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So, I recently attempted to install a new light fixture to old wiring with no success. I have no electrical experience, so forgive me if this situation and the following questions are either stupid or redundant.

The old -- three light -- fixture included three black wires, three white wires, a red wire and a blue wire. It was replaced with a new fixture using just one black, one white, and one neutral wire.

I connected the new fixrure's single hot and neutral wires to one black and one white wire respectively. As the old wiring included no recognisable ground wire, I simple attached the new fixture's copper wire to the green grounding screw on the new mounting fixture.

The light does not come on when I turn the switch.

Do I need to connect all existing black and white wires to the corresponding single black and single white wire on the new fixture? Should the red and blue wires be attached to anything else or left unconnected and capped? Is it normal that there appears to be no ground wire included in the old existing wiring?

To answer ThreePhaseEel,

enter image description here

  • Can you post a photo looking up into the junction box where the old fixture was attached? – ThreePhaseEel Jan 9 at 2:40
  • Remove that white wire from the ground screw NOW. You need to know that green wires, green/yellow wires, bare wires and metal conduit/boxes are always and only safety ground, are usually connected to each other, and never connected to any other kind of wire. This would have electrified your lamp. I am glad you are asking for help. – Harper Jan 10 at 18:51
  • I didn't think it looked like a good idea. It's been removed. – Auld Finger Jan 10 at 19:30
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You hook the new lamp exactly the way you found the old lamp

All the white wires from the old lamp went to one place. That place is where the white wire goes for the new lamp.

All the black, red and/or blue wires from the old lamp went to one place. That is where the new lamp's black wire goes.

You don't mess with anything else.

Particularly, you do not group wires by color code if they weren't before. Color codes do not have the purpose you wish they did, they don't tell which wires go together or what the wires do. Cable colors are part of manufacturing the multi-wire cables, because making all the wires the same color wouldn't work.

When you see wires bundled together, those wires are not "spares". They are already engaged in other tasks and need to stay the way you found them.

  • If both blue and red wires went only to different wires on the old lamp, then pick one and cap the other.
  • It's not unusual for there to be no grounding wire in old fixtures. Don't "island" a ground by attaching it to something, what you did was fine.

Oh. You messed with anything else.

Well, the good news is, given the blue wire and combinations you stated in your comment, this work is plainly in conduit, so there's a fair chance the wire colors are in fact meaningful. What a refreshing change, Usually they don't mean much.

The ground will automatically get picked up via the mounting screws when you mount up the harp. (This "via the screw" method only works on lamps and switches, not receptacles). So grounds are no worry, I love metal conduit.

The whites look OK, with one remotely possible, critical exception.

Based on what you say it's the blue wire. They were kind enough to color code the wires and it looks like blue, being a solo, is for this light.

You could also try the red, but Ihave a feeling that's for the fan.

Beyond that you are going to need to bring in a pro. Do not just repeatedly experiment. You are likely to discover combinations which do what you want, but that create a dangerous situation.

  • Thanks for your advice. I've managed to get the light to come on, but it doesn't turn off at the wall switch. On it iff, the light stays on. I've tried a combination of things and nothing is working. Sidenote: there was also an additional short white wire that was in with the old fixture, but I can't recall how/where it was being used. I should have taken a picture for reference before removing the old fixture, but that ship has sailed now. !enter image description here!enter image description here – Auld Finger Jan 10 at 18:37
  • Is that your closest recollection of how it was hooked up? Or are you just spitballing at this point? In particular, did you connect the wires from the ceiling because they were like that before, or did you just match color to color? – Harper Jan 10 at 18:46
  • In all honesty, I don't remember. The old light attachment had three lights which were wired to each black wire. I want to say that the small, additional, white wire was used to connect the fixtures three whites to the ceiling whites. If it helps, the ceiling set up consists of four separate wired holes which are: black/white -- black/white/red -- black/white/blue -- white/red. – Auld Finger Jan 10 at 19:22
  • Is a second light fixture also controlled by this switch? What you saw before was the whites being pigtailed, since there were already 4 whites and adding 3 lamp whites (for 7 total) was too many. – Harper Jan 10 at 20:34
  • There is a fan fixture with lighting that is controlled by a separate switch that makes up a two-switch unit -- one switch for the fan/lighting; one switch for the light we're talking about. I tried adding the blue wire to the whites but this tripped the mains switch so I unattached and capped it. I've disconnected the fixture's hot wire for now so the light doesn't remain on constantly. – Auld Finger Jan 10 at 20:58

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