New Home With "Structured Wiring Package" - What Do I Ask?

[RichardU]

So how do I terminate the cables when I prewire? Should I get a low voltage box and make sure the drywall guys know not to cut out for it, or can I just staple it to the nearest 2x and leave them there? We're planning to spray foam the house as well if that makes any difference.

I spray foamed my entire house. Once the spray foam goes on, it will be difficult to move any wires "in" the wall. Make sure you have more than enough slack outside the wall that you can stuff back in later. I got screwed over by this when my painters messed up a couple of pressure switches. I tried to replace them, but the wires were stuck too far back in the wall to reach. Even though I could grab them with needle nose pliers, I could not pull even an inch of slack.

As for the "home" end of your home runs, just coil your slack in piles on the floor. You might want to put the coils into garbage bags and seal them. Otherwise they will be filthy by the time you use them. Also, to hold the coils use wire ties, not electrical tape which will get gummy. For that matter, get some threshold protectors and cover all your thresholds in the house (more lessons learned the hard way.)

Finally, you will want all your wires to be tidy in your panel(s) so eventually you need to cut them to length. But what if you ever need to reconfigure your panel? You could do what I did. My panels are attached to a 4x8 sheet of MDO which is nicely painted white. But instead of nailing the MDO to the studs, I just hinged it at the top. Now I can leave slack in all my wires, but it's behind the "wall" so everything is neat and tidy on the outside, but I can get behind my panels by pulling the MDO forward. The rest of the time, the weight of the panels keeps everything solidly in place.

 

[EmagSamurai]

Do I understand correctly that you are suggesting I just pull an extra foot or so of wire at the device end, and leave this hanging outside the wall when the spray foam, and then push this back into the wall before they drywall?

 

[RichardU]

Do I understand correctly that you are suggesting I just pull an extra foot or so of wire at the device end, and leave this hanging outside the wall when the spray foam, and then push this back into the wall before they drywall?

Exactly. I'm glad you can learn from my mistakes.

 

[tmbrown97]

If you're using spray foam, I'd personally use conduit instead of running wires for any of those boxes, and put gang boxes at all the right locations. Spray foam is like glue to anything it touches and you'll never be able to do anything in that wall again without removing the sheetrock and carving a channel out of the foam. The stuff is a great insulator, but absolute hell for future-proofing unless you have conduit that goes everywhere you would need.

 

[EmagSamurai]

I remember code says you can't have a junction box covered in the wall. Does that apply to LV wiring as well, or will I be able to leave the jbox with the wires installed and cover with the drywall?

 

[RichardU]

If you're using spray foam, I'd personally use conduit instead of running wires for any of those boxes, and put gang boxes at all the right locations. Spray foam is like glue to anything it touches and you'll never be able to do anything in that wall again without removing the sheetrock and carving a channel out of the foam. The stuff is a great insulator, but absolute hell for future-proofing unless you have conduit that goes everywhere you would need.

I'm the world's biggest fan of conduit, but I wouldn't use it in a location where I only need a security wire. Plus, foam applications do not necessarily fill the wall cavity, particularly if you have 2x6 studs.

 

[RichardU]

I remember code says you can't have a junction box covered in the wall. Does that apply to LV wiring as well, or will I be able to leave the jbox with the wires installed and cover with the drywall?

Where I am you can do pretty much whatever you want with LV, except mix it with line voltage. But the real problem isn't the junction box, it's what happens inside the junction box. If you have a splice of any kind you would want to be able to get to it, because it could always be a point of failure. I would say no splice, no problem, except that no matter how many times you tell your drywall crew, they will cut holes around every box, even when you don't want them to. I told my drywallers to leave a mechanical closet bare but they did it anyway. So I had them rip it out. The next day, a different crew put the drywall back. So I had them rip it out. The third time they put it up, I just let them finish. As has been pointed out, contractors do what contractors do. If you want anything different than the usual, be prepared to redo it.

 

[EmagSamurai]

As a bit of a side note, I was considering just running a conduit to each of my windows (no jbox, just a conduit with a pull string) rather than trying to run a 16/2 and a Cat5 now. However, I noticed today that running the conduit may be easier said than done. The house has an engineered flooring system, and they're using engineered beams for headers across the outside walls where windows are. The result is I can't fish a wire or conduit down from the top because it's a solid beam. Also, based on the way they're framing the windows, I'm not sure there will be a cavity between each window for me to get a wire or conduit in. This will essentially leave me with the option of running one large shade to cover all the windows rather than individual shades for each. Unless I decide to go wireless, that is.

Has anyone run into this situation with their windows?

 

[RichardU]

Has anyone run into this situation with their windows?

If you are automating shades the location for the wiring will depend on the exact model you get. You can almost always figure out a way to get a wire in, but maybe not conduit.

Also, the easiest way to get a pull string in a conduit is to wait until it is finished, grab a hunk of plastic from a plastic grocery bag, tie it to your pull string, and stick it into one end of the conduit. Use enough plastic so that when it is balled up, it fills the pipe, but not tightly. Then go to the other end of the conduit and hook up a shop vac. The pull string will be there within a second or two. Very fast. You don't even need to make a great connection between the vac and the conduit. Wrap a rag or your fist around the connection and it will have enough suction to pull the string.

Wireless means batteries. Ugh.

 

[wuench]

Does spray foam fill the entire cavity, I saw it on a show and it looked like there was space left in the cavity, maybe about half?

 

[RichardU]

Does spray foam fill the entire cavity, I saw it on a show and it looked like there was space left in the cavity, maybe about half?

Mine didn't. Only needed 2" and my outside walls were 2x6 studs, or about 5.5". But the spray will lock your wires in place.

 

[EmagSamurai]

Our spray foam quote says 3.25" and we have 2x4 walls. So there will undoubtedly be areas where excess has to be trimmed off as well as some areas with a cavity behind the drywall.

 

[jaydubb1]

2x4's are not 2"x4" of course... sounds like it will be tight but doable.

 

[EmagSamurai]

The spray foam contractor said they take off the 1/4" to help minimize waste. If they tried to apply exactly 3.5" they would have waste at every section of wall, and that extra 1/4" doesn't provide a great deal of insulating value.

 

[rismoney]

I decided against spray foam on my recent new home build. I was concerned that it would be the next asbestos, except impossible to remove.
I then looked at nearly every other type from blown in solutions, to denim and ended up with fiberglass batting. And yes I watch Holmes on Holmes religiously, and see him put it on every install.