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I'm trying to hook up a new light fixture and when I removed the old one, what I saw confused me.

Fixture Wiring

The taped wire on the far left seems to be coming from the switch, I've tested with a voltage reader by turning on and off the power and testing from a distance with a wooden yard stick.

The bundle of black wires second from the left was within the box already when I took the old fixture off.

The remaining two wires are seemingly a neutral on the far right with the yellow cap (no voltage with power), and a hot that's constantly on.

When I first hooked up the fixture, I could power the fixture from the switch, and it seemingly worked fine. I had only hooked up the switch wire to the black from the fixture and capped off the remaining hot thinking it was from a fan the previous owners might have had. I then noticed that two rooms did not have power, realizing that the remaining hot needed to be hooked up, somehow.

I've tried seemingly every combination I can think of, even tripping the breaker at one point due to I think a live and neutral being capped together.

A couple of observations I've made:

  1. If I connect the fixture black to the continuously hot black, the lights flicker, and the upstream rooms also flicker on and off, and the light switch doesn't work
  2. If I connect the fixture black to the switch black, the light no longer turns on and off from the switch and nothing is on downstream from the fixture. Note: I can still turn the switch on and off and read voltage through my jury rig that is extremely dangerous I'm sure.
  3. If I connect all three live wires together (fixture black, box continuous hot, and switch hot), it's similar to #1

My questions are:

  • What are these bundles of three random black wires?
  • Did the circuit tripping end up short circuiting the switch, and that's why everything else is no longer working?

Thanks!

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    STOP TRYING COMBINATIONS. Look. Obviously your algorithm is to try combinations until one works, then call it good and done. With electrical, many combinations will seem to work that will kill you. If you don't know why you're doing it, don't do it. – Harper - Reinstate Monica Nov 22 '19 at 6:35
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    Do you have outlets anywhere that are dead now? Or lights that don't work? Unplug EVERY load and turn off EVERY light. See if that red-capped white wire stops indicating hot. Are you saying the left white wire is either hot or not, depending if the switch is on? – Harper - Reinstate Monica Nov 22 '19 at 6:46
  • Yes the left wire is either hot or not depending on whether the switch is on. – dardo Nov 22 '19 at 11:40
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I don't have enough reputation points to comment under where you replied to Harper that the left white wire is hot or not (switched).

You've got a switch loop wired there. Basically, the power comes to the fixture first rather than the switch. As a result, your black switch wire is bundled with the other hots and carries power down to one leg of the switch. Then, the white wire you see at the left connects to the other leg of the switch and carries that power back up to the light fixture. The black tape on the white wire indicates that it's hot.

It's hard to see with the shadows, but I think I see 3 black wires bundled there. So, one of those is your hot from upstream on the circuit, one is the switch wire, and the other is what's carrying power to everything downstream on the circuit.

The whites at the right should both be neutrals, those will be pigtailed with the neutral side of the light fixture.

This is a pretty standard fare.

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  • To be clear, I was the one who put electrical tape on the wire after hours of walking up and down stairs flipping the breaker. That was the wire that turned on and off when I'd flip the switch. – dardo Nov 22 '19 at 15:21
  • Question for you, would the neutrals on the right be carrying voltage? – dardo Nov 22 '19 at 16:20
  • Oh, well the trade standard is to mark white hot wires that way, so good job lol. This is very simple to re-connect your light fixture. Shut the power off at the breaker, twist the two white wires on the right together and then connect them to the neutral (white) wire on the new fixture. Don't touch the black wires, they are fine the way they are. Wire the white with black tape to the hot (black) side of the light fixture. Done. – clwhoops44 Nov 22 '19 at 18:18
  • Turns out I had the wiring correct, apparently the dimmer switch was bad, and was throwing all my logic and reason out the window! Oh well, electrician came and fixed it all up, we can shower with the lights on again. – dardo Nov 22 '19 at 20:58
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OK, after turning off the breaker, take the two white wires on the right, with the orange and the yellow wire nuts, and twist them together. Turn the power back on and check the other rooms for power. If they have it, get your voltage meter and check between the ones you just twisted together and the white wire with the tape coming from the switch. If you get some on/off readings while operating the switch, then turn off the power again and hook the black wire from the fixture to the white taped wire from the switch and the white wire from the fixture to the two you twisted together. Turn back on the power and text everything. Turn off the power again, tuck the wires back into the box and screw in the fixture.

FYI, that group of black wires contains the hot from the breaker, the hot to the switch and the hot to the other rooms.

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  • The two wires on the right, the yellow was showing no voltage, and the orange was showing constant voltage. Does that make sense to you at all? – dardo Nov 22 '19 at 16:41
  • What are you using to measure voltage? – Platinum Goose Nov 22 '19 at 16:48
  • Yes it makes total sense.. open neutral. Also, when when stating a wire is hot, mention how you determined that, ie., to ground, to a black wire, etc. – JACK Nov 22 '19 at 16:49
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    @dardo No!! don't touch them. – JACK Nov 22 '19 at 17:12
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    @dardo You shouldn't do anything with the black wires... Follow the answers – JACK Nov 22 '19 at 17:21

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