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Last Saturday I was trying to replace switches.. but the outcome didn't work the way it was supposed to.

I have 3 switches that all 3 go to the same light.

Switch A. 1 cable coming into the box. All 3 wires (black, red and white) are hot.

Switch B. 2 cables coming into the box. This is a 4way switch. Since those are set up straightforward, I just wired this. (black and red (from cable 1) in, black and red out (to cable 2)).

Switch C. 1 cable coming into the box. Only black and red are hot.

I'm not an electric-savvy person, so I'm afraid to hook up switch A with black going to the black bolt and the other two as the travelers, because.. I don't know if that will be safe, since they're all hot. Same with switch C: Not sure what to put where.....

I hope someone can help me out with this.. (currently simply having the power off for those switches isn't really helping anything..)

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    Next time the best advice is to take pictures before undoing any wires. I know some electricity but three and four switches confuse me also. No pictures and diagrams and I am lost.
    – crip659
    Jun 12, 2023 at 19:23
  • Do you have the ability to put it back the way you found it? Or is that information lost? FYI there is no standard diagram for a 4-way. There are at least 8 different ways to wire a 4-way, and I stopped counting. Jun 12, 2023 at 19:24
  • @Harper-ReinstateMonica I have an app that shows diagrams, and it only shows 2. Both of which have 2 cables coming in on both of the 3way switches, which is normal. But of course the clown that did my house didn't do that... I only have taken a pic of the one switch that has 2 hot wires. I don't have a pic of the other, so no.. unfortunately no....
    – Malachi
    Jun 12, 2023 at 19:50
  • @crip659 Ha yes. I only took a pic of the 4way (but that's a simple one) and a pic of the one that has 2 hot wires. Dont have a pic of the one that has 3 hot wires.....
    – Malachi
    Jun 12, 2023 at 19:51
  • If you are using Non contact tester then STOP, get a multimeter.
    – Traveler
    Jun 12, 2023 at 20:05

1 Answer 1

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Below is an illustration of how a 4-way switch diagram works.

Notice that the common wire is not included in the diagram - that's because it complicates the explanation because the power source may be coming from one of the switch boxes, or from the light box, itself, which would change how things are wired.

Notice in the diagram at the very bottom that the common wire (white) travels throughout the circuit and remains uninvolved with the switches, but connected together throughout. This is ideal, but rare because it requires specific circumstances (2 lengths of 3-wire cable, 2 lengths of 2-wire cable, and the source and load to be on opposite ends). Practically speaking, electricians sometimes do not have both 2 and 3 wire cable on hand, and the power does not always come from the convenient/simple side of the house.

If I were you, I would do the following:

  1. Go buy some way to label the wires like these wire labels.
  2. Go buy a multimeter (some are very reasonably priced like this one.
  3. Take out an extension cord that will reach between all switches and the light.
  4. Turn off the power.
  5. Disconnect every wire that was connected to the switches and light. If there are any wires just connected together and not connected to the switches or light, leave them connected together. Or, if there are any wires connected together and then to a light or switch, disconnect them from the light or switch, but leave them connected together.
  6. Use the multimeter with the extension cord to extend the reach of the multimeter by connecting the ground on the extension cord to one wire, and then go around to each other box with the other end of the extension cord and the multimeter set to read resistance (ohms), and find where that wire goes by touching one contact of the multimeter to the other end of the ground on the extension cord, and the other contact on every wire in every other box, until you find out where it goes. Label them with the same number. It starts out tedious, but as you find matches, the remaining "unknown" wires dwindle until you're left with the "line"/power in, and "load"/light.
  7. Draw a diagram of what wires you have, and where they're connected. For example:
  • Box A has "unknown" wire, (1) wire, and (2) wire
  • Box B has (1) wire, (2) wire, (3) wire, and (4) wire
  • Box C has (3) wire, (4) wire, and (5) wire
  • Box D has the light/load and (5) wire, and "unknown" wire
  1. Looking at the diagrams at the bottom, you should be able to figure out how to then wire those boxes. If not, re-post with that information, and people here should be able to help you.

Stay away counting on the colors. General residential guidelines suggest using white as common, black as hot, and red as switched, but as you can see from the diagrams, that is not always the case by necessity. And, moreover, it may not be the case out of convenience (sometimes people will use white as a carrier because they only need a 2 wire, and they generally don't make a 2 wire romex with only black and red) If they use the wrong colors, it's good practice to tape the end of the wire right before the connection with the right color, but I don't think it's code, and even if it is where you are, they might just not follow the code. Every single connection is not always inspected.

I hope that helps.

How a 4-way switch circuit works

enter image description here

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  • marking white where it's not neutral is required by code.
    – Jasen
    Jun 13, 2023 at 3:22

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