Smurf Tube Question ......

[Davies]

Q: Why not run Romex instead?

Q: Why not run Romex instead?

A: That actually crossed my mind. But I have only 4 home runs that are currently utilized. I do not know what the code has to say about running home runs ( romex ) out of the panel to junction boxes under the house, and maybe a few in the attic, and just terminating there - waiting for future use. Of course safety being the first consideration, the leads get wire nutted and even taped. And the breaker in the panel would be off and marked as "Spare". Of course this would not apply to a dryer, or stove, etc. where the HR goes straight to the load connection. So this is just for future outlets and lights using 12/2 or 14/2.
Thanks. again. - S.

 

[mxslick]

Why don't guys run pvc in slabs instead of smurf tube? That's all we run, it would seem like it'd be a lot easier to pull through and not too much more trouble to install.

Because it is a LOT more labor intensive to route around rebar, other trades' pipes and ducts, etc. One can lay about 3-5 times the footage of smurf in the same time it takes to cut and glue pvc conduit.

Smurf is a lot cheaper that pvc per foot when you factor in all the fittings and couplings too.

My experiences with smurf were not in slabs..I have been told that smurf embedded in slabs/concrete walls allows wire to pull easier than smurf that is just secured at intervals.

 

[iwire]

Because it is a LOT more labor intensive to route around rebar, other trades' pipes and ducts, etc. One can lay about 3-5 times the footage of smurf in the same time it takes to cut and glue pvc conduit.

Interesting, but still limited to 360 degrees of bend so I do not see the advantage.

And I doubt you in most cases it is 3-5 times faster.

 

[mxslick]

Interesting, but still limited to 360 degrees of bend so I do not see the advantage.

And I doubt you in most cases it is 3-5 times faster.

I agree 100% with you on the first statement.

But I would challenge you to a duel on the second: 100 feet (or even 50 feet) of run in a rebar grid with other trade's stuff already there. :grin:

The stakes would be a steak dinner. (I hate burritos). :grin:

 

[mikeames]

I you're using smurf in a house, why not just run romex instead? They seem to have similar uses and restrictions. Neither can be exposed to physical damage.

Pulling future circuits through closed walls is the only advantage I see.

 

[Cavie]

Smurf is the cats meow for boxes in concrete block for exterior lighting switches and outlets with poured cells and tiebeams.

 

[petersonra]

I am a fan of anything that works well for the situation at hand.

The only time I can recall seeing it used other than some short chunks here and there was in a parking garage down south somewhere, don't recall exactly where, but I was on my way home from somewhere stopped to eat, and right next to the restaurant they were building this parking garage.

The ground level concrete was about to be poured and there was this mess of rebar, mesh, blue tubing, metal pipes, PVC pipes, and other things that it looked like there were getting ready to pour concrete on. I think there was almost as much "stuff" as concrete.

 

[LarryFine]

I think there was almost as much "stuff" as concrete.

Tubular aggregate.

 

[kwired]

For those who claim ENT is harder to pull through than PVC - I was wondering why it is harder. I have not run any ENT for a long time and when I have run it, it was mostly shorter runs of 1/2 or 3/4 inch and whether it was pulling easier or harder was not necessarily noticeable.

In theory I would think it should pull easier if well secured so that it does not try to pull with the conductors and pull line. The reason is that with the corrugated wall there is actually less surface contact with the conductors than there would be with a smooth wall like rigid PVC has. In a poured slab where the ENT will not move while pulling it should pull easier than PVC.

 

[mcclary's electrical]

A: That actually crossed my mind. But I have only 4 home runs that are currently utilized. I do not know what the code has to say about running home runs ( romex ) out of the panel to junction boxes under the house, and maybe a few in the attic, and just terminating there - waiting for future use. Of course safety being the first consideration, the leads get wire nutted and even taped. And the breaker in the panel would be off and marked as "Spare". Of course this would not apply to a dryer, or stove, etc. where the HR goes straight to the load connection. So this is just for future outlets and lights using 12/2 or 14/2.
Thanks. again. - S.

Oh no,,,,,Please,,,,,,please,,dont' start that debate again:grin:

 

[petersonra]

For those who claim ENT is harder to pull through than PVC - I was wondering why it is harder. I have not run any ENT for a long time and when I have run it, it was mostly shorter runs of 1/2 or 3/4 inch and whether it was pulling easier or harder was not necessarily noticeable.

In theory I would think it should pull easier if well secured so that it does not try to pull with the conductors and pull line. The reason is that with the corrugated wall there is actually less surface contact with the conductors than there would be with a smooth wall like rigid PVC has. In a poured slab where the ENT will not move while pulling it should pull easier than PVC.

You would think so.

Most of the times I have seen it used is for short runs though, maybe < 20 feet.

Maybe the fact that it is not straight makes it harder to pull through in long runs. i don't think i have ever seen any larger than 3/4 or maybe 1".

 

[John Valdes]

Why don't guys run pvc in slabs instead of smurf tube? That's all we run, it would seem like it'd be a lot easier to pull through and not too much more trouble to install.

Or EMT? We always ran EMT in slabs on multilevel structures. PVC first floor. These were high rise buildings (south Fl.) like the one shown on the show.

We never had issues with other crafts stuff in our way and visa versa. Good planning I guess. Of course all levels except for floor 1 and top floor were identical.

 

[petersonra]

Or EMT? We always ran EMT in slabs on multilevel structures. PVC first floor. These were high rise buildings (south Fl.) like the one shown on the show.

We never had issues with other crafts stuff in our way and visa versa. Good planning I guess. Of course all levels except for floor 1 and top floor were identical.

Maybe PVC is cheaper? These days that seems to be the main thing that counts.

 

[mikeames]

For those who claim ENT is harder to pull through than PVC - I was wondering why it is harder. I have not run any ENT for a long time and when I have run it, it was mostly shorter runs of 1/2 or 3/4 inch and whether it was pulling easier or harder was not necessarily noticeable.

In theory I would think it should pull easier if well secured so that it does not try to pull with the conductors and pull line. The reason is that with the corrugated wall there is actually less surface contact with the conductors than there would be with a smooth wall like rigid PVC has. In a poured slab where the ENT will not move while pulling it should pull easier than PVC.

Surface area does not matter. It may seem like it does or it should but it does not. Simply put if you do have less surface area then you have more pressure on that smaller surface area resulting in the same friction. Its counter intuitive but I had to learn this the hard way after loosing a debate about tire size and friction/traction.

 

[WinZip]

On vacation some 8 yrs ago in the Outer Banks of N.C. I saw blue ENT run from disconnects to AC units , looked like crap to.

 

[kwired]

Surface area does not matter. It may seem like it does or it should but it does not. Simply put if you do have less surface area then you have more pressure on that smaller surface area resulting in the same friction. Its counter intuitive but I had to learn this the hard way after loosing a debate about tire size and friction/traction.

What about in a vertical run?

 

[petersonra]

On vacation some 8 yrs ago in the Outer Banks of N.C. I saw blue ENT run from disconnects to AC units , looked like crap to.

But it was functional.

I have seen it snaked down the voids in concrete block walls.

I have often wondered why it is Ok to run ENT as far as you want but you can only run 6 feet of LFNC

 

[kwired]

But it was functional.

I have seen it snaked down the voids in concrete block walls.

I have often wondered why it is Ok to run ENT as far as you want but you can only run 6 feet of LFNC

You can run any type raceway any length you want.

LFNC has different support requirements for longer than 6 feet than it has for shorter than 6 feet. Does not mean you can not have more than 6 feet.

 

[WinZip]

LFNC can be longer yes but also must be strapped / supported every 3 ft

 

[mikeames]

What about in a vertical run?

Same theory but the conduit would be more of a guide than a suport. Pressure and coeficient of friction based on the materials rubing against each other.


surface-on-surface
hook velcro-on-fuzzy velcro >6.0 >5.9

avg tire-on-dry pavement 0.9 0.8
grooved tire-on-wet pavement 0.8 0.7
glass-on-glass 0.9 0.4
metal-on-metal (dry) 0.6 0.4
smooth tire-on-wet pavement 0.5 0.4
metal-on-metal (lubricated) 0.1 0.05
steel-on-ice 0.1 0.05
steel-on-Teflon 0.05 0.05