I'm installing a simple light fixture in my office. The wall switch has one black and one white wire connected to the switch. The overhead ceiling box has the following 3 connections:

  1. 3 black wires connected
  2. 2 white wires connected
  3. a single white wire.

I connected the black wire from the fixture to the 3 black wires. Then I connected the white wire from the fixture to the single white wire in the ceiling box but the light does not work.

Then I connected the white fixture wire to the two white wires in the ceiling box. The light works but you can't switch it off.

Then I connected the fixture white, to the 2 ceiling white and also connected the single ceiling white but this throws the switch. I don't know what to do next.

Any ideas? I'll try to attach two images.

  • 1
    How was the previous fixture connected? What happens when you wire up the new one in the same way?
    – brhans
    Sep 28, 2020 at 16:30
  • If you cannot get your images added (click edit, then click the "sun & mountain" icon above the text entry box), post them to imgur or similar and paste the links in the comments, someone will edit them in for you.
    – FreeMan
    Sep 28, 2020 at 18:30

1 Answer 1


You've got a switch loop. Forget about the three black wires. Take the white wire from your fixture and connect it to your two white wires that are already grouped together. Take your black wire from the fixture and connect it to the single white wire. Mark that wire with some black electrical tape to show it's a switched hot. Mark the white wire in the switch box with some black tape too.

  • Yup, except that I would warn to wait until you are sure that it works prior to marking the white wire as a switched hot... Sep 28, 2020 at 21:53

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