I have a switch box in my kitchen that has 3 switches in it, but I’m looking to replace only one with a Wyze switch. The house was built in 2008 and the switch is the only one that controls a kitchen light. When I look inside the box, there is a messy jumble of lots of wires. I need help identifying my neutral wire, if possible. The switch that already controls the light doesn’t even have a ground connected to it, but I do see some bare wiring going into a block inside the box. I have a volt meter if that will help in any way. Thanks in advance.
The bundle of white wires is your neutral connection. Your current switch interrupts the “hot” line wire. You would connect the white wire supplied to that bundle. It’s not safe with the type of wire nut connector provided. You will need a larger connector or a block similar to the one in your junction box that would allow you to connect another neutral ( white ) wire.
Generally, Switch boxes do not have a neutral in the box. For an On/Off switch. Power is sent to the switch (usually on a black wire, but not guaranteed). The return power to the light is usually on the white of the 2 conductor Romex cable. You have red wires that indicate that 3 conductor Romex is used. Usually this is for 3-way switches. This is all that is absolutely needed for conventional wiring. Electricians try to get by with the minimal amount of copper conductors needed to save money on supplies. Do not count on white wires being neutral. In your last picture, you can see that incoming Power looks to be connected to several other black wires that presumably feed the individual switches. Usually an electrician will just jumper the incoming power from switch to switch, The white wires, all connected together, could indicate that neutral is indeed supplied to this switch box, but must be tested to be sure. Other white wires are carrying the switched-on power back to the individual light or ceiling fan, so they would not be connected together. Possibly, the connected white wires could be outgoing power to multiple lights on one of the switches. The position of the lights relative to the switch box made for a shorter wiring run by ganging the outgoing power together. With power off, you can use your multimeter to measure the resistance (Ohms Ω) of this white bundle to a bare ground wire. With power off, you can stick a sewing pin or safety pin (easier to push) into one of the ganged white wires to make a connection to the wires inside. This takes a bit of force and you can usually feel when the pin hits the copper wire. Insert the pin at an angle so that once through the insulation the pin tip will rub along the copper wire inside. Neutral and ground are tied together at your primary circuit breaker panel. If these are neutral wires, the resistance should be very low like 0.1 Ohm. This depends on how long the wiring is back to the main panel. If these neutrals and grounds are daisy chained along the way to the panel. The resistance could be slightly higher with old connections or bad connections between this switch box and the main panel. If you are comfortable with working on a live circuit with all 3 switches connected and hanging out of the box, well separated, set your multimeter to AC Volts in the 120VAC range. Connect your multimeter with gator clips so you do not have to use your hands with power on to make the multimeter connections. Connect one lead of your multimeter to the pin in the ganged white wires with a gator clip and make sure the pin is not touching anything else. You may need to tape your multimeter lead to something to keep the weight of the lead from pulling the pin out of the white wire. Connect the other multimeter lead to a bare ground wire in the box with a gator clip. Once setup this way, you should not need to put your hands in the switch box. Using protective clothing, turn the power on. Read the voltage between the bundled white wires and the bare ground wire. With the meter connected as stated, flip the switches to each position and watch the voltage on these white wires in each condition. Be careful holding the switches, top to bottom, with one hand while flipping it with the other. I personally know how to work on live wiring with some precautions and protective gear. Before applying power, make sure no exposed wiring or screw heads on the switches are touching anything. Wear rubber soled shoes and the thickest rubber gloves you have. I would not use thin surgical gloves. Kitchen dishwashing gloves are heavier and extend up your arm. Make sure no part of your exposed arm above the gloves rubs against a screw head on a switch. If you get a line power voltage reading in any switch condition, those white wires are not neutral. I do not recommend getting near an open switch box with power on unless you really know what you are doing. I have done this for 50 years on household level voltages. I have brushed up against a hot connection several times. With rubber soled shoes, you are not connected to ground (don’t stand in water either), so the 120V power has nowhere to connect to through your body. When I have brushed up against live household power, it will send a sharp tingling up your arm causing you to jump back, but should cause no damage unless you have an electronic device in your body such as a pacemaker or other device. If you have such a device in your body, DO NOT work on open live household power circuits!!! Once testing is complete, remember to switch the power for this circuit off again at the power panel.
I agree with testing, and in a similar situation (replacing two switches in a 3-gang box with smart switches) have used a non-contact voltage tester to determine which of the black wires going to a regular single-pole toggle switch is LINE (live, coming from the power source and breaker box) and which is LOAD (going to the light fixture). If you have a multimeter, you could carefully use that, as well.
As @jeffmyatt suggested, you’re most likely going to use the Accessory Wire that came with your Wyze Switch to connect the Switch’s Neutral terminal to the bundle of white wires in the box, but as @MillBilltheWise suggested, it’s a good idea to test.
