UF Cable

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  #1  
Old 05-18-05, 07:57 PM
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UF Cable

Is it permissible to run UF wire through PVC conduit? The conduit is being used to protect the wire from the coarse gravel it will be running through.
 
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Old 05-19-05, 05:39 AM
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lamartin1965,

If the piping is for protection of the wire itself you are fine to sleeve it in the PVC. Generally you have wandered on a area of the code of debate in that NM should not be in PVC unless it is for protection purposes only as the same for PVC but because of the increased verbadge of protection against physical damage you are fine as long as the entire run from point A to point B is not in pipe...only the part needing protection because UF is designed to be direct bury.....so if you were doing the entire run in PVC and then running UF inside it...do not do it besides it would be hard to get the UF in the entire line....as it would be easier to just run single conductors in the PVC.( if it is a complete run only from point A to point B )....but I digress...if you are running from point A to point B and only the part across the gravel area is going to be in PVC pipe then you are fine.......
 
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Old 05-19-05, 12:16 PM
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ElectricMan:

What is your opinion about this, which would involve NM in PVC for reasons other than protection of the PVC? I am currently designing a house to be built in a few years. In order to make the house readily adaptable to changes in wiring of any kind, be it power, data, or anything else, I plan to pre-install during construction a number of mostly vertical runs of PVC between upper floor rooms and mostly basement end points. The idea is that these would be easier to run new wires and cables in than trying to fish them through holes in studs, and to avoid tearing out any walls. This would also be done on the locations where initial wiring would be placed so that if changes need to be made, it will be equally easy. But in principle, the PVC is being designated as part of the physical structure much like a pre-drilled hole would be, but designed to make things a lot easier. A typical room might have 3 times as many empty ones ready to use as initially put into use during construction.

I don't think heat would be an issue, since running THHN through would not be. But because horizontal portions of the run would not be in PVC, and the fact that I insist on not having splices anywhere, THHN is not really an option, so it would have to be NM. I would be using larger PVC, at least 1.5 inch inside diameter. What other reasons (besides confusing wording in the code) would there be to not run NM in PVC it easily fits in (inside where NM can otherwise be run anyway).

So basically it would look like this. NM would leave the branch panel and run horizontally in the ceiling lattice over to where the PVC comes down. The PVC would have protection on its edge to prevent any cable damage and can have any other means to stablize the cable from moving if needed. The NM would then bend to enter the PVC and travel vertically to the desired level. In most of them, this will be the final location with a box at the end of the PVC.
 
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Old 05-20-05, 10:06 AM
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Skapare,

Well since you are asking for an opinion I shall voice one...lol....personally if the pipe is not a continuous run then I would consider it protection in my opinion and since you are talking to fish it for future expansion I honestly do not have a problem with it because we commonly do this from the basement ( panel location ) to the attic with 2 inch all the time in our area to get wiring to the attic area if needed later.

No my opinion it is protection...well at least thats what I go with..lol...but as long as it is not the entire run I do not see a problem with it personally and the heat is not as big of an issue to me...I have seen some electricians bundle as many as 30 feeds together in a tie wrap.....so if you are only talking about a 2-4 NM of normal size 14-2 and 12-2 then you should be fine in MY opinion....which again is only MY opinion..

Now let the debate over PVC and NM begin...lol
 
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Old 05-20-05, 12:40 PM
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If you call it protecton, I guess that's fine. It does have that effect. For example, a nail driven into a wall is going to hit the PVC (and thus substantial resistance) before it hits the wire. An it can help stabilize the wire in later upgrades since attaching it to the studs inside the wall isn't an option w/o tearing open the walls.

As for cable ties, I'm definitely not going to be doing that. I don't know what you call these, but I've seen these nylon clamps that wrap around the wire not tight, but just enough to hold it steady, with a nail/screw hole on one side. That looks like it should work fine for a single cable down in the basement where it open cables would be running in the ceiling. Some other people have referenced some interesting looking gadgets for stacking a few cables with spacing for where things do get tight near the panel. Th panels will actually be on the first floor, not in the basement. But most of the branch circuits will run down into the basement first (multiple PVCs there to get it spread out as soon as possible). My current floor plan has the electrical room near the kitchen, so those circuits will probably just run straight horizontal over to there (there being no intervening doors along the way since it is the wall next to the roof edge of an A-frame design). The basement will have a criss-cross lattice, so the wiring there can easily go in any direction without being near the bottom edge where a ceiling might go. The rooms directly above the electrical room can also have a direct path, but everything else would be going down to the basement, then back up at the target wall. At some point I'll build this in 3-D virtual reality and see what it looks like.
 
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Old 05-20-05, 01:17 PM
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Correct me if I wrong, but I was always told that PVC could not be used as a wiring method within residential because the fumes were toxic if exposed to fire.

Personally I have never seen it installed so I always assumed this was the case.
 
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Old 05-20-05, 01:31 PM
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Originally Posted by up-n-running
Correct me if I wrong, but I was always told that PVC could not be used as a wiring method within residential because the fumes were toxic if exposed to fire.

Personally I have never seen it installed so I always assumed this was the case.
This is an old wives tale. Now there may be local requirements to this effect, but this is not in any national codes that I have ever heard of. PVC is used quite commonly.
 
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Old 05-20-05, 01:52 PM
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Originally Posted by Skapare
But most of the branch circuits will run down into the basement first (multiple PVCs there to get it spread out as soon as possible).
Skapare, if I am reading this correctly, you are planning multiple RNC's stubbed from the bottom of the panel on the first floor, down to the basement for your NM home runs. If that is the case, you might want to have a look at 312.5(C), no can do.
 
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Old 05-20-05, 08:00 PM
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In the electrical room, it doesn't not actually have to be PVC all the way to the panel. The PVC will be the hole in the floor in lieu of the rougher edges of freshly drilled wood. For protection, all the cables can be protected in front by a clear flat PVC sheet placed over the studs as if it were a wall.

Ironically, it seems this rule could require a less safe installation than what I have in mind. What do you suggest?
 
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Old 05-21-05, 05:58 AM
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Skapare,

I guess we could analize it until we are all BLUE in the face but as RAC stated and I also....we have been doing it for years and it is common for later runs and is protection either way someone slices it and falls into the grey area......and accepted.

As for fumes someone stated..I think RAC answered that one as it is amazing how tales will be told over time...lol

In your case the circuit is NOT complete from the panel to the end product, simply a SAFE method to get wiring between floors.

In my opinion in fishing wire at a later date without the pipe you risk nicking wires, causing jacket degrading and so on which is part of the reason we do add these " Chases " sometimes for later expansion.

Agree with it or not I think I could fight any AHJ on the need for it to protect the wires between floors at a later date.

Now, if your intent is to LOAD the pipe up then NO do not do it...if you are talking about like I stated 2-4 cables at a later date in something the size of a 1 1/2" or 2" PVC pipe...I say fine.......but intent is a BIG part of this....only YOU know the future intent.

P.S. I have a 2" PVC in my wall...lol.......feeding my attic and we do it in all our homes for issues we have not even thought of yet....maybe speaker wires for central stereo, a future flood light..who knows....but I also have alot of pipe in my plumbing also....and I am not going crazy from the fumes of the PVC in my house...lol...or the clients we have done...thehehehe
 
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Old 05-21-05, 01:15 PM
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I don't think the PVC is an electrical issue unless and until I put wiring in it. There may be other residential building code issues, but cutting holes and sticking plastic tubes in them for no apparently reason just isn't in the scope of the electrical code. As soon as I try to stuff a wire down that tube, then, of course, it is an electrical code issue. But unless I am missing something, stuffing it in PVC that is listed for use with electrical wiring, and the conduit is large enough for the cable (I'd think a 2 inch PVC would be plenty for the largest single cable I'd expect to be trivially adding: NM or UF 10/3), why would an AHJ say "no, drill a few holes and jam the wire through there instead"?

If it was metallic, there would obviously be some different issues, particularly grounding (I'd have to stick a box where the conduit ends, splice the cable, and be sure the box and conduit are connected to the ground pigtail). So I'll just avoid metallic except for special cases.

I think I should start a fresh thread since this isn't the original topic.
 
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