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I have two white wires, two black wires, two bare wires and a red wire coming from junction box. My ceiling lamp has one copper wire, one white one black and one green wire.

How do I connect these correctly?

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  • 2
    Can you post photos of the existing wiring please? Jan 18 at 3:14
  • 1
    And the photo of how the old lamp was wired before you removed it.
    – FreeMan
    Jan 18 at 13:45

3 Answers 3

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The simple answer is: The same way the previous lamp was attached.

But if you didn't have a lamp there before, or if you didn't take pictures, then anything is possible. The logical setup is:

  • All black wires = hot
  • Red wire = switched hot
  • All white wires = neutral

The way you can tell for sure is to take a look a the switch. If the switch has one black wire and one red wire (possibly a bare ground wire) then the above setup is true. If the switch is a "smart" switch and has a white wire connected as well as black and red (and possibly also bare) then it is also probably true. Anything else (e.g., black and white connected to switch but not red) and it could be almost anything.

There are two possible setups which will have identical wiring for the lamp:

  • 2-wire cable - power in from panel at light fixture - black (hot)/white (neutral)
  • 3-wire cable from light fixture to switch - black (hot)/white (neutral)/red (switched hot)

and

  • 2-wire cable - power in from panel at switch
  • 3-wire cable from switch to light fixture - black (hot)/white (neutral)/red (switched hot)
  • 2-wire cable - power from light fixture box (but not switched) to another location - black (hot)/white (neutral)

In both of these cases, at the light fixture you wire:

  • All black wires together
  • All white wires together and to the white wire of the light
  • Red wire from switch to black wire of the light
  • All green and bare wires (grounds) together

If you are not really sure about the setup, the safest thing to do is to identify key wires:

  • Turn off the breaker
  • Separate all wires in the light fixture box
  • Turn off the light switch
  • Turn on the breaker
  • Carefully check each wire with a Non-Contact Voltage Tester (NCVT). Exactly one wire should show hot. If more than one shows hot, stop and post pictures and ask for more help.
  • If the wire that showed hot is in a cable with a white wire but not a red wire then that should be the cable from the panel (first scenario listed above)
  • If the wire that showed hot is in a cable with a white wire and a red wire then that should be the cable from the switch. Confirm by turning on the switch - if the red wire is now also hot then you are OK (second scenario listed above), and if not then stop and post pictures and ask for more help.
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  • There is a third possibility: the /2 is incoming power, and the /3 is a loop for two switches (for the option of a ceiling-mounted fan/light combo).
    – nobody
    Jan 18 at 2:57
  • Also a fourth option: power to switch box with two switches, ceiling /3 is neutral and two switches hots (fan and light), /2 goes onward to another fan or light location.
    – nobody
    Jan 18 at 2:58
  • What is the safest way to determine how to wire this ceiling lamp?
    – Yehuda_NYC
    Jan 18 at 3:03
  • With a multi-meter, @Yehuda_NYC, testing pairs of wires in the ceiling and at the switch
    – FreeMan
    Jan 18 at 13:46
  • @nobody I know there are other possibilities I specifically listed the two that have a specific clear fix. Jan 18 at 14:29
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The short answer is, if you need to ask this question, you should consider hiring an electrician, as making a mistake could lead to very dangerous circumstances including electrocution, fire, and death..

That said, all the bare and green wires should be connected together, and the junction box if it's metal should also be bonded to those ground wires if it isn't already through metallic cable (the bare wire from the light fixture may be redundant, often it's used to connect to the mounting bracket. Sometimes this is helpful for helping to hold the light in place while wiring it, but use caution for relying on this to support the weight of the fixture).
Normally all the white wires get connected together as well, including the white from the light, but sometimes a white wire is used in a switch leg rather than as a neutral.

So it really depends on how the switch is wired. If the power comes from the switch, then normally all the white wires should be connected to each other, and the black wire from the switch wired to the black of the light, and all other black wires wired together separate from the light (or if there's another light controlled by the same switch, in this case both black wires should possibly be connected together along with the black from the light. In that case using a pigtail is best practicel.

If there a 'switch loop', then sometimes a white wire is used in a switch leg rather than as a neutral (it's supposed to be marked with black electrical tape in that case, but often it isn't). In that case, one of the wires from the switch gets wired to the black wire on the light, and the other to the black wires in the ceiling box, and the white from the light gets wired to all the remaining white wires.

The red wire could be hot or switched or used for nothing at all. Sometimes an extra wire is installed to allow for a ceiling fan with separate switches for the light and fan.

Bottom line you need to look at the wires coming from the switch (take off the cover plate, remove the switch if necessary, and look), and also use a voltage tester or multimeter to confirm which wires are hot, neutral, and switched, and which if any wires may be feeding another light fixture.
Neutral wires should always have continuity to ground. If there's a switch loop, those two wires should have continuity when the switch is on.

But if you can't confidently identify which wires are which, you should probably call an electrician.

You should always take a photo before removing any light fixture or switch, it helps a lot, so you can just match how it was wired before, which is usually (but not always, correct).

(Edit: the answer by user 'manassehkatz-Moving 2 Codidact' is very good, along with the comments below it, and probably a clearer explanation than mine.. Though as noted in the comments there are multiple possible wiring configurations. I wrote this before reading their comment, and my answer was more for wiring light fixtures in general and not necessarily specific to this installation.)

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If this is original wiring, in other words was installed by an electrician, my best guess is that the red wire in the ceiling is switched for the light that mounts there and the blacks are unswitched and going elsewhere. Like what was already said, a look at the switch would most likely show 2 black wires on one pole and the red on the other switch pole, white wires wirenutted and ground wires wirenutted with a ground connection on the yoke of the switch. If this is the work of a DIY, it could be anything.

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  • Simply repeating someone else's answer with much less detail isn't what we're looking for when it comes to writing a good answer.
    – FreeMan
    Jan 18 at 13:47
  • FreeMan, My answer elaborates on simply looking at the switch and is based on about 50 years of electrical experience. Even with the small amount of information you provided I'm 99% sure what I wrote is 100& correct. You don't appreciate what I wrote because you don't understand it!
    – Rand
    Jan 19 at 11:00
  • That's not the point. You simply repeated what others said with less detail. If you want to show support for an answer, you click the up arrow next to it, you don't write another answer saying the same thing. Please take the tour and read up on how to write a good answer if your unsure of how things work around here.
    – FreeMan
    Jan 19 at 12:17

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