Hot answers tagged

57

Yes, NM cable can be in conduit. In fact. NEC calls for it to be in conduit, when protection from physical damage is required. National Electrical Code 2011 ARTICLE 334 Nonmetallic-Sheathed Cable: Types NM, NMC, and NMS II. Installation 334.15 Exposed Work. In exposed work, except as provided in 300.11(A), cable shall be installed as ...


39

Empty conduit is your best bet here. No point in guessing what (if anything) you may get, and guessing wrong. While you can leave a pull string in it, you can also just vacuum a pull string into it when the time comes (that's what is normally done to install it in the first place). If you do leave a string, don't worry about how big/strong it is: it can be ...


32

Guaranteed Reusability If you run the wire as you are putting together the conduit, there is a possibility, unless you are truly careful about all the details, that you could end up in a situation where your initial set of wires are perfectly fine, but that pulling them out to replace them - or more likely pulling in new wires (out is "easy") will ...


22

The wires in NM aren't labeled for use outside the cable jacket, and may not be the correct type for use in conduit to begin with First off, the wires inside a NM cable are not marked or labeled at all, which automatically makes them unsuitable for use in a conduit wiring method, as NEC 310.120 requires conductor insulation to be marked/labeled with the ...


21

Far more opportunity to damage the wire insulation - either by mechanical damage from the exposed ends of the conduit/fittings being slid along the wires (metal or PVC), or from cement/primer if PVC. An assembled conduit (or duct) will have all the various ends joined (and de-burred to remove any internal sharp edges, if properly assembled.) wires or cables ...


19

Well, it's never a good idea to "divining rod" the intent of the NFPA. Because jackasses mainly are looking for one reason that they can rationalize around, so they can fabricate a reason why the Code doesn't apply to them. Really, they just don't want to follow Code, but they are not honest enough to call themselves outlaws. So, it is a stupid ...


13

The best future proofing you can do is over-provisioning the amount and size of conduit. Pulling a cable through a relatively straight 200m run is not out of the question especially with proper cable lubricant and a large enough conduit. I would suggest not pulling anything like fiber without proper specs on the gear on both ends. There's a good chance ...


11

You can, but it really isn't worth it... It's a nightmare to pull NM (Romex) is already solid wire except in the large sizes, and now you have 3-4 wires bound together. You are trying to pull this around maybe 14" radius elbows, and if the NM gets twists in it (it always does), it really drags in those places. It's just a stiff, miserable pull - enough ...


11

There is a widespread belief that the NEC does not allow NM-cable in conduit, but does allow THHN (the individual wires). This belief is incorrect. However, it is for some reason lesser-known that NM-cable cannot be used in outdoor conduit at all, stripped or otherwise. So, the answer to your question is: stripping is a common but misguided (unnecessary) ...


11

There are collar boxes available that have conduit KO's (knockouts). Just install one on top of the existing device box and run your conduit. This one is even better as it has more volume: Brand: Steel City, Part number:531511234UB Here is a raised device cover to be used with the 4x4 box shown. They can be had in any number of different configurations.


11

You can transition wiring methods at a junction box. Use the EMT wiring method up to the junction box (whole nine yards with fittings and clamps). Then use the NM wiring method beyond it. The junction box must remain accessible without screws, nails or demolition (other than the ones on the junction box lid, of course). If you don't like the aesthetics ...


11

Yes, this is a good idea, but a few details. No more than four cables per conduit, unless you're willing to upsize ALL the cables to the next larger size. That is 310.15(B)(3)(a). The conduit needs to be fairly large, because the cables are oval. Each oval cable is treated like a single wire of the wide dimension (because they twist). They can't fill the ...


11

You discovered wrong. Ethernet runs at 100MHz and up, your line voltage at 60Hz is virtually DC at that frequently difference. With that said, you should still run your data cables in conduit. Not for interference concerns, but so that in 2040 you can easily replace the cat5 with something new for our 20K ultra VR direct brain video or whatever is the deal ...


10

You can run type NM cable in conduit, as long as the conduit is sized appropriately, and is not in a wet or damp location. If you remove the sheath from the conductors inside NM cable, you cannot use the conductors for anything (anything electrical anyway). Type NM cable is rated, listed, and labeled as a cable assembly. The conductors inside are not ...


10

Using the same hand-bending tools you already have, you can approximate a larger bend radius by leaving short sections of straight conduit in between multiple bends. Below is a picture showing the minimum radius bend you currently achieve with your hand tool (picture on top) and then using three segments of bending coupled with two straight lengths to ...


10

Derailed by Derating Your plan is a non-starter, even if you overcome the fill issues you're having, because of the other limit the NEC places on conduit fill; namely, the derating factors found in 310.15(B)(3)(a) that limit ampacity based on the number of current-carrying conductors. The first two rows of the table are normally not an issue because nobody ...


10

You can mark the white or gray neutral wires with colored tape. Unlike marking a switch loop wire in cable (where it changes white from neutral to hot), this does not change the function but is simply an identifier. Real simple: Black + White or Black + White-with-black-tape Red + White-with-red-tape Yellow + White-with-yellow-tape Blue + White-with-blue-...


10

What you're after, traditionally, is a three-piece coupling The fitting you're after to join a pair of rigid conduits where you can't turn one or both conduits is called a three-piece conduit coupling. As its name implies, it consists of three pieces: a doubly-threaded (inside and outside) chase nipple, a female threaded ferrule, and a female threaded hex ...


9

That's a pull point, albeit a possibly miserable one in practice. The latter bit being "informed opinion" as a frequent user of conduit. As such, it "resets" your 360° (practically speaking, try to stay at 270 or less when possible - it meets code and there's less swearing involved.)


9

Only if you pull from there If you're not actually using it to pull... then you can't use it at all. This turn is far too tight to pull around. It will simply tear the wire. If you're actually going to use it to pull... then this not only doesn't count toward your 360, it resets your 360! Say you have ===90 sweep===90 sweep===this thing===90 sweep=== ...


8

In addition to Tester101's excellent answer on when NM-B can be run through conduit, there is a section in the NEC which indirectly prohibits running NM-B through conduit in specific scenarios: From the 2014 NEC: 312.5 Cabinets, Cutout Boxes, and Meter Socket Enclosures. Conductors entering enclosures within the scope of this article shall be ...


8

Depends. If the conductors are 6 AWG or smaller. There is enough free space. It's not a short radius conduit body. The volume is durably and legibly marked by the manufacturer. Only then can the conduit body contain splices. In your specific case, I don't see the volume listed in the specifications section on the Home Depot page. So you'd have to check the ...


8

No, you cannot. Unless you're not covered by National Electrical Code (or similar), you don't care about following codes, or you're also installing a permanent barrier or listed divider. National Electrical Code Chapter 8 Communications Systems. Article 820 Community Antenna Television and Radio Distribution Systems. 820.133 Installation of ...


8

NO! Regular couplings, those in the first image, are NOT pull points. Pull points are conduit bodies or boxes, or even those silly little elbows in the second image. My suggestion would be to install a conduit body at strategic locations. For your installation you really only need one. Conduit bodies:


8

Go out the bottom, otherwise the hole or any flaw in the conduit will bring water, rust and failure into your box. Use two conduit bodies to make your 180 degree turn. You can do this pretty tight to the box surface if you really want to. Do not strap the conduit to the box, strap it to the wall. Use THWN-2 wire in the cable. This is rated for outdoor ...


8

You mean 800.133. And this very concept of mixing comms and power is highly improbable. I know you're casting around for a way to do this, but this sort of "hopeful reading" is very highly prone to confirmation bias. NM-B is always useless in conduit Using NM-B in the conduit wiring method is not illegal, but buys you nothing but headaches. It's very ...


8

With rigid or intermediate metal conduit ($$) you can follow code without going very deep - 6" under dirt, 4" under a concrete cover of at least 4" thickness extending at least 6" to either side. Unless you want a concrete path through your garden along the route of the conduit, that's not likely what you want. Rigid and intermediate metal are tough enough ...


8

NM in conduit under a deck (or a slab) is NFG You cannot legally run NM cable in a wet location, and the inside of a conduit in a wet location (such as under your deck, or buried beneath a slab) is still a wet location. Don't believe me? Well, we start with NEC 300.5(B) for what's going on sub-slab: (B) Wet Locations. The interior of enclosures or ...


8

Too many circuits per pipe All this is about the derating rules in 310.15(B)(3)(a), see ThreePhaseEel's answer. When I first saw your other question, I thought "Oh boy, I smell a too-many-circuits problem coming". I thought I should warn you to run multiple conduit, but I didn't mention it because it was out of scope. Now, if you were strictly working ...


8

Speaking as someone who does a LOT of data cables... Pray to your deity of choice regarding (lack of) lightning nearby. The extent to which I prefer fiber optic for outside data runs is influenced by years of dealing with copper outside data runs, and the failures resulting - but few, if any, cameras are set up for power + fiber optic, so you'll want a nice ...


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