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Can ENT (Smurf Tube) ever be used for 110v power wires?


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#1 miamicanes

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Posted 09 August 2009 - 11:35 PM

Is it ever legal under NEC to run power wires through BLUE (not orange) ENT conduit ("smurf tube") that's dedicated to that use (ie, NOT shared with low-voltage wires)? I spent a really frustrating hour at Home Depot this afternoon trying to buy conduit to use for power wiring. Frustrating, because every single conduit option I explored required at least one thing they didn't have in stock:

* 1/2" nonmetallic waterproof conduit? Only available in 25' and 250' rolls. Great... lots of waste, or way more than I'll need for the next 10 years worth of home improvement projects.

* 1/2" flexible metallic conduit? Same story... 25' and 250' only.

* 14/3 armored MC cable? You must be joking. They only have 14/2 and 12/3... but it's illegal to use 12/3 if the upstream wiring is only AWG14.

* 14/4 (14-2-2) Romex (different cable run than above)? Yeah, right. Then I woke up...

The only thing they DID have in abundance was 3/4" blue ENT conduit ("smurf tube"), and the connectors for it.

Assuming it's legal to use, I'd love to just use the Smurf tube. It's easy to cut, ridiculously easy to mate (no razor-sharp spirals to worry about), and it seems to be the ONE conduit option that Home Depot (and Lowe's, for that matter) seems to actually stock in useful quantities. The fact that someone found it necessary to explicitly define ORANGE ENT conduit as being for "low voltage wiring" logically suggests that blue ENT conduit could theoretically be used for high-voltage wiring, but I've never actually seen anything in writing that says so. Plus, it seems like even under the most pessimistic scenario possible, it would still be a net improvement over Romex and offer at least a tiny bit of extra protection against cuts/nails/drilling.

So... is it just outright taboo to even THINK about using smurf tube for high-voltage wires? Or is it possibly OK, as long as there are ONLY high-voltage wires running inside?

Edited by miamicanes, 09 August 2009 - 11:37 PM.


#2 ano

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Posted 09 August 2009 - 11:47 PM

Is it ever legal under NEC to run power wires through BLUE (not orange) ENT conduit ("smurf tube") that's dedicated to that use (ie, NOT shared with low-voltage wires)? I spent a really frustrating hour at Home Depot this afternoon trying to buy conduit to use for power wiring. Frustrating, because every single conduit option I explored required at least one thing they didn't have in stock:

* 1/2" nonmetallic waterproof conduit? Only available in 25' and 250' rolls. Great... lots of waste, or way more than I'll need for the next 10 years worth of home improvement projects.

* 1/2" flexible metallic conduit? Same story... 25' and 250' only.

* 14/3 armored MC cable? You must be joking. They only have 14/2 and 12/3... but it's illegal to use 12/3 if the upstream wiring is only AWG14.

* 14/4 (14-2-2) Romex (different cable run than above)? Yeah, right. Then I woke up...

The only thing they DID have in abundance was 3/4" blue ENT conduit ("smurf tube"), and the connectors for it.

Assuming it's legal to use, I'd love to just use the Smurf tube. It's easy to cut, ridiculously easy to mate (no razor-sharp spirals to worry about), and it seems to be the ONE conduit option that Home Depot (and Lowe's, for that matter) seems to actually stock in useful quantities. The fact that someone found it necessary to explicitly define ORANGE ENT conduit as being for "low voltage wiring" logically suggests that blue ENT conduit could theoretically be used for high-voltage wiring, but I've never actually seen anything in writing that says so. Plus, it seems like even under the most pessimistic scenario possible, it would still be a net improvement over Romex and offer at least a tiny bit of extra protection against cuts/nails/drilling.

So... is it just outright taboo to even THINK about using smurf tube for high-voltage wires? Or is it possibly OK, as long as there are ONLY high-voltage wires running inside?


I'm not an electrician, but I think the Blue is fine for 120V INSIDE the house. It is explained in article 362 of 2002 NEC. There is some good info here:
http://www.carlon.co...provedUses.html

#3 Neurorad

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Posted 10 August 2009 - 08:51 AM

Find what you want at a local electric supply store.

If HD/Lowe's has what you want, then great. Prob cheaper at the electric supply store.

I never see electricians shopping at Lowes or HD.

If the product exists, the electric supply shop would be more than happy to order it for you as well.

Customer service in electrical supply can be hit or miss (like any large warehouse store) - some salesmen act like they're federal employees, while others bend over backwards, at the same store.

HD and Lowes are good places to see, feel, and learn. Then, go to the electric supply store for what you really want.

#4 signal15

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Posted 10 August 2009 - 03:55 PM

I'm running 240v through it. No idea if it meets code though. Home Depot around here is not allowed to answer questions on code or they will get fired.

#5 miamicanes

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Posted 10 August 2009 - 08:04 PM

Well, so far, one cruel lesson I've learned about electrical supplies is that at least 10-20% of any manufacturer's official catalog is pure fantasy/bull$hit (take your pick), and doesn't actually exist for purchase anywhere... not even online. Just *try* finding a double-gang old-work box with 1/2"+3/4" punchouts for sale somewhere. Their unavailability at Home Depot & Lowes is a forgone conclusion, but even REAL electric supply stores don't actually sell them... at least, not in South Florida. It seems that down here, their inventories are so overwhelmingly biased towards new construction, and retrofit items aren't even on their radar, let alone on their shelves. They'll scratch their heads and admit they vaguely remember seeing them in the Carlon, T&B, or some other catalog, but that's as far as it goes.

Actually, that's been my single biggest frustration to date. I'll spend a day or two meticulously planning my wiring, agonize over different items until I find *exactly* the right ones to do the job effortlessly and flawlessly... then go on a 3-county holy quest to find someone who's even heard of half the items on the list. Then tear up the list in frustrated rage and try again the next weekend. Stir, rinse, and repeat.

I've officially abandoned all hope of EVER finding shielded cat5 cable anywhere besides online. Two weekends ago, I was in Orlando and made an afternoon pilgrimage to Skycraft. That store has wire and cable in sizes, styles, and colors I never even knew existed. They have something like 40 varieties of cat6/5/e... AWG24, 26, 28... stranded or solid... pick your insulation color. But forget about shielding, because that's the one variety they don't have. Sigh.

Oh, I also had another nasty shock this afternoon. I decided that since I've done all my low-voltage conduit with blue ENT, it would be nice to use Carlon's RED conduit for the high-voltage stuff. Good God... ~$200 for a 200 foot roll (including shipping), at the 3 or 4 places I managed to find selling it online (the two local electrical supply stores I hit at lunch didn't have it, though the second WAS nice enough to warn me that red and yellow are several orders of magnitude more expensive than Smurf Blue, so I wasn't *quite* as blown away as I would have otherwise been). Needless to say, I'm probably not going to be pulling red ENT anytime soon...

While I'm on the topic of ENT... does anybody make an "old work" open bracket that has mounting rings for 3/4" ENT connectors? You know, so you can pull the ENT conduit an inch or so beyond the wall, snap it in, then tilt the whole thing back into position and secure it to the hole cut through the drywall? Or an open-back bracket that has mounting holes for TWO 3/4" conduits? I could *swear* I remember seeing something like that at Home Depot or Lowes ~4-6 years ago, but there isn't even anything vaguely resembling that in Carlon's 2009 catalog... and it looks like the OnQ/Legrand/P&S and Leviton varieties are OEM'ed by Carlon for them and just differ with regard to the plastic color. My problem is that I have full access to the wall from BEHIND, but all the "new work" ENT brackets I've seen have a tab that has to go between the metal stud and drywall... and in this case, the drywall on THAT side is quite firmly attached.

Edited by miamicanes, 10 August 2009 - 08:15 PM.


#6 Neurorad

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Posted 10 August 2009 - 10:27 PM

I think my local HD carries the LV new work bracket, with some kind of fittings on the side(s), but I don't think I've seen old work.

I just checked the Carlon catalog, and I don't see an old work LV bracket with conduit fittings. You don't really need to fasten the conduit to the LV bracket, though it could make life easier. I think it would be difficult to retrofit conduit into a closed junction box - you need to glue and fasten outside of the box.

My local electric supply shop quoted me a higher price for the Blue Smurf tube, compared with the LV Riser Gard.

Newark Electronics will have your STP - but their website is tricky. Find a brand/model online, and then look for it at Newark. They must sell 20,000 different types of cable.

You could call Carlon, and/or Arlington, to ask about an online dealer rec.

I'm surprised the electric supply shop won't order stuff for you, though it would be easier for you to order it yourself.

Edit - just re-read, and noticed you have access from behind. Cut the 'tab' off the new work box, and screw it from the front through the side, and into the stud? If the conduit terminates just above the old work LV ring, it should be easy to grab a cable, especially if the conduit is secured to the stud with a 'D' ring.

I don't think the orange PVC conduit is 'waterproof'.

I assume you're losing your access from behind the wall, and that's why you need the conduit?

Edited by Neurorad, 10 August 2009 - 10:32 PM.


#7 miamicanes

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Posted 10 August 2009 - 11:18 PM

I'm not talking about orange LV Riser Guard... I'm talking about red and yellow ENT, like this:

Posted Image

I'm not actually sure whether the blue ENT the guy is holding is the same blue sold at Home Depot & Lowes, or is a darker & more "blue" blue, because almost ALL of the online prices I found for 1/2" and 3/4" ENT of any color were ~3-4x more expensive than the blue ENT sold at Lowes & HD.

I have access to the rear of the wall for now because all the drywall was removed from my bathroom (on the other side of the wall), so I'm taking advantage of the one opportunity I'll ever get to do the conduit properly. I'm even halfway contemplating a sprinkler or two since I actually have easy access to both the wall and water for the time being... but from what I've read, it looks like building codes get weirdly psychotic about sprinklers, taking the attitude that "less than perfect" is NOT "better than nothing at all" in situations where they aren't actually required. Apparently, they take the rather extreme position that the water supply has to be dedicated exclusively to the sprinklers, and has to be capable of fully satisfying the maximum possible water requirements of every single sprinkler running at once. If I can get away with putting one or two sprinklers on a branch fed by the shower's water supply, I'll do it in a heartbeat as a cheap insurance policy against a future fire since it would be crazy to NOT spend the $100 or so on pipe & sprinkler heads if I can do it legally. But that's the ONLY way it's going to happen. It just seems bizarre that the relevant authorities think it's better to have no sprinkler protection whatsoever than to have partial sprinkler protection where it can be done cheaply.

Edited by miamicanes, 10 August 2009 - 11:23 PM.


#8 signal15

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Posted 11 August 2009 - 10:27 AM

Why were you looking for shielded Cat-5? It's internally shielded from the twisted pairs, so unless you are running it in a very noisy environment (like next to an AC compressor) there is no reason you need shielded. And, you should be using Cat-5e or Cat-6, not Cat-5. IMO, Cat-6 is the way to go.

#9 Neurorad

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Posted 11 August 2009 - 12:10 PM

The color of the conduit will be somewhat moot, as it won't be visible.

You could splurge and get colored terminating connectors, or paint them.

Where is the conduit running, and what will be supplied by the HV wires inside?

Am I correct that you want to use conduit to allow for easy cable replacement, eventually?

#10 miamicanes

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Posted 11 August 2009 - 02:26 PM

The shielded Cat5 is for video (s-video + analog stereo now, component + spdif soon, and HDCP someday (if somebody ever makes a solution that costs less than the TV it's connected to).

I briefly considered RapidRun, but I'm pretty sure it's too thick to pull even a single cable through 1/2" conduit, let alone additional cables alongside of it.

From what I've read, for video-balun purposes, the cable's shielding matters more than whether it's cat5, 5e, or 6... and most real-world cat6 would barely pass certification as cat5 for 100-mbit ethernet if you REALLY subjected them to rigorous testing due to installation abuse or interference from adjacent wires. In fact, I vaguely recall reading here about a year ago that cat6 cable has higher slew than cat5 by definition, and is actually WORSE for analog video transmission than cat5.

As far as the red conduit goes, it was just one of those anal-retentive things that seemed like the right thing to do if it were cost-comparable to blue.

Right now, the conduit will have 5 wires: 2 switched hots, one unswitched hot for general power outlet use, neutral, and ground. When I originally wired the outlets along the wall, I used a Wiremold surface-mounted channel. I could theoretically run a pair of 14/3 Romex instead, but I really *hate* Romex and avoid using it whenever possible (I've accidentally cut and nailed into concealed Romex at least twice in my life, and neither event was pleasant).

#11 petec

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Posted 11 August 2009 - 02:49 PM

Here in the MW I prefer metal conduit for electric. When we were building here in the MW noticed that the builders in many local areas had gone to Romex. One of my construction requests (an extra) was that the electrician used metal conduit versus Romex. In NW indiana we built a home in the 1980's and also used metal conduit. Recently I helped a friend buidling a home in NW Indiana and noticed that the code had changed ((?) and the electrician used Romex thru out the home.

In FL we built a home and on the Gulf side and I notice there they only used Romex. Its been a while and I have had to add electric (outlets, lights and switches) both in the MW and FL. Its easier in FL because of the Romex even though I do not like it nor really think putting metal plates where the romex runs is really that safe. The house construction methodology was following some new FEMA guidelines and the codes had changed from previous but I really wasn't impressed with what I saw was "code" and methodology's used. Cement, foundation work, electrical, plumbing, roofing, etc methodology's were not what I was used to seeing in the MW. I mean FEMA made some changes to make the house more resilent to Hurricanes but none the less a category 3-5 hurricane would still do some major damage to the home. On the other hand if I were to drop the house I live in (recently constructed) on the Gulf coast in FL it would most likely withstand a Cat 3-5 hurricane better than what I have seen.

Here in the MW I have bent conduit and still would prefer to use it rather than Romex (which is allowed).

Personally the smurf tubing offers just a little bit more protection but not enough to justify the cost. Say sometime in the future you decide to "rewire" and maybe use a higher guage wire you may be able to pull the Romex out but I am not sure how easy it would be to put Romex back into it.

For low voltage wiring I did use some smurf tubing here and there (in my home and some peers from work) being first introduced to it relating to some network cabling runs that we had installed in our data center many years ago.

Edited by petec, 11 August 2009 - 06:32 PM.


#12 ano

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Posted 11 August 2009 - 03:20 PM

The color of the conduit will be somewhat moot, as it won't be visible.

You could splurge and get colored terminating connectors, or paint them.

Where is the conduit running, and what will be supplied by the HV wires inside?

Am I correct that you want to use conduit to allow for easy cable replacement, eventually?



Actually the color does matter and you can't spray paint them to change the color. Blue is for power circuits, yellow is communications, and red is fire alarms and emergency circuits. What you find at HD or Lowe's is not blue because they are making a fashion statement. :) They don't usually carry red or yellow because demand is lower. If the color is not correct, the inspector won't likely approve it.

#13 mustangcoupe

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Posted 11 August 2009 - 06:15 PM

Actually the color does matter and you can't spray paint them to change the color. Blue is for power circuits, yellow is communications, and red is fire alarms and emergency circuits. What you find at HD or Lowe's is not blue because they are making a fashion statement. :) They don't usually carry red or yellow because demand is lower. If the color is not correct, the inspector won't likely approve it.



Seeing as you sound in the know what is the orange for that is usually found at HD?

#14 miamicanes

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Posted 11 August 2009 - 07:19 PM

If the color is not correct, the inspector won't likely approve it.

Maybe... but from what I've heard, most inspectors aren't exactly thrilled about empty, unused conduit being run everywhere, either, because they KNOW you aren't going to go out and get another building permit before pulling any new wires through it. :)

In any case, it'll be a frosty July day in Miami before I get a building permit for anything not directly visible from outside the house ever again. It took the City ONE WEEK (literally... applied on Monday, issued the following Monday) to give me a building permit just to replace my central A/C with an equivalent unit after it died last month. No new ductwork, no new wiring, same size... just a clean swap-out of a rooftop package unit. Seven F***ING DAYS. In Florida, in the summer, with regard to a straightforward, noncontroversial central A/C replacement, that's not just wrong, it's a human rights violation. Wait, it gets better. The unit was finally swapped out ~2 weeks ago... the inspector is coming TOMORROW to check it. :(

Edited by miamicanes, 11 August 2009 - 07:28 PM.


#15 mustangcoupe

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Posted 11 August 2009 - 07:47 PM

and in those 2 weeks you NEVER turned it on once right :)




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