Hello there.

Just joined to ask for help with my newly purchased used ceiling light.

There are 5 bulbs on the ligh and 3 wires: one red, one blue, one black. 1 build lights up when I hook the red and the blue wires to the house circuit (old house, no ground). 2 bulbs light up when I hook the black wire to the same spot as the red one. The 3 other bulds light up when I hook the black wire to the same spot as the blue one (picture). How do I get all 5 bulbs to light up together?

Thanks for your insight!

  • BigDanishGuy@sh.itjust.works
    0·
    1 year ago

    Alrighty then. I’m not familiar with anything but Danish electrical building codes, so have that in mind when reading the following. In newer Danish installations red would be the switched wire and blue neutral. But that assumes that building codes were followed, sometimes DIY’ers will mess it up and leave you with a potentially dangerous situation.

    I saw the other comment about how you could end up with parts of the lamp being shorted to 230V if you don’t know what you’re doing. I wouldn’t be so afraid any longer, if that happened you would have felt it by now ;-) besides we don’t have a history of connecting anything but protection earth to the metal part of any device, and with lamps that’s only done if it’s designed to be used in a damp environment, like a bathroom or outdoors.

    I suspect that the lamp is wired so that the blue wire is neutral and connected to all the sockets, red and black are connected to 2 and 3 sockets respectively. That would allow you to turn on either 2, 3, or 5 bullbs. But it is just extremely hard to diagnose with text and pictures only.

    If you disconnect and unmount the lamp, and then take a look at the sockets in the lamp. Can you tell which wires goes where?

    Do you have a way of measuring continuity? Like a multimeter?

    Have you tried switching bulbs around? Maybe some are burned out?

    • HenriVolney@sh.itjust.worksOP
      0·
      1 year ago

      Thanks a lot for taking the time to go be me so much information.

      I started with switching the bulbs and that’s all right

      Having no ground wire coming from the ceiling, I am definitely not going to attach any wire to the body of the light.

      I think I will try to attach the blue wire on one side and red and black together on the other side, maybe it will work ?

      I could disassemble the light to inspect which wire goes to which socket but I’m not sure I could put it back together again.

      Anyway, thanks a lot

      • BigDanishGuy@sh.itjust.works
        0·
        1 year ago

        Thanks a lot for taking the time to go be me so much information.

        Don’t mention it. It’s a mental challenge for me to diagnose this problem with only text. And I like a challenge.

        I started with switching the bulbs and that’s all right

        Just to make sure, you have 5 sockets AND 5 known good bulbs? Ie you are sure that all bulbs are working?

        I think I will try to attach the blue wire on one side and red and black together on the other side, maybe it will work ?

        Maybe. I’m fairly certain that the lamp is wired such that

        • one wire is common for all sockets. The common wire is the one you’ll want to connect with the blue wire in the ceiling outlet.
        • the other wires are going to 2 and 3 sockets respectively.

        The question is just, which wire is which?

        I’ve seen black used for neutral in a 1950s installation in DK.

        If you’re up for it, I propose that you test it systematically. We need to figure out which wire need to be separate from the others. Start by enumerating the bulbs.

        I’m going to shorten the names of the wires, lr, lba, and lbu. L for lamp, r for red, ba for black, and bu for blue. Same for ceiling wires, cr and cbu.

        Which bulbs light up when you attach

        • lr and lba to cr and lbu to cbu? (I think you mentioned one bulb in this case? I’m not able to go back and find it while writing the comment in this app.)
        • lr and lbu to cr and lba to cbu?
        • lba and lbu to cr and lr to cbu? (Which you did reversed, but it’s the same, and you said two or three bulbs?)

        I’ll bet that in one of these cases all the bulbs will light up. And that will be the way to wire the lamp up.

        If none of the three combinations lights up all bulbs, then either the lamp is faulty, or my own bulb is :-)

        • HenriVolney@sh.itjust.worksOP
          0·
          1 year ago

          Issue is I can’t see any color for the ceiling wires (only one or two cm of wire, hooked directly into the connector), so I’ll use C1 for ceiling one and C2 for ceiling 2. Lba makes the switch:

          • first picture is Lr+Lba on c1, Lbu on c2, two bulbs lit
          • second picture is Lr on c1, Lba and Lbu on c2, three other bulbs lit.

          I don’t think switching c1 and c2 will make any difference.

          I am wondering if black shouldn’t go to both ceiling wires…

          • BigDanishGuy@sh.itjust.works
            0·
            1 year ago

            Definitely get lba connected to one wire, and lbu and lr to the other. Lba is the common wire, get that alone and all the bulbs will light up.

            Differences between the wires in the ceiling is that one is switched live and the other is neutral.

            It may be pedantic, but lba connects to the side of the sockets, which is more easy to touch. That’s why I would connect that to neutral. But if you can’t see the wires in the ceiling, then it doesn’t matter that much.