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I’m trying to replace the light switch in my bedroom and fix the outlets in the living room, but there are 5 separate lines and I don’t know what goes to what. I only have 1 light in my bedroom which is directly above the only switch in the room, and on the other side of this wall is my living room, which has only one switch and one light. The outlets on that side don’t work but they do in the bedroom. I took a few pictures of the light switch in the bedroom before I undid all the wires, and in the process of taking the switch out I broke the wall box it was in so I’m doing a quick temporary replacement of that as well. I’m afraid to turn the power back on to the house until it’s all put back together but again, I’m not sure how to wire it. Please help Switch before I undid it

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  • How about some pictures of what it looks like now?
    – JACK
    Jul 30, 2022 at 1:14
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    Major points for taking a "before" picture, though. Jul 30, 2022 at 2:40
  • Thanks for posting a good photo - it reveals some issues that definitely need to be fixed. 1) Only 1 wire can be secured under each screw on the device, so the 2nd black wire attached at the bottom left (with the end "hook" backwards) should be removed and instead combined with the other 3 black wires in the bottom red wire nut. 2) There is bare wire sticking out of the red wire nut on the bottom, and the insulated parts of those wires are not twisted/spiraled together, so that nut has not been tightened enough and the bare wire ends going in were probably too long or wrongly twisted.
    – Armand
    Jul 30, 2022 at 2:40
  • 3) Insulated white wires coming out of right wire nut also not twisted together, so that nut also not properly tightened/installed. 4) Bare copper ground wires not all connected together - 3 from the 3 top left white cables are twisted together with a copper crimp ring, so good. Bare copper wires from the other 2 white cables (top right and bottom right) need to be properly connected to each other and to the group of 3 wires that are crimped together. Keep that one copper wire connected to ground screw on the device. I'm not sure of best way to connect the 5 ground wires in this case.
    – Armand
    Jul 30, 2022 at 2:48
  • Electrical code note: this wall box may not have enough rated volume for all those wires; experts here will know better.
    – Armand
    Jul 30, 2022 at 2:51

1 Answer 1

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Somebody bodged it up, not terribly, but not good.

  1. two wires under one screw on the switch, not good and not code legal. The correction for this is to remove the wire going into the cable (top middle), and connect with the other black wires in the wire nut in the lower middle of the pic since it's already pig tailed (a very short wire from the wire nut to the switch).
  2. The cable coming in from the lower right is coming thru a hole that was obviously drilled in the box, altering a UL listed product. Again, not code legal.
  3. The ground wire from that cable was lazily wrapped around the existing ground without a proper crimp sleeve. Obviously this cable was an "add on".
  4. Having all the neutrals (white wires) tied together is common and OK. The only issue could be if one or more of them have a poor or non-existent connection.
  5. I disagree that you can solve this with a non-contact voltage detector. They can be very miss-leading.

Lastly, I would suggest a multi-meter and start tracing circuits. You can do that with the power off (and must), but with a non-contact voltage detector, the power needs to be on. My recommendation, EDIT (Thanks Jason) Test resistances first, being sure the power is off, record the readings per wire/cable pair, then plug in a something like an incandescent light bulb, space heater, anything that uses real power (not LED or LCD bulbs) Then test again for resistance (ohms) between each black and white wire on the same cable. Record and mark them, maybe using a sharpie and masking tape. If some are not near infinite resistance, those cables are going to lights. At any rate... After testing for voltage again, If one of them drops to near zero resistance, you found that circuit. Repeat until you've tested all circuits.

EDIT: Forgot to mention to get access for the continuity checks, you'll need to undo the white wires under the red wire nut, but that shouldn't be a problem to reconnect, since it seems as if all the white wires are already connected. Next, the sloppy ground should also be corrected with a proper crimp sleeve.

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  • As I should have noted in my comment above, I mentioned the non-contact voltage tester just to double-super-verify power is off on all the wires exposed there (sometimes there's a path to another circuit whose breaker has not been shut off and live power is still accessible). Thanks for pointing out that the non-contact tester is not for identifying circuits here.
    – Armand
    Jul 30, 2022 at 7:11
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    it's posslbly better to instead of a shorting plug use a high wattage appliance like clothes iron, a sandwich toaster or immersion heater - such a device won't cause so much excitement if you find a live outlet with it.
    – Jasen
    Jul 30, 2022 at 11:21
  • @Jasen That's a great suggestion. I'm going to update my answer based on that input! Thanks. + Jul 30, 2022 at 12:09
  • "Having all the neutrals (white wires) tied together is common and OK" - No! Only after verifying that there is only one supply into the box. It is entirely possible (and totally code-legal) to have multiple circuits in a single box. Joining unfused neutrals from different circuits could lead to an undetectable overload and fire.
    – nobody
    Jul 30, 2022 at 13:24
  • That is a fiber box and the holes don’t always break out clean but it is in the correct place, if a single hot it is ok to tie the neutrals but if 2 hots it is not.
    – Ed Beal
    Jul 30, 2022 at 15:19

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