Blue Conduit?

Do these look like material approved for outdoor conduit?

I haven’t seen them before. They are made out of some sort of blue plastic.

Thanks in advance.



Smurf tube is corrugated PVC flexible tubing used to provide an easy method of upgrading structured wiring systems. The tube is run from the distribution panel to each outlet during the prewiring construction phase. Retrofit wiring can easily be pulled through the tubes without painstaking cable snaking. The most common type, Flex-Plus Blue ENT, is manufactured by Carlon, Cleveland, Ohio. Workers nicknamed it “smurf tube” because of its distinctive blue color.

**Why can’t ENT be installed outdoors? **
ENT was designed as an in-building product (see Article 362 of 2002 NEC). Since ENT does not have ultraviolet (UV) inhibitors added to the PVC compound such as our rigid PVC conduit, it is more affected by the ultraviolet rays from the sun. We know from experience that unprotected outside storage of ENT may result in brittleness in a 3 to 4 month period. ENT from the factory is stored with a white plastic wrap for storage and shipping to protect the product from the sun.

Carlon Website

Try here

Thanks, great answers. Now I know why I haven’t seen this outdoors!

Carlon may be overstating the UV damage aspect but it is listed indoor only so that is what you have to go by. I am using a piece of 3/4" smurf to sleeve the steering cable on my boat and it is doing fine 10 years later. I also have a short piece of smurf on the condensate line of my A/C that my wife moves around to water the plants, still OK.

Be advised also that ENT is not rated for protection against physical damage. Sometimes people will sleeve romex in ENT for “armor”, which is just silly. In the eyes of the code, ENT offers no enhancement with regard to physical protection.

I agree Marc, they do have similar language in regard to damage but our AHJ seems to like it more than exposed Romex. (garages and utility spaces)
This whole physical damage issue is so subjective it is hard to trust a ruling from day to day, AHJ to AHJ. There is really no hard and fast rule of what is subject to physical damage and when that potential damage is “severe”.
It is just one of those, “the AHJ knows it when he sees it” things.
Some places like Romex on running boards everywhere, others want it above 5’ or so, some always want it concealed and others don’t really like Romex at all. (I’m talking about you Will :wink: )
Usually where we see smurf in new construction is roughing in garage “coach lights” that get installed in grouted cells since it is listed for direct concrete encasement. You can also use it to sleeve through a tie beam or come through a floor slab into an island if it is in the pour.
They are supposed to dig it out a little deeper where the smurf goes to still maintain the 4" slab and keep the smurf in the concrete. YMMV

Marc, correct me if I am wrong, but I believe when you put Smurf in concrete you are required to use PVC fittings instead of Smurf fittings, as Smurf fittings are not concrete tight.

Not true. Smurf fittings are listed for concrete if they snap twice when installing. They are suprisingly tight if the end of the tube was cut in the groove.

Don’t know. I don’t use the stuff. Good practice dictates that any mechanical connection that will be covered in concrete get taped anyhow.

Hi. Mark;

Around here, the only place on commercial jobs that the blue smurf tube is used is by the control people for thermostats, low voltage, and hard to get places, add ons by the electrician to run additional conductors.

What is up with running in concrete in lieu of running pvc conduit buried in the ground away from all the abuse of pouring the concrete?

Never seen this stuff actually run and cast in concrete. Even though it might be approved.


Marcel :slight_smile: :smiley:

It’s fast and cheap. That’s about all I can think of.

I think you’d also have about a 90% chance of the flatwork guys stepping on it or running their mud buggies over it and having many places smashed flat. Sounds like a bad installation practice, to me, even if it is approved.

I said that I don’t run the stuff, but I guess that’s not true. I remember running it at least twice. Each time it was in metal studs, where the schedule got all messed up. I was in a hurry, and just left a stub of ENT stick out of the top of the wall, above the suspended ceiling line, from each switch and outlet location so that the rockers could get to work. Made more work for me later, but kept the schedule on track. Took a few days work and turned it into 6 hours. Of course, when I had to do the above ceiling work, that took way more time, but there was more wiggle room in the construction schedule at that point. I don’t want to be the guy responsible for taking a project off the critical path. That usually means you will not get any more work from that GC after the project is done.

Thanks Mark.

Fast and cheap, yes sir, seems like everything is being based on that today.

Problem here is cheap, in order for it to be material cheap, it also allows to be labor cheap.
Now you do not need electrians that know how to bend EMT and the lesser skills mean lesser pay, Unless in the Union.

One of these days, good skilled craftsmen will be a thing of the past.

Marcel :slight_smile: :smiley:

Fast and cheap, sounds like what Will says about Romex. He is right. That IS why Marc doesn’t run EMT in residential.

ENT is listed concrete tight, without tape. I can say, if the ends are dressed cleanly and “double clicked” into the connectors they are damn near water tight . Certainly better than traditional EMT compression connectors. (dunno about the “rain tight” ones).

You say this from all your years of experience installing electrical goods? :frowning:

Give me a break.

More old guys rambling on, pretending to still be relevant.

No Marc it is from “misusing” electrical materials. I have used ENT for all sorts on nonelectrical stuff, including as a hose. I bought a crapload of it when “Builders Square” went out of business. (all you can get in or on a cart for $25 and I filled 2 carts of stuff).

If I was a code wonk I would simply ask you if the manufacturer required that you tape a listed concrete tight connector. I bet you tape wirenuts and receptacles too.

No, I don’t tape wirenuts or receptacles. That is unnecessary. It has proven necessary to tape mechanical connections that are installed in a concrete pour to exclude the concrete.

Mark, we can’t have mechanical connections in concrete that is not accessible can we?

So there would be no reason to tape the connections. It needs to be accessible.
Just throwing this at you here. ha. ha.

Marcel :slight_smile:

Do what gets you through the night, to be absolutely honest I taped up the stuff I used in my bedroom remodel but after playing with this stuff for 10 years I do think it is a pretty good product.
Snapped together fittings 3/4" weeped water but they didn’t squirt on a 20-40 pump. We were mixing concrete 200’ away and we didn’t have enough hose to go that far.

[voice=three stooges]Oh, a wise guy![/voice]

I was talking about the mechanical connections of the raceway.