Old custom conduit light fixture wiring

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  #1  
Old 04-30-20, 09:13 AM
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Old custom conduit light fixture wiring

I have what I believe to be a custom conduit light fixture and I am trying to decide what I should/could do.







There are a total of 20 female connectors welded along this conduit. 10 of them unused and left open. The other 10 are wired with those standard lamp holder fixtures that you will find in exterior flood light fixtures. All of them work except for 2 and all controlled by the same switch. I have five 6w LED bulbs on them right now.

At the end of the conduit it disappeared into the soffit/ceiling.





The conduit is about 3" in OD. I think the entire conduit is considered a junction box. It has a plate welded on the top side to connect to the bottom of every joist.



The past weekend I cut a hole on the wall of the soffit in order to get do some wiring modifications - change out some old 2 wire cloth romex wires to NMb wires.



But once I looked into the opening, I was able to see the end of this conduit. It is open ended, not tied to any junction box.



and what goes inside the conduit looks to be a thin lamp cord?



Is this a problem?

The conduit light was made to match the framing steel members obviously. The connecting plates to each joist had to be welded on, the laborious effort to fish the wire to each hole, this wasn't some DIY weekend warrior project 80 years ago.

If I decide to keep this fixture, do I need to rewire it? Do I need to connect the open end to a box? I assume the other end is the same.
 
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Old 04-30-20, 10:05 AM
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Your fixture is not listed by any testing agency as required.. I don't see where the junction was made to the home's wiring.
 
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Old 04-30-20, 10:11 AM
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It is a bit of a grey area. The entire assy could be considered a light fixture. In that case the lamp cord within it is fine. However the lamp cord should terminate in a normal junction box to regular household wiring.
 
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Old 04-30-20, 11:20 AM
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It is definitely a "custom" installation. Obviously not UL approved and doesn't really fall under the NEC since it's a fixture (in my opinion). I don't see any reason to worry too much about it - it's obviously been working for decades.

- I don't like the small lamp cord running probably 600-1000w when it was incandescent, but now with low-wattage LEDs, I don't see any issue.
- I would somehow add a ground wire to the metal pipe. This will help protect if a splice in the pipe gets loose, and there are probably a lot of splices.

I'm trying to figure out how to mount a standard electrical box to the end of the pipe and ground it. Maybe if a 3" EMT connector would fit, it could then go into a plastic 4x4 or 6x6 box. It would also provide you a threaded mount to the box and the ability to ground the pipe using a ground bushing.

Basically you don't want the lamp cord just hanging in the air like that.
 
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Old 04-30-20, 11:42 AM
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Yes I know this is non-conforming to any code today.

I have junction boxes near by, and I will trace where the lamp code goes to. My guess is it goes to a junction box in the attic, because it's regular romex at the wall switch.

Is it a fire hazard? Presently I am using five 6w LED bulbs, that's 30W total. I cannot imagine back in the days if someone connected all 10 with 75W bulbs, that would melt a dimmer even rated for 600W right?

Once I find the lamp cord's other end, should I replace it from there to where the conduit ends with say a 12-2 romex? and put a junction box as close to the end of the conduit as possible?

Yes it might help to ground the pipe. I can tape a hole on the pipe to attach a ground screw.

Wait, what if I use a step bit to drill a 1/2" KO hole on the top side of the pipe? Debur the edge to make it real smooth. then put a close nipple in, secure on the inside, then mount a 4x4 metal box on it, then thread the lamp cord through the KO hole to the inside? Then splice to romex, cover with a blank cover plate. Would that work?
 
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Old 04-30-20, 11:45 AM
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Ahhhhhhhh....... the mystery continues...... what-kind-wiring-inside-large-conduit.html
 
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Old 04-30-20, 01:03 PM
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I have product design safety experience, but not with residential lamps.

If it were me, I'd make sure all the fixtures are shell's to neutral, and definitely ground that mess.
I would also avoid at all costs connecting zip cord to house wiring with any "permanent" method, including wire nuts. No way, no how to the idea of connecting 18AWG to a home circuit without a human accessible plug/socket.
The devil is in the details; one detail is removing sharp edges INSIDE the conduit ends, everywhere there is a wire.
 
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Old 05-01-20, 06:23 AM
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I assume if there is only one wire going inside this conduit, then this wire is spliced and pigtailed at every place there is a lamp holder with two wire nuts, each connecting three conductors, one from upstream, one from downstream, and one from the lamp holder? What is the likelihood that if I unscrew a lamp holder and attempt to pull it out, that I will be able to pull out that splicing and use it to pull in new conductors such as #14 THHN?
 
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Old 05-01-20, 08:51 AM
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Hi, just curious, are those 1/2 conduit couplings welded to that pipe?
Geo
 
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Old 05-01-20, 09:24 AM
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Yes they are welded to the pipe. Total 20 couplings, 10 on each side. But 10 if them are not connected to anything just empty connectors I can see straight through to the opposite side's coupling.

There are twelve joists, so twelve steel plates also welded to the pipe where it is attached to the joists.
 
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Old 05-01-20, 09:34 AM
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So there are 1/2 couplings into which these fixtures are threaded, where are the splices ?
I cant imagine a wire nut small enough, have you tried removing one of the fixtures?
Geo
 
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Old 05-01-20, 09:34 AM
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If I were to replace the internal wiring, Id probably use MTW16AWG. Stranded, easy to work with. On the splices, I might use the correct WAGO push in connectors, easily found at Orange stores.
 
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Old 05-01-20, 06:43 PM
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I might attempt to rewire it "properly" if I can find a way to use the existing wiring in the conduit to pull new wire in. out.

But that would only work if I can pull the wire nuts inside the conduit out of each coupling, or else as I pull the old wire it may end up pulling loose leave one end in and one end out. I think it will be too challenging to disconnect all the lamp holders and pull the whole wire out, then insert new wire and try to use some sort of cloth hanger hook or dental pick to pull the wires out.
 
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Old 05-02-20, 06:26 AM
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How much work do you want to put into this fixture? Part of me says, it's been working for however long, and you've just helped it along by drastically reducing the draw. (what was probably 600-1000w before is now down to 60w). Plus, in a steel pipe, especially if grounded, there's not a heck of a lot that can go wrong.

I'm not sure you'll be able to pull the wire nuts out through those small 1/2" holes. I mean, they got them in somehow, so in theory you should be able to get them out again. But I don't think using a hook type tool will be hard to pull the new wire out. If that gets too hard, I was thinking you could use a fish tape and some twine as a pull cord, basically fishing from the end each time.
 
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Old 05-02-20, 07:56 AM
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How much work do you want to put into this fixture? Part of me says, it's been working for however long, and you've just helped it along by drastically reducing the draw. (what was probably 600-1000w before is now down to 60w). Plus, in a steel pipe, especially if grounded, there's not a heck of a lot that can go wrong.
well that is the dilemma. Out of the twenty welded couplings on the pipe, ten of them have lamp holders on them. Out of the ten lamp holders, eight of them work. Two lamp holders don't work. I have no idea if it's because the lamp holders went bad, or because somehow the wires inside came loose. So part of it is curiosity and part of it is wondering if there may be a few wire nuts inside that may be loose.

The pipe is not grounded obviously. To ground it, can I tap a 8-32 hole on the outside of the pipe and put a green screw on it and connect a bare copper conductor from that screw to a metal box nearby that is fed from a 12-2 romex on another circuit from the panel?
 
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Old 05-02-20, 08:08 AM
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I traced the wire coming out of the conduit to a junction box about 4' away. There it is spliced to a 12-2 romex cable.

So one question is if I add a new junction box at the pipe, and run the thin cord to that junction box, then replace the 4' of wire in the attic with regular romex to the existing junction box, that should help some right? No way it will ever be legal conforming but while I have the soffit open I like to do what I can.

A new junction box can be mounted on the pipe. I can drill a 1/2" hole on the top side of the pipe, with a step bit. Then use a deburrer to debur the cut edge. Then I can mount a metal box on to the pipe, where my hand can still reach into the pipe and access the 1/2" pole. May be use a close nipple with a a nut on each end? I can then take the existing wire and run it through the mounting hole so none of it is exposed outside of the pipe. From there I connect it to a new piece of romex and run that to the existing box 4' away. By doing so I eliminate the cord being exposed in the attic, and I grounded the pipe. This is not too much work and seems straight forward. Thoughts?
 
 

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