we have case 1, and the bundled white wires must be the neutrals.

So, you can add your new timer's neutral to the existing bundle, alongside all the existing wires. Note that you may need to upsize to a larger wirenut to do this if the existing wirenut is too small for the new bundle of wires.

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