vertical cable run strain relief?

[lleo]

I ran a 1 1/2" PVC conduit inside an interior wall between my basement and attic.
In the basement cables are supported by a wiring duct which ends right under the conduit.
 
I am looking for tips and ideas on how to secure the wires in the attic. For now, the conduit ends pointing vertically in a coupling cemented to the protruding end. The cables will make a 90 degree turn to run horizontally. While the edge of the piece is not particularly sharp, I am concerned about the weight of the 9' or so cable hanging on that turn. I could add an 90 degree elbow, but that will land the wires higher. In this particular conduit will have about 8 CAT6 cables, maybe more 22/4 later.
 
Any thoughts on vertical run strain relief? Thanks!

 

[tmbrown97]

Others may feel otherwise but 8 cables shouldn't present significant strain... but I would have a problem with them coming out and resting on a hard edge - I would want to soften that top exit.

 

[wkearney99]

I'd use a 90 degree sweep elbow.  They typically have a 1' radius (or thereabouts).  Then secure the cabling horizontally after it's exited the conduit.
 
Note, it's problematic to add cabling later.  The problem is the bundle going through there already is never 'even'.  It always ends up a bit braided in there.  Running more cable through later gets jammed up.  Worst yet, if you use a pulling tool that has any sort of hook that edge will rip the insulation of anything it contacts.
 
So, do not plan on running anything else through there more than one time.  Because any new cabling will just increase the amount of potential for more tangling later.  

 

[lleo]

Thanks for your input. In the meantime I discovered that there is a whole group of products called 'mesh grip strain relief' that come in various sizes. They are mainly for line voltage cables.  There is not a lot specifically for low voltage though.
The reason I ran a conduit is to be able to conveniently add wires over time, instead just sneaking in the wall a handful of category cables.
So here is my plan: will add an elbow, but will cut away the outer half, sort of making it a half-pipe. This way the conduit will have a vertical exit open, and cables can rest on a smoother radius turn. Once the first batch of cables are in, will form a bundle in the half pipe with a cable tie, about 1-2 inches from the edge and use a paper clip, or another piece of wire to 'hang' the cable tie on the edge securing the wires.

 

[Del91574]

Cable tie will cut through a Cat XX cable over time if there's any sort of weight involved, or at minimum start a bunch of issues.
 
There are plenty of hardware options to support backbone cabling, however the minimal amount referenced here isn't going to be a large enough bundle to be concerned about.
 
9' vertical is a trivial run to be concerned with the cable weight and real support. Fished cables have more than that in many installs.

 

[Photon]

I use a 90* sweep in the attic to maintain a decent bend radius, but it is not glued to the vertical conduit; it is a friction fit.  When I add a cable, I pull the sweep off the vertical run and slide it up the cables so I have a straight shot from the basement.  After I get a few feet of the new cable into the attic, I run it through the sweep with all the other cables, and then I stick the sweep back on the vertical run.  The cables are then attached to a nearby joist, but the first tie is far enough from the sweep that I can still slide it over the cables.

 

[wkearney99]

The reason I ran a conduit is to be able to conveniently add wires over time, instead just sneaking in the wall a handful of category cables.

 
Yeah, in theory that sounds good, but in practice the tangle inside the conduit will work against that idea.  The only way this works is if there's precious little in the conduit, it was pulled all together at once AND there's enough slack on both ends to allow some repositioning.  
 
I'll reiterate, do not plan on making multiple additions over time.  You'll be lucky to get one or two, it that.  Anything more than the force and tools necessary to try to cram more through it WILL likely cause damage to anything already in there.

 

[pete_c]

I am looking for tips and ideas on how to secure the wires in the attic.

Here I have one chase that goes from the basement to the attic.  Its been now some 10 years.  I did build a catwalk and added HV lighting to the attic mostly related to the LV wiring stuff before I started to LV cable the 2nd floor. 
 
As mentioned have a read about methodologies utilized.  Many of these depend on the number of cables/weight utilized.  You do have to be careful and over time you will see why.  Over the years I started with just a few cables later on adding commercial style support (as described) because it was made for this type of stuff. (cabling). 

 

[gatchel]

Yeah, in theory that sounds good, but in practice the tangle inside the conduit will work against that idea.  The only way this works is if there's precious little in the conduit, it was pulled all together at once AND there's enough slack on both ends to allow some repositioning.  
 
I'll reiterate, do not plan on making multiple additions over time.  You'll be lucky to get one or two, it that.  Anything more than the force and tools necessary to try to cram more through it WILL likely cause damage to anything already in there.

 
 
I'll have to disagree, I guess. The whole point of having conduit is to be able to add more over time. We have installed conduit all over the place and if you are careful, we rarely have issues except for when they are almost full. Even then, on straight pipe runs you can still get in a few more cables.
 
It you're talking about a 10-20 foot run from basement to attic, you shouldn't have an issue with adding more cables.

 

[JimS]

Cutting a 90 sweep to make a half pipe support is an interesting ideal although attaching the cables to it may not be needed.  I would cut off less than half so most of the side walls would be there to contain the cables.  I have rounded the inside edge at the end for a straight run but that still doesn't provide much radius.  Not a big issue unless you have a LOT of cables IMHO. Could make a radius support  out of lumber just above the exit if you needed routing in multiple directions. 
 
I agree about adding wires later being difficult and wires getting crossed up.    Pulling all the old cables and rethreading them all at once would eliminate the tangle issue but I can't see where that would ever be practical.  I have had mixed results adding cables.  I added a few cables to my vertical conduit but then ended up adding another, larger conduit beside the first.  I was lucky that the wall didn't have obstructions and that both top and bottom were accessible so it was pretty easy.  Put in bigger than you think you will need.

 

[gatchel]

 Put in bigger than you think you will need.

 
To add to this important detail....This is an understatement. Put in the largest conduit your wall cavity will allow. ( I know the OP said 1.5")

 

[pete_c]

Yup; here for my basement to attic chase post construction put in access panels on the main floor and the second floor which was a PITA to do.  The access panel thing was / is OK sort of.  The chase is only LV as there is no HV in the vicinity.
 
Choosing said space in the middle of the house and building it was very time consuming.  The old house had a stack or boxed area built from the basement to the attic.  The stack was much larger than what it contained such that I did utilize it for LV cabling from the basement to the attic.  (it was insulated sort of with double cavities for walls).
 
New construction around 2000 I did LV wire and build PVC chases as time allotted. 
 
Helped a friend in the last couple of years.  We had much more time such that we broke up the LV endeavor to stages relating to LV wiring.
 
Friend's new home is approximately 6 K square feet.  Guessing we used some 2K worth of wire all purchased in bulk.
 
We did run way more LV wiring than needed.  My guess is that much of it will probably never be used.  But its there anyways.  (all of the windows LV stuff is there but it'll probably never be used).
 
Personally my preference is to wire more than you will need using designated chases however they are installed and not immediately utilized.  Here the second floor is wired with much LV cabling.  In one room (home office) I have three areas relating to just network stuff today.  LCD TV MM area, "printer closet" and desk (well plus the zoned audio stuff and the RG6 cables).  Next to my desk I have 4 network runs to the basement.  1 is POE today.  Printer closet has 4 network runs to it and LCD TV (kind of big) has two network runs to it.  Note this is one room with 10 network cables run to it (not mentioning rest of stuff here).  Note today though if the house is really big; then you might as well build comm closets on each floor commercial style with WAF approval.
 
I am though doing these POE connected tabletop touchscreens and didn't want to pull a second catXX cable to an outside wall in the bedroom such that I used multiport POE 3COM (now HP) Intellijacks which are neat little devices.  (a tiny managed switch which utilizes a POE connection and fits inside of a single box).  I never actually used these little devices and never knew of them. It is a miniature managed 4 port switch the size of a single wall box.

 

[tmbrown97]

I always give the same warning about conduit not being a sure thing - and if asked to pull wire for a customer I make sure to have them sign off on something saying that I'll do my best to just add the requested wire, but it's very easy for things to get crossed up and damage what's already in there - if that happens, whatever I was attempting to pull and whatever's in the conduit could be trash and I'll have to re-pull it all - at the appropriate cost.  That said, I've never actually had the damage occur - I take my time and use lots of the cable lube.  I recently had to add a new cable to a 750' underground conduit that barely had the room - and it still went just fine.
 
In all reality, a vertical run - no twists and turns and 20' or less - you should be just fine.  Your existing pull string may get tangled up - you may need to use a fiberglass push rod to get a new string in there - just make sure it has no sharp edges to damage existing cabling.   I really don't think there's anything to worry about here.  These are all cautions from people who have likely been burned - but what you describe is about the easiest conduit in the world to work with.  Just oversize as much as possible.

 

[wkearney99]

These are all cautions from people who have likely been burned...

 
'zactly.  
 
For our new house I ran all known-need wiring without conduits.  Then I also ran the blue 'smurf tube' 1" conduit to boxes that might need additions later or were inside foamed insulated walls.  I didn't bother with ones having decent up/down access inside a wall cavity.  I then ran two empty 2" conduits from the attic down to the electrical closet.  They're a straight shot all the way down.  They're empty at this point, but they're there for 'future needs'.
 
In the old house that was on this lot (we tore down and built new) I also had some 2" conduit running up to the attic, and along inside some floor joists.  One was pretty well maxed out, but the other was about half full.  I succeeded in pulling two cables through it once, but it took some push/pull action in order to loosen the tangle of cabling in the conduit enough to let them pass.  I tried pulling another two some time later and it was a bear trying to get through, even with lubricant.  Which just made it that much more entertaining a hassle.  I still managed to do "something" to one of the CAT5 cables to disrupt it's ability to run wired ethernet through it (likely friction heat from a new cable pulled through a bit too rapidly, across too long a length of the braided tangle.  
 
So, yeah, lots of folks never seem to run into the problem.  
 
Had someone warned me about it (or if I'd read about it somewhere) I'd have probably taken the time to just run everything (and extras) all at once.  
 
But back to the question, I brought my stuff out the top/bottom using sweep 90 elbows that were just friction-fit onto the conduit.  The one at the top wasn't a problem, but I did use some screw-down zip ties to hold the one at the bottom.  Being able to pop them off the top/bottom did make it "less hassle" when trying to run stuff later.