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I'm replacing an old fixture into a new light fixture and ran into an issue where it does not respond to position of the wall switch.

There are two pairs of wires coming from the wall into the socket. One pair is always on (voltmeter shows 120V) and one pair is always off, regardless of the switch position. Measurement between white from one pair and black from another pair shows fluctuating result around 60V.

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I did not record how the old fixture was wired, but I vaguely recall that either two black wires or two white wires were connected and this struck me as odd.

Why is it wired like this? Is this a case of bad wiring? How do I correctly wire up the light so that it can be controlled by the switch?

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  • How did you control the old light fixture? Did the wall switch ever do anything? Is it possible that the old light fixture had a pull cord to control it? Commented Jun 25, 2021 at 20:35
  • Are there 2 lights? Commented Jun 25, 2021 at 20:38
  • The old fixture was a fan and light combo with pull cords, but it was ultimately controlled by a single switch. Commented Jun 25, 2021 at 23:10

1 Answer 1

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Assuming that the switch is intended to control the fixture:

The “always off” pair is actually your switch loop, connected to the switch.

You want to connect the “always on” black (hot source) to the “always off” white (that’s right). The remaining black is the switched hot to the fixture and the remaining white is the neutral return from the fixture.

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    And the white should be re-marked at both ends (I prefer red tape, it's more obviously a marking than black tape to the uninitiated - I hope, anyway. Nothing is foolproof, they always make better fools.)
    – Ecnerwal
    Commented Jun 26, 2021 at 2:17
  • Thank you for using approachable lingo! This didn't work; Why not connect white from source to the white from the switch loop, and the fixture between the two blacks? Or fixture between two whites, and connect the black wires? Commented Jun 26, 2021 at 2:44
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    because the electrical code says not to do that. The reason is possibly because doing it in the suggested way an experienced person can tell which wire is which just by looking at how they interconnect. if you connect black to black it's not clear which is the supply and which the switch. if you connect white to white the switch is in the neutral and that's unsafe.
    – Jasen
    Commented Jun 26, 2021 at 3:41
  • @AmadeuszWieczorek You say this didn't work. What happened when you tried? Was the light still always on? Was the light never on? What?
    – DoxyLover
    Commented Jun 26, 2021 at 6:45
  • @DoxyLover I re-read your advice and realized I misunderstood it and wired fixture incorrectly. Your advice was spot on - thank you! Ecnerwal I marked the wire with red tape for posterity - if I earlier saw the tape I would have likely not ran into this issue. Commented Jun 26, 2021 at 21:48

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