How do I know if this switch box has a neutral wire?

Question

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)

Answer 1

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.

Answer 2

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.)

Answer 3

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.

Answer 4

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

Answer 5

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.