Steel Conduit Question

OK, I have now established proper metal content. The issue is more of an electrical code issue, and I'm hoping the wealth of knowledge of the
usual suspects can help me out.
My basement shop needs more outlets. I had a nice new breaker panel installed a few years back, and it's time to add an outlet so I can run my mill without first unplugging the lathe.
The basement is finished, and has a "half wall" of wooden tongue & groove boards that ends about 10" below the bottom of the breaker panel box. The top of the wall is capped with a piece of 2x molding. The wall is built on 2x3 studs, and the plan is to mount the outlet box in the wall. I can run Romex once I'm in the wall, but I need to get from the breaker box to the top of the wall in a protected (and hopefully tidy) fashion.
My original notion was to bend up 1/2" conduit to bridge the gap. I can drill a hole in the top of the wall large enough to insert an inch or two of conduit. I can attach it to the breaker box with a standard clamp, going in through one of the bottom knockouts. I would then snake the Romex down through the conduit & into the wall.
The question is whether code requires any sort of bushing or clamp on either end of the conduit. Loose wires run in conduit do not require clamps. If the Romex was exposed where it came out of the conduit, a clamp would be required that fits on the end of conduit. It would take a much larger hole to fit the clamp down through the top of the wall, and the Romex is never exposed anywhere.
For my own peace of mind, it would be nice to have a clamp of some sort inside the breaker box to prevent anyone from accidentally yanking the Romex out. One option would be to slip one of the one-way plastic spring loaded NMSC clamps (the sort that usually go in a knockout) onto the cable just where it comes up out of the conduit fitting.
Given that previous licensed electricians ran Romex exposed and unprotected in other areas, I doubt anyone is ever going to get cranky about whatever I do. However, I try to stick to code whenever possible, and I'm at least curious as to exactly what the code might have to say about something like this (if anything). It's a bit too peculiar for any of my wiring books or the course I took years ago.
Thanks!
Doug White
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Doug White wrote:

Yes.
There is a standard conduit fitting that goes on the end of the conduit and provides a NM (Romex) type clamp. You run the NM cable up to the end of the conduit, and strip the NM jacket off for the length that will be in the conduit.
You will need to remover some of that wall paneling so that you can access the interior of the wall at the point where the NM will transition to EMT conduit. You can insert the conduit through a tightly sized hole in the top of the wall, install the NM connector on the end of the conduit from inside the wall, and then feed the wires from the NM up through the conduit, finishing with an inch or two of the NM jacket in the conduit and clamp the NM cable securely at the NM to EMT connector.
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That would work, the catch is that taking the wall apart is a nightmare. Because it is tongeue & groove, it's all interlocked like crazy. I removed a bunch in another part of the basement, and tried to save some for possible future use & repairs. No cigar. I was in a bit more of a rush, but if I could take the wall apart, I'd do the whole run in conduit. Boring an ovesized hole I can slip the clamp down through might be my best bet.
I thought the conduit fitting was only required if the Romex is exposed (that's how I've seen them in the past, but then I didn't think exposing Romex was to code either).
Doug White
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That's just stupid. There's no reason at all to strip the jacket off. There's a common misconception that Romex isn't permitted in conduit. That simply isn't true; in fact, not only is Romex permitted in conduit, the NEC _explicitly requires_ putting it in conduit where necessary to protect it from physical damage. Nowhere does the NEC state, or even suggest, that one should strip the jacket from it.
I can't imagine where ideas like this get started.

Oh, baloney, he doesn't need to do anything of the kind. Unless the location is such that the cable would be subject to physical damage, he's perfectly OK just running the Romex exposed.

So don't do it. Pete doesn't know what he's talking about, and you shouldn't take electrical advice from him. [snip]

If it's required even under that circumstance, it's news to me.

Well, it is: "Type NM cable shall be permitted as follows: (1) for both exposed and concealed work in normally dry locations..." [2005 NEC, Article 334.10(A)] That's not new with the 2005 Code, either. The same language has been in the Code for decades.
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Doug Miller wrote:

NEC Article 358.22 along with Article 334, and Table 1, Chapter 9 seem to suggest that NM would be permitted to be installed in EMT as-is, however there is no reason *not* to strip the jacket after the NM clamp, given that the OP will need to strip the jacket off a foot later anyway inside the load center.

Running the NM (Romex) exposed may be ok if the location can be considered no subject to physical damage, but it is rather ugly. The EMT will look better and can be painted to blend in.

I most certainly know what I'm talking about, and what I posted is the correct way to do the job. I've done many extensive permitted and inspected electrical projects in multiple jurisdictions and have not one had any complaint from the inspectors. Indeed many of the inspectors have commented that my work was among the neatest jobs they had seen.
If the AHJ for your trailer park is ok with your sloppy work and ignores the catch-all "workman like manner" stipulation in the NEC then your garbage is fine for your trailer park.

NEC Article 334.15(B) Protection from physical damage. The cable shall be protected from physical damage where necessary by conduit, electrical metallic tubing...
Whether protection from physical damage is necessary is open to interpretation based on the actual conditions of the installation, so the OP needs to look at the installation and think like an inspector.
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I'll try. I'm assuming that since you're posting from an MIT alumni account, you're in the US; my comments apply to the US NEC only.

Code allows Romex to be either exposed or concealed.

The conduit is not required unless the cable is subject to physical damage.

A plastic bushing is required, yes.

Correct.
I don't think that's correct.

I guess. It's really not necessary, though.

As noted above, that's not a Code violation. Never has been. The Code explicitly permits Romex to be installed either exposed or concealed, and requires conduit only where it's subject to physical damage.

Hope I helped.
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Whether it is necessary or not, I'd put the clamp on and strip the wire off the jacket that is in the conduit, as originally suggested. I had an inspector not like the fact I had the ground wire come out of the conduit with no termination on the end of the conduit. The only thing in the conduit was the ground wire to the water pipe.
I don't like the idea of running machines off of romex, personal choice. If your looking for ease I'd run greenfield (bx without the wire) and then pull the wire through that. They also have conduit to greenfield connectors.
Wayne D.
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Thanks for the input. I thought about running BX, but snaking it through the wall would be a nearly impossible task. It's going to be enough fun doing it with Romex.
These aren't heavy duty machines. The mill & lathe are both 110V single phase, and lesss than 1 HP motors.
Stripping the wire in the conduit has also been mentioned by someone else. Is there any reason it can't be left in the jacket? It's only running ~ 10 inches to get through the conduit, and leaving the jacket on would provide a little extra protection where it comes out into the breaker box.
Doug White
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There's no reason to strip the jacket off, but the EMT shouldn't run straight into the box if you are running romex in it. BTW, with respect to a previous suggestion, Greenfield is not meant to be run in place of conduit, it is for whips running to motors that require flexibility.
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ATP wrote :

And for fishing down existing walls. I ended up rewiring most of a house. Used conduit where I could and greenfield where I couldn't. County ordinance did not allow romex.
Wayne D.
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Is there an exception for that purpose? I know it has been done, but I think you're actually supposed to use a metal jacketed cable assembly. They can be custom ordered for odd conductor combinations.
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ATP wrote:

I believe "Greenfield" is referred to as FMC, Flexible Metal Conduit.
NEC Article 348.10 Uses Permitted. FMC shall be permitted to be used in exposed and concealed locations.
NEC Article 348.12 Uses Not Permitted doesn't list any prohibitions that would appear relevant, only "not where subjected to physical damage".
NEC Article 348.30 Securing and Supporting:     348.30(A) lists exception No. 1: Where FMC is fished. and     348.30(B) Supports. Horizontal runs of flexible metal conduit FMC supported by openings through framing members at intervals not greater than 1.4m (4 1/2 ft) and securely fastened within 300mm (12 in) of termination points shall be permitted.
So it certainly seems that you're permitted to fish "Greenfield" just as you would MC or Romex.
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Thanks. I need to update myself. Apparently it was changed several revisions back. I took my licensing exam under the 1990 code.
http://ecmweb.com/mag/electric_nec_limit_flexible/
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That's just silly. There's no reason at all to strip the jacket off of Romex cable before putting it in conduit. None. Zip. Nada.
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Doug Miller was thinking very hard :

The amount of wire you can put into a conduit is a percentage of the cross-sectional area of the wire to the cross-sectional area of the conduit. That is why you can put more THHN wires into the same size conduit than TW. The jacket and cardboard adds to the percentage. So based on the size of the conduit and romex you could go over the allowed amount. Also 3 wire romex in generally rectangular shaped, while the conduit is round. So once again based on the sizes, you could get binding putting the romex in with the jacket, but it might go in easily without it. I don't have a code book anymore, but I seem to recall the percentage had to do with keeping air space for heat dissipation. Yes I know the wires shouldn't get hot in the first place. The jacket would add an extra layer of heat insulation. Maybe somebody else can tell me if I'm remembering this wrong.
Wayne D.
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What you've stated is correct Wayne. I view Romex jacket in conduit as a sloppy/amateur installation, and probably a good indicator that there are many problems requiring correction nearby.
Conduit isn't for stuffing non-essential material into it.
Romex jacket in conduit indicates to me that someone didn't have the sense or working knowlege to do the job any better, or properly.
I've stripped the jacket and paper off of Romex to make very short runs in conduit (by pulling it out, not slicing the length of the jacket), such as between a panel and a receptacle in a box 12" away, but using jacketed Romex in conduit is a sign of a poorly thought-out installation. The concept of actually pulling jacketed Romex thru conduit is insane.
I've seen complete idiots use SJ multiconductor cord in conduit, and I suppose some folks would defend that too. The idiots for this example chose SJ so they wouldn't have to go fetch spooled wire or bend and couple the conduit sections.. yep, no shit, two straight sections of conduit at 90 degrees, with the exposed SJ completing the "bend". This was in an industrial setting, a steel wire mill (nails, staples etc).
--
WB
.........


"Wayne" < snipped-for-privacy@operamail.com> wrote in message
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snipped-for-privacy@milmac.com (Doug Miller) wrote in wrote:

Yes, thanks! I guess the question is when is it "exposed to physical damage". That's a bit of a squishy call. It's in a coner of the basement, but it could get bashed if someone got really careless. Even if it isn't explicitely required, I'd feel better with it protected by some metal.
Doug White
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wrote:

FWIW, I wired my basement and ran EMT everywhere below the ceiling. I have plastic bushings in the top ends and the bottom ends, of course, are clamped into junction boxes.
The inspector approved. In fact, he was impressed, because I did some really fancy bending with the hickey to get everything lined up perfectly. Whether he was really adhering to code, I don't know.
Oh, where I forgot plastic bushings in a couple of places, I just split them down one side slipped them over the wire and inside of the tube, and turned the splits back against the wall so they couldn't be seen. d8-)
--
Ed Huntress



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wrote:

Sounds like some of the work I did in my old place. I have a collection of CAD drawings where I calculated the angles & dimensions to get the EMT bends just right. That was all going box to box, so I didn't have the issue I've got now. Regular bends weren't too bad. The thing I always hated was doing small offsets to get from a flat surface up & into a box.
Doug White
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wrote:

Yeah, I have around six or seven of those little offsets, and I put more effort into getting them just right than I should have. Nobody ever sees it except me.
--
Ed Huntress



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