Confusion on Fixture WIring Help

Question

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

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!

Answer 1

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.

Answer 2

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.