I am making wood lamps for sale. The lamps will not be UL listed, but I am using UL listed parts and want to use best practices.

The entire lamps is made of wood including the base. I took apart a mass produced, UL listed, wood lamp and found all the wires enclosed in a metal box as shown in this photo

Lamp box

My question is does the box I use need to be made out of metal, or is plastic ok? When making a lot of these, drilling holes in plastic is much faster. thanks for your advice. Dan

  • Isn't the box in the example photo you show "structural"? It looks to me like it has a nut, which probably holds a stud attached to the upward post of the lamp. If you're following that design, I would think metal would be best. Sep 16 '20 at 13:52
  • I am not sure if it is structural, but my lamps don't need metal for the structure. Here is a photo of how I did it before I realized I needed a box: photos.app.goo.gl/qfRSq6uBJmPoAvE99 Sep 16 '20 at 13:58
  • I hate to be a sore head but this isn't about home improvement. Try posting this on the arts and crafts site.
    – JACK
    Sep 16 '20 at 13:59
  • I would use caution, the reason electrical products sold in most countries stores are listed is to prevent lawsuits. This is why brick and mortar stores in the US only carry listed equipment. Even if you use listed components of some thing fails in the fixture you could be liable.
    – Ed Beal
    Sep 16 '20 at 14:05
  • Jack, thanks for the tip. I apologize, I saw a similar question on this forum so I thought this was the right place. I will post there next time. Sep 16 '20 at 14:19

I would say that appliances fall into two classes, I and II. Easiest way to identify that is by looking at the power cord to see if it has a ground connection or not. In your case, you could either enclose everything in a metal box, then ground the box (for class I), or you can use a plastic box thus providing an additional layer of insulation to your appliance. Class II devices are called double insulated (from the mains to the user), they don't use a protective earth connection for basic safety. You being the designer could choose either class, just make sure you follow the rules for insulating or grounding. Remember, at the end of the day, it's really all about risk management. And you wouldn't be here asking the question if you didn't care, so kudos to you for that!! Happy lamp building.

  • Please excuse the naivete, but the cord I am using just has a red and a black. So that is just neutral and hot, right? No ground. I don't know what a "protective earth connection" means, but you are saying then that I don't need any enclosure? Or I should use plastic? Sep 16 '20 at 14:55
  • The point of the answer is to say: If your lamp has ANY metal parts that could be touched by the user (so the filament inside the bulb doesn't count, for example), it would fall into the first class, and REQUIRE a ground wire & all the metal parts to be bonded to that ground wire. If you are set on the cord without ground (it would usually be bare copper or green), you must use a plastic enclosure for the connections, and also can't have other metal parts that could become energized if something fails. Sep 16 '20 at 15:39
  • "I would say..." Is there some section of the NEC or some other governing/regulatory body that backs you up? If so, some references would be helpful. Otherwise you're "just a guy on the internet", and while you may be well intentioned, that's not that much to go on.
    – FreeMan
    Sep 16 '20 at 16:20

Thanks again everyone for the feedback. I just had a long online conversation w/a licensed electrician. I showed him this photo of my current lamps - https://photos.app.goo.gl/Xt7FJ8uXp9g1cwi26 The short answer is that he believes that the way it is now is perfectly safe. He also looked at all the electrical codes he could find and there was nothing about needing a box in lamps. That said, the writers of those codes might not have been thinking about spliced wire pressed against wood. I think that even if it's safe, to allay any concerns, I should put the wire in a box and it sounds like plastic is fine.

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