I had to replace the light fixture in my bedroom thats on a switch. There is 1 hot wire that powers the bedroom light and also 2 other rooms. after installing the new light i became a bit confused on the wiring and now if i turn the light switch in bedroom off it pops the breaker..Also 1 of the other rooms does not have power anymore. what did i connect wrong? i connected all black to blac and white to white.

  • 3
    Show us the "before" pictures you should have taken of how the wires were connected when it worked. Odds are excellent that all whites were not together, then. "Old style switch loop" probably applied. When you get confused about things electrical, stop and ask for help without just forging ahead, confusedly - that's how problems happen.
    – Ecnerwal
    Commented Mar 14 at 1:24
  • The problem was someone had put a piece of wood in the cieling with a hole drilled in it and 3 sets of wire running through the hole and wires caped with no slack. i wanted to add a proper light fixture box but had to uncap all wires to get them through the small hole
    – Daniel
    Commented Mar 14 at 1:30

1 Answer 1


Based on comments, there are 3 cables. Likely setup is:

  • Incoming power (from panel, possibly by way of other receptacles, lights and switches)
  • Ongoing power (to the rooms that don't have power any more)
  • Switch loop

To fix:

  • Turn off the breaker

  • Disconnect and separate the 3 cables so that no bare wires (except grounds) are touching each other or fixture or box or anything but air

  • Turn on the breaker

  • CAREFULLY use a non-contact tester to determine which cable (and should be just the black wire of that cable, but sometimes there is phantom voltage induced in the matching white wire) has power.

  • Turn off the breaker.

  • Mark the cable you found as the INCOMING POWER cable.

  • Connect ONE of the other black wires to the black wire of the INCOMING POWER cable.

  • Turn on the breaker.

  • Use your non-contact tester to check if the black wire at the switch has power or not. If it has power, mark the cable you found as the SWITCH LOOP cable.

  • Turn off the breaker.

  • If you did not find the SWITCH LOOP cable yet, repeat the same process with the other black wire (disconnecting the first one that you tried - do not connect them all together).

  • If you still did not find the SWITCH LOOP cable, STOP and ask for more help.

  • Assuming you found the SWITCH LOOP cable, mark the last cable as ONGOING POWER:

  • Put a piece of black tape on the SWITCH LOOP white wire.

  • Put a piece of red tape on the SWITCH LOOP black wire.

  • Put a piece of red tape on the light fixture's black wire.

(All taped wires will be referred to from now on as if they were the color of their tape.)

  • Connect all black wires together with a wire nut or Wago connector.

  • Connect all white wires together with a wire nut or Wago connector, including the light fixture's white wire.

  • Connect all red wires together with a wire nut or Wago connector.

  • Connect all bare ground wires together with a wire nut or Wago connector.

  • Turn on the breaker and test.

Make sure you use a good non-contact tester - UL or ETL listed. Something like this Klein from Amazon:

Klein NCVT

  • 1
    thank you so much. will try this
    – Daniel
    Commented Mar 14 at 3:47
  • 1
    it worked just as you said. and i bought the tester you pictured. thank you soo much
    – Daniel
    Commented Mar 14 at 18:27
  • Hurray! To quote "Hannibal" Smith of the A-Team: I love it when a plan comes together! Commented Mar 14 at 18:56
  • 1
    now i just need to figure out why the living room and kitchen outlets have no power. And no i gave not messed with the wiring there..lol
    – Daniel
    Commented Mar 14 at 19:25

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