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    24vdc long distance

    Any ideas how to or what to do with a antique chandelier that has 22 sockets that needs to be converted to low voltage per electrical inspector or we have to rewire chandelier. The inspector wants us to rewire because the old fixture wire is only rated for 60 degrees. It would be a daunting task to do this.

    There is no access to a attic or basement/crawl space as the building is finished and is historical and we can't do to much to upset building finishes. We are thinking about 24vdc or 24ac
    We found some bulbs that supposedly can be used with AC or DC for e26 base. They are not very good quality and are length is roughly 80ft from switch to light fixture.

    Sent from my SM-G960U using Tapatalk


    #2
    Years ago, I accepted the job of converting a gas lamp on a neighborhood wall to electrical. There was low-voltage lighting around the plants, so I found a 12v Edison-based bulb (automotive trouble-shooting light bulb) and fed a single conductor through the copper tube, using the tube as the second conductor.

    Maybe you can do the same, if there's a concern that the wiring is too thin, and parallel the two wires into a single larger wire.

    Doesn't the temperature apply to the house wiring, not the fixture?
    Master Electrician
    Electrical Contractor
    Richmond, VA

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      #3
      Originally posted by LarryFine View Post
      Years ago, I accepted the job of converting a gas lamp on a neighborhood wall to electrical. There was low-voltage lighting around the plants, so I found a 12v Edison-based bulb (automotive trouble-shooting light bulb) and fed a single conductor through the copper tube, using the tube as the second conductor.

      Maybe you can do the same, if there's a concern that the wiring is too thin, and parallel the two wires into a single larger wire.

      Doesn't the temperature apply to the house wiring, not the fixture?
      I think your right, and the supply conductors would and should only apply to a surface mount fixture not a chandelier or pendant fixture.

      Sent from my SM-G960U using Tapatalk

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        #4
        Originally posted by Ohms law View Post
        Any ideas how to or what to do with a antique chandelier that has 22 sockets that needs to be converted to low voltage per electrical inspector or we have to rewire chandelier. The inspector wants us to rewire because the old fixture wire is only rated for 60 degrees. It would be a daunting task to do this.

        There is no access to a attic or basement/crawl space as the building is finished and is historical and we can't do to much to upset building finishes. We are thinking about 24vdc or 24ac
        We found some bulbs that supposedly can be used with AC or DC for e26 base. They are not very good quality and are length is roughly 80ft from switch to light fixture.

        Sent from my SM-G960U using Tapatalk
        You will want to find LED replacements for the existing lamps. Incandescent at a commensurate wattage at 24V will draw too much current and the wiring most likely won't be large enough. Depending on your needed wattage, look at the Mean Well HLG -series power supplies.

        HLG-320H-24A (320W @ 24VDC)
        https://power.sager.com/hlg-320h-24a-2525463.html

        HLG-600H-24A (600W @ 24VDC)
        https://power.sager.com/hlg-600h-24a-3991236.html

        The "A" in the part number means the voltage is adjustable, so you can goose the output up slightly to compensate for voltage drop if you need to. I use these power supplies by the pallet-load - they've been very reliable. In your case, mount the power supply with a 4" sq. box on either side, and whip the tails into the boxes, one for line voltage and one for low voltage.



        SceneryDriver

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          #5
          Originally posted by Ohms law View Post
          Any ideas how to or what to do with a antique chandelier that has 22 sockets that needs to be converted to low voltage per electrical inspector or we have to rewire chandelier. The inspector wants us to rewire because the old fixture wire is only rated for 60 degrees. It would be a daunting task to do this.

          There is no access to a attic or basement/crawl space as the building is finished and is historical and we can't do to much to upset building finishes. We are thinking about 24vdc or 24ac
          We found some bulbs that supposedly can be used with AC or DC for e26 base. They are not very good quality and are length is roughly 80ft from switch to light fixture.

          Sent from my SM-G960U using Tapatalk
          I think the inspector needs some education. For starters, just making a light fixture "low voltage" does not magically make it safer. In addition if it exceeds the class 2 limit it would have to comply with Chapter 3 wiring methods.
          A little math-assume each of the 22 lamps is 25 watts. 550 watts total. At 24 volt that will be 23 amps. Lots a luck.
          In addition there is the requirement that light fixtures be listed.

          Comment


            #6
            Originally posted by texie View Post

            I think the inspector needs some education. For starters, just making a light fixture "low voltage" does not magically make it safer. In addition if it exceeds the class 2 limit it would have to comply with Chapter 3 wiring methods.
            A little math-assume each of the 22 lamps is 25 watts. 550 watts total. At 24 volt that will be 23 amps. Lots a luck.
            In addition there is the requirement that light fixtures be listed.
            I find it hilarious that he would be ok with changing the ul listing but if I brought that up he would probably say, "Well, I guess I wont do you any favors."

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              #7
              Is this fixture existing (already installed)? How does he know that the fixture is wired with 60 deg C wiring? And if it is, what's the problem with that? What's the wattage of the bulbs you are using?

              -Hal
              Last edited by hbiss; 10-08-19, 01:37 AM.

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                #8
                I feel like an idiot, I miss understood my co-worker he is said that the building wiring to the existing fixture is a cloth type.

                My new questions is is it relevant if it's a chandelier or a surface mount fixture where there is heat trapped in the surface mount fixture opposed to a chandelier where it's just a wire connection and no heat at the junction box.

                Sent from my SM-G960U using Tapatalk

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                  #9
                  Turn the old box up if it is accessible from the attic. Take a new NM cable from it down to the new box.
                  Tom
                  TBLO

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                    #10
                    Its plaster lath and there is no access to the attic.

                    When reading 410.21 I dont see a problem with 60c rated wire since it's a chandelier and there would be no extra heat as from a surface mount fixture. Is this a accurate statement?

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                      #11
                      I think the inspector's way off base here. If there's a concern about the wiring temperature, reducing the voltage (and increasing the current) doesn't seem like a solution.
                      (don't tell him I said that)

                      In my experience, old wiring is usually varnished cloth over natural rubber. The rubber is hard & brittle and crumbles to dust if disturbed, but still provides good insulation performance except at the terminations, which are usually covered with a thousand layers of friction tape.

                      However daunting, rewiring with modern TFFN might be the best approach. It'll satisfy the inspector and be good for another hundred years.

                      Can you persuade the inspector that reducing the current (with halogen or LED bulbs) will reduce the wiring's actual temperature rise, and reduce the need for high-temperature-rated wire?

                      Is the building on the registry? You might persuade the historical-buildings commission to persuade the inspector to grant an exception.

                      Have you considered a harm-reduction approach, such as installing a fast-acting current-limiting fuse?

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                        #12
                        Originally posted by drcampbell View Post
                        Have you considered a harm-reduction approach, such as installing a fast-acting current-limiting fuse?
                        Especially useful if the supplementary fuse protection can be sized at the minimum required to reliably handle the actual lighting load.

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                          #13
                          That's a great idea! I will bring it up. Thanks!

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                            #14
                            If the inspector wants 24 volts, I would humour them.
                            A wide range of 24 volt LED lamps are available, and will draw no more current than 120 volt lamps of similar light output.https://www.12vmonster.com/products/...v-battery-lamp
                            Link to one supplier. These lamps are multi voltage. Many other types exist.

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                              #15
                              Originally posted by Ohms law View Post
                              I feel like an idiot, I miss understood my co-worker he is said that the building wiring to the existing fixture is a cloth type.
                              So the inspector was talking about the building wiring in the ceiling box, not the chandelier itself? What condition is that wiring in? Vintage R or RH wiring actually should be in good condition today given that it wasn't in a location where it was overheated. And I suspect that wouldn't be a problem in the canopy of a chandelier. So right there I would take exception with the inspector since it's not likely that the temperature of 60 deg C wiring would ever be exceeded in this instance.

                              I find that the RH conductors used in AC cable manufactured just before the transition to TW is the most problematic. That's the stuff where you just look at it and it crumbles. Didn't matter if it was exposed to high temperatures or not.

                              -Hal

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