Ent smurf tube

Status
Not open for further replies.

keith gigabyte

Senior Member
I have heavy industrial commercial experience. I hear a lot of guys using smurf tube. I assume they mean flexible non metallic tubing? Other than connectors are there device boxes rated to accept it without additional connectors?

Thanks
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
Art 362 covers electrical non metallic tubing , or shmurf pipe , the associated box fill(s) are considered along with any other raceway

~RJ~
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
A box with a build-in PVC hub will also accept ENT. The OD and material of ENT and PVC are identical. See the UL White book.


We've all done it, even had my AHJ walk past it, but technically one may not be 'listed' fro the other

You know how manufacturers can be.....

~RJ~
 

peter d

Senior Member
Location
New England
It is absolutely awful to pull wire through it. I would avoid using it unless absolutely necessary. That being said, I know it's all the rage now especially for slab work.
 

fmtjfw

Senior Member
We've all done it, even had my AHJ walk past it, but technically one may not be 'listed' fro the other

You know how manufacturers can be.....

~RJ~

UL White Book:
Electrical Nonmetallic Tubing [ENT] (FKHU):
....
Fittings -- The outside diameters of ENT are such that standard connectors, couplings, and outlet boxes, for rigid PVC conduit can be employed for ENT that is also constructed of PVC. ....

So the AHJ rightly just walked by.
 

kwired

Electron manager
Location
NE Nebraska
It is absolutely awful to pull wire through it. I would avoid using it unless absolutely necessary. That being said, I know it's all the rage now especially for slab work.

Careful routing and securing does make a difference. If it is secure enough that it won't try to move with the conductors when pulling them you have won a major part of the battle.

Otherwise the fact that it is corrugated inside means less raceway to conductor contact surface and should pull easier then smooth walled PVC pipe with same number of bends.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
It is absolutely awful to pull wire through it. I would avoid using it unless absolutely necessary. That being said, I know it's all the rage now especially for slab work.
Agree. It is the worst stuff in the world to pull through. Worse than pulling through galvanized rigid. Worse than pulling through dirt for that matter.

Careful routing and securing does make a difference. If it is secure enough that it won't try to move with the conductors when pulling them you have won a major part of the battle.

Otherwise the fact that it is corrugated inside means less raceway to conductor contact surface and should pull easier then smooth walled PVC pipe with same number of bends.
You would think so. The corrugated surface idea makes sense on paper but for some reason it does not work out that way in real life.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
You would think so. The corrugated surface idea makes sense on paper but for some reason it does not work out that way in real life.
On paper it looks like you have to absolutely avoid any edges on the lump made as you transition from the pull rope or tape to the wire. Smooth and tapered with no steps along the side which might not be a big deal pulling through a smooth raceway.
But it sounds like that is not enough by itself.
Does Simpull (TM) work well in ENT?
 

ADub

Senior Member
Location
Midwest
Occupation
Estimator/Project Manager
I've never used smurf tube but it can't be worse than pulling through aluminum rigid can it?


Sent from my iPad using Tapatalk
 

oldsparky52

Senior Member
Careful routing and securing does make a difference. If it is secure enough that it won't try to move with the conductors when pulling them you have won a major part of the battle.

Otherwise the fact that it is corrugated inside means less raceway to conductor contact surface and should pull easier then smooth walled PVC pipe with same number of bends.

It's been my experience that if you let it be installed with a bunch of waves, it's harder to pull through and that's because you most likely have exceeded the 360 degrees of bends between pull points. If you take the care to not exceed the bend limitations it's pretty easy to pull through.
 

kwired

Electron manager
Location
NE Nebraska
It's been my experience that if you let it be installed with a bunch of waves, it's harder to pull through and that's because you most likely have exceeded the 360 degrees of bends between pull points. If you take the care to not exceed the bend limitations it's pretty easy to pull through.

It is sort of like most any flexible conduit. try to pull through an unsupported piece that droops and you have a hard time, Stretch it so it is straight, and can't try to bunch up while pulling through it and it is a lot easier. The trick is to route the ENT as straight as you can and have it as secured as possible. When you do make a turn, secure as near as possible to each side of the turn so it can't try to move while you are trying to pull through it. Unsupported deflections are the worst thing for pulling in any flexible tube of any sort, that isn't rigid enough to support itself from movement.
 

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
I'm not a fan. It breaks very easily at the corrugations if over-flexed. I use it frequently, however for low voltage installations to sleeve datacom wire from the drop ceiling to a low-voltage wall opening.
 

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
I've never used smurf tube but it can't be worse than pulling through aluminum rigid can it?


Sent from my iPad using Tapatalk

The corrugations make it difficult to pull wire. It snags a lot! It's terrible and I would never recommend it for long concealed runs.
 

kwired

Electron manager
Location
NE Nebraska
I'm not a fan. It breaks very easily at the corrugations if over-flexed. I use it frequently, however for low voltage installations to sleeve datacom wire from the drop ceiling to a low-voltage wall opening.
It is not a substitute for flexible conduits. It is flexible enough for ease of installation but needs a lot of securing and supporting when installed as well as physical protection - which means it should be installed in spaces where it will be concealed to limit physical damage. It has it's places that work great, it also has it's limitations. Long runs of rigid PVC are not all that easy to pull either, has more to do with it being PVC and less to do with it having smooth or corrugated walls. The corrugated walls do reduce surface area contact and make it easier to pull, but if it is not secure enough to remains still while trying to pull that adds more trouble then if it were a smooth walled rigid PVC conduit that won't move so easily.
 

readydave8

re member
Location
Clarkesville, Georgia
Occupation
electrician
I don't like smurf, whatever time it saves to install is same or less than time it takes to support and pull thru. Used it on a few of my early jobs, then switched to good ol' emt & "bx"
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
I have not used a lot of it, but I though the wire pulls were easier in ENT than in EMT....until you try to pull a couple of wires by the other ones...that was very difficult compared to EMT. As long as you were pulling all of the wires at the same it was great in my experience.
 
Status
Not open for further replies.
Top