What is FOUR wire Triplex for?

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A large store downtown has a heavy FOUR wire triplex feeding the building. 3 wires are black insulated, the other is the bare neutral.
The thing that caught my attention to it, is that the 4th wire is not connected to anything. All the triplex I've ever seen is 3 wire, two are insulated, one is bare. That's for a standard 240V single phase system.
Im thinking that this cable was intended to be for three phase wiring. Three hot, and the neutral. Is this right? Maybe that building once had 3 phase service, or they just had that cable on hand when they wired it, and used what they had...
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On 1/13/13 5:57 AM, snipped-for-privacy@home.com wrote:

Triplex to me means three wires, not four. I would call that wire quad. The bare wire would be for the equipment ground, not the neutral. The neutral is current carrying and is supposed to be insulated. There have been some code changes regarding single phase wiring in the U.S. Electric stoves and clothes dryers are what I'm thinking of. It was acceptable long ago to wire them with three wires. The equipment ground and neutral were permitted to be combined. That is no longer permitted in new wiring. The current carrying neutral and the normally non current carrying equipment ground have to be separate.
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On Jan 13, 6:57 am, snipped-for-privacy@home.com wrote:

If it's not connected to anything, why are you identifying it as the neutral? You have 3 wires that are apparently current carrying conductors and one that is bare, not connected. Assuming this is overhead, ie going from the pole to the building, sounds like the bare wire is for support only and you have a 240V service, with two hots, one neutral.
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On Sun, 13 Jan 2013 06:52:52 -0800 (PST), " snipped-for-privacy@optonline.net"

Yep, the bare wire is the support, but it's also the neutral. There are 3 insulated wires wrapped around the bare one, not the usual two. And yea, as another person said, it's not really TRIPLEX, because that would be 3 wires. I'm not sure what they call the 4 conductor stuff, but it's the same type of cable. The way it's connected, it's a 240V feed. So my guess is that either they had 3 phase feeding that store in the past, or else they just used the cable they had on hand when they installed it. It's been there awhile, the building is probably close to 100 years old. I noticed it because there is a deck on the building next door, and I was on the deck last week. The entrance head is probably only 12 feet up from that deck, it's easy to see the unused wire. I tend to notice stuff like that, after doing construction most of my life.
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Your original post is unclear. When you say the 4th wire is not connected to anything, are you referring to the bare wire?
If so, then I gotta repeat the question trader4 asked:
How can it be a neutral if it's not connected to anything? Furthermore, a neutral carries current and therefore must be insulated. How can you call a bare wire not connected to anything a neutral?
If it's not connected it's neither a hot, a neutral or a ground. It's just a wire. If it's bare, then it wouldn't be a neutral even if it was connected to something.
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He just clarified that 4th unconnected wire is one of the insulated conductors. So, like he says, if that is what;s there, then it's apparently a 240V service that might have been 3 phase before.
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On Sun, 13 Jan 2013 16:20:29 -0800 (PST), " snipped-for-privacy@optonline.net"

I would still like to see a picture. If that messenger is truly "not connected to anything" (not bonded) it is a NESC violation and a safety hazard, no lineman would allow to happen.since they are the ones who are in danger,
I bet that when we actually look at it we find it is crimped onto the strand between poles where everything else is bonded. There won't usually be a direct connection to the transformer and maybe that was the confusion.
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On Jan 14, 12:10 am, snipped-for-privacy@aol.com wrote:

In his second post he said that the bare was both the support and the neutral, just as you thought from the beginning. What is not connected is apparently one of the insulated conductors, though even in the new post he doesn't directly say that. But since he said the "4th wire" isn't connected, that's the only possibility left. So it sounds like it could have been a 3 phase that was later converted to 240.

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On Mon, 14 Jan 2013 00:10:46 -0500, snipped-for-privacy@aol.com wrote:

How much clearer can I make this..... One of the insulated wires is NOT connected to anything, (on either end of the cable). It's not taped or capped in any way, it's just there doing nothing. This might be a code violation, I'm not sure, since the wire does nothing. I'd still think it should be capped somehow. But if this is code, I'd think the Po Co would have capped it.
The bare wire IS the neutral and is connected that way. The other 2 insulated wires are connected in the normal manner that any 240V overhead cable would be.
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On Jan 14, 2:16 pm, snipped-for-privacy@home.com wrote:

As far as I can tell, this is the one and only post in which you specifically said "One of the insulated wires is NOT connected to anything". Feel free to correct me if I am wrong.
In your OP you said:
"A large store downtown has a heavy FOUR wire triplex feeding the building. 3 wires are black insulated, the other is the bare neutral. The thing that caught my attention to it, is that the 4th wire is not connected to anything."
Since you mentioned 3 wires, and then the "other one" and then said "the 4th wire is not connected to anything" many of us followed that sequentially and assumed that the "other one" and the "4th" were one and the same. There was no way for us to know that the "4th" was one of the 3 insulated wires.
In your 2nd post you said:
"Yep, the bare wire is the support, but it's also the neutral. There are 3 insulated wires wrapped around the bare one, not the usual two."
Once again, no mention of which of the 4 wires is not connected.
You had the advantage of a visual, all we had were your words, which were not very clear. Had you referred to the "4th wire" as one of the insulated ones, as you did in this post, there would have been absoutely no confusion. e.g. "The thing that caught my attention to it, is that one of the 3 insulated wires is not connected to anything."
In addition, it was not clear to us that the wire was not connected at either end. You said:
"I noticed it because there is a deck on the building next door, and I was on the deck last week. The entrance head is probably only 12 feet up from that deck, it's easy to see the unused wire."
From where we're sitting, all that we can envision is the end you told us about: The entrance head. You never mentioned the other end of the cable until now.
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On Mon, 14 Jan 2013 13:16:34 -0600, snipped-for-privacy@home.com wrote:

I understand the confusion. We have been talking about a bare wire not connected.
What you describe now is a 3 phase drop, connected to a single phase service. My guess is they had 3 phase in an earlier occupancy and switched to single phase.
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On Mon, 14 Jan 2013 13:16:34 -0600, snipped-for-privacy@home.com wrote:

Then you have a 3 phase supply cable repurposed, and the unused insulated conductor SHOULD be grounded at the(preferably) supply end.
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On Mon, 14 Jan 2013 00:10:46 -0500, snipped-for-privacy@aol.com wrote:

And no connection at the building, in all likelihood.
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wrote:

I guess I'm missing where he specifically "clarified that 4th unconnected wire is one of the insulated conductors".
Did I miss a post?
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He made two posts. In the second he said:
"Yep, the bare wire is the support, but it's also the neutral. There are 3 insulated wires wrapped around the bare one, not the usual two. "
If it's the neutral, then it has to be connected. The only remaining possibility is that one of the three insulated conductors is the unconnected 4th wire.
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wrote:

Right, I saw that second post.
We're still taking his word for it that it's the neutral. Even you said: "If it's the neutral, then it has to be connected."
As long as we're still starting our sentences with "If" there's still room for confusion.
I rented a house in the Outer Banks this summer and saw where there were 2 insulated wires and a bare wire coming from the pole. At first it appeared to me that the bare wire was only the support and that there as no ground (which made me curious), but closer investigation showed it to be the ground also. That was the first time I had seen a set up like that.
Where's the picture (or a more detailed description) from the OP that will clarify all this?
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were 2 insulated wires and a bare wire coming from the pole. At first it appeared to me that the bare wire was only the support and that there as no ground (which made me curious), but closer investigation showed it to be the ground also. That was the first time I had seen a

Not sure what the standard is now in North Carolina,but most of the houses I have looked at that seems to be the standard. Two hot wires (insulated) and a bare wire for the neutral that also seems to be the support line.
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He also said that the way it's connected, ie with one of the 4 wires unconnected, it looks like a 240V service. With a 240V service, you have two hots and a neutral, all of which are connected. Yes, he didn't come right out and say that it's one of the insulated conductors that is unconnected, but it's the only interpretation that makes sense.

That is the classic case. It's how alll the overhead services I've seen are done. They use the base wire as both support and neutral.

About 80% of this thread would have been eliminated if the description would have been clearer. How hard is it to just say "One of the 3 insulated conductors is not connected."
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On 1/14/2013 11:35 AM, snipped-for-privacy@optonline.net wrote:

What really confused everything is even though it the the description was ambiguous you ran with the "unconnected neutral" and started defending your position. Then later it became the OPs fault that you did that. I suppose thats what personal responsibility means.

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I suppose you're an asshole too. Everyone here agrees that the post was unclear not only from the start, but even after the second post. I happened to have one interpretation and for that I'm supposed to take "personal responsibility"? Are you for real?
The poster finally clarified it, but even that isn't enough to make you happy.
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