Keep sheetrockers from cutting wires

[Bzncrewjr]

What are best practices for keeping sheetrockers from cutting LV wires to stuff like alarm window sensors, speaker wires, cat5 cables?
 
I'm considering doing my own wiring of these in a new construction situation and want to prevent the wall crew from cutting my wires.
 
What is the best way to prevent this?
 
--Russ

 

[wkearney99]

Keep the wires tucked in behind the cut-out rings, or fully flush inside the boxes.  You can always leave some slack inside the wall.  Just secure it in a way that will be reasonably easy to dislodge it later. A cable staple gun works.  Just not a regular one, the flat edge will have a tendency to nick the cable jacket.  Insulated staples (the kind with the plastic) are more expensive but there's less risk to the wire.  Just lightly tack them in place.  
 
For ceiling locations I marked all of mine on the floor using a laser level pointer (bosch 3-point gpl3).  Aimed the laser up to where I left the wire bundle, marked the subfloor and then made an X/Y measure from nearest walls.  Took pictures of the markings on the floor.  Also took pictures of ALL wall cavities and ALL equipment placement (pipes, ducts, wires, etc).  This way I can just mark off the X/Y on the floor and know where to find the wires.
 
Where is gets problematic is if the wall cavity is going to be filled with spray foam.  That being the case you really have to be precise about leaving just enough wire in the box to keep it flush, without being too short to terminate on connectors later.  But for regular batt insulation it'd be OK to have extra wire in there.

 

[kurtmccaslin]

I pre-wired my house about a year ago and did not have any problem with the drywall guys cutting wires.   (that I know of.   I have not terminated all of the wires yet)
 
I stapled the wires to the studs every few feet to keep the wires away from the drywall.   I used a LV staple gun as Bill suggests.   They will use a rotozip to cut out your junction boxes, so push the wires to the back of your boxes if you are using closed boxes.    If you are using the orange LV boxes, you can just staple a loop behind the box.   I used the blue closed boxes on the outside foamed walls, and orange LV boxes on the interior walls.
 
There is risk that the trades will damage your skinny little LV wires.   My builder suggested that I do the wiring after the HVAC techs, plumbers,and electricians were finished.   Unfortunately, the schedule did not work that way and I was out there with the rest of the trades.   However, I was careful to wire in the section of the house where they were (mostly) finished working.
 
There is also the risk that the drywall crew will sheetrock over your junction boxes.   This is where good photos help a lot to locate and dig the wires out of the wall.   This happened to me 3 times.
 
If you run your wires too close to the edge of the studs or plates, there is risk that the drywall crew will screw into your wires.   If your wires are closer than about an inch from the edge, you need a nail plate over the stud to protect the wires.    You can watch how the electricians and plumbers handle this.   They obviously have a lot of experience with drywall screws.
 
I talked with my electrician and agreed that he would run all of his wires in the attic low, and I would run my wires high.   They prefer to run the wires on the floor of the attic because it is easier.   I ran all of mine in J hooks near the roof.   It kept the wires out of the way of the trades, and it kept my wires away from the HV lines.  

 

[wkearney99]

I spent a good while and a fair bit of change to get nail plates to block anyone from wrecking the wires.  I was there during a bit of the drywall and heard them bitching about the plates every so often.  But my wires stayed undamaged.
 
I mentioned pictures, TAKE PICTURES.  Digital makes them essentially 'free' and you never know what the future will bring that seeing 'under the covers' might help.  One of my ceiling fixtures is in the 'wrong' place for the furniture we want to use there.  Pictures reminded me the fire sprinkler pipes are in the desired location, whoops.  My decorator only recently found a suitable fixture.  The raise/lower AND two-point mounting option will work nicely.  
 
It may be too late to make the kind of design changes necessary, but it really helps to think about how furniture changes or different sizes might be impacted by hidden infrastructure.  Had I thought about this light situation I'd have gotten the sprinkler guy to run the pipes in another direction and drop the head just a few inches away.   The same kind of thinking could apply to pipes placed dead-center in walls (picture hanging issues) or ducts behind where something hung with wall anchors needs to go.

 

[pete_c]

Personally here with two builds just used metal mudplates.
 
I also politely told the GC he would have to redo my LV and alarm companies LV if any wires were cut.

 

[wkearney99]

I also politely told the GC he would have to redo my LV and alarm companies LV if any wires were cut.

 
Yeah, I hear ya, but unless you're the GC that's not always realistic.  As in, while they might be building "your house" it's "their construction site" and they're obligated to follow local building codes and avoid shenanigans with unlicensed contractors (aka, the homeowner DIY).  In which case you're kind of at the mercy of them 'ignoring' you and the work you're doing.  Otherwise it's less trouble for them to just use their own subcontractors.  I can totally understand why a GC would take this stance.  You're essentially an unknown and wiring screw ups or delays you might cause could impact a lot of other things on the GC's schedule.  That and some jurisdictions have permitting and licensing requirements even for low voltage.
 
So it's often best to plan to keep things as professionally done and out of the way as possible.  

 

[LarrylLix]

Even if you were an 'on payroll' contractor when minor damage is done the contractors all come back and fix it up, gratis,  as part of their agreements. Of course they never like it.

 

[pete_c]

Understood Bill.  In the 1980's did have to micromanage a few GC's who appeared clueless to me when doing some commercial stuff. 
 
Yes; initially I personally asked the GC to quote me for the LV runs and show me the type of work right before construction having penciled in what LV I wanted to add. 
 
At the time there were no LV residential building codes in the area. 
 
I said no to GC after seeing his work and what he wanted to charge. I then asked for 2-3 days after the electric / alarm was done and before the drywall went up to be alone in the house. 

 

[Del91574]

Even if you were an 'on payroll' contractor when minor damage is done the contractors all come back and fix it up, gratis,  as part of their agreements. Of course they never like it.

20+ years in the industry, it's always a billable call if you need to repair damages done by "others" unless it's because of the LV contractor's workmanship. I don't know of too many that would roll a truck and a tech to repair wiring for free.
 
That said, if you're on the site with X or Y trade and they hit a wire, usually a handshake deal to inform rather than allow the surprises after the fact would be typical. That would also assume the LV contractor was on the job or in proximity.
 
Usually, with any job, there's some sort of collateral of one shape or form, be it buried wires, nicked or cut wires or something similar. Nature of the beast, even in ultra high end jobs.
 
Hell, I've had entire boxes, rings or baffles buried behind sheetrock or even a 4" square just about completely filled with mud leveled to the wall. In angrier days, when doing large projects, after the rockers buried a bunch of boxes and other items, a coworker came out with a hammer and "found" where he thought the boxes were (with extra spite holes involved) on a bunch of units (luxury condo complex) which the rockers had to repair. From that point on, there weren't too many problems on that site.

 

[Bzncrewjr]

Where is gets problematic is if the wall cavity is going to be filled with spray foam.  That being the case you really have to be precise about leaving just enough wire in the box to keep it flush, without being too short to terminate on connectors later.  But for regular batt insulation it'd be OK to have extra wire in there.

 
I believe the builder does a lot of spay foam on exterior walls.  
How do you prepare for this?
 
So keep the wires pushed to the back of boxes?   
 
Is there a general rule for stapling wires?  Center of studs?   Nail plates should work for horizontal wires through studs.   However, how do you run vertical wires so sheetrock screws won't catch them?  Do you run them between studs?
One area I'm concerned about is door and window alarm wires.  How do you bury them so their rotozip won't cut them?   These are the most fragile of wires I would think.

 

[wkearney99]

Well, if the walls are foamed then you're not going to be able to leave anything in the cavity.  For those locations you may want to consider using conduit (blue 'smurf tube').  That way you can run the cable through later.  It's an added expense, of course, but it does offer versatility.  You don't have to run the conduit all the way back, just to somewhere nearby that would act as a convenient pull point.  I put conduits like that in all exterior wall locations that might need it later. 
 
How do you avoid rotozip damage?  By having the contractors either not use them or make it clear who's going to be back to repair things they damage.  For me it was a simple matter of regularly buying the crew lunch or drinks.  Bribing them with kindness makes it easier to get them to put a little more respect into their work.  As in, hey, I know all this wiring is hassle, but can we find a way to avoid things getting wrecked?  Not one got nicked.
 
Decent drywallers aren't going to want to waste time or materials.  A lot won't even use screws, but prefer drywall nails.  They're less expensive and don't require anything more than the right hammer (no drills to keep charged).   
 
One idea to consider is if you have a choice, always put your wires away from where drywall NEEDS to be fastened to the wall.  As in, not close to the edges of where a panel will end (door frames, corners, etc).  Run the lines down the adjacent side of the stud instead, or in another bay entirely, when possible.  

 

[Bzncrewjr]

I need to talk to the builder about insulation.   Maybe I'm getting it wrong.   I saw on other builds he blows in foam.  However, I think it's to seal, not as primary insulation.  What I've seen is foam blasted into cracks and corners.  It didn't look like the full exterior wall.
 
I agree with the food bribe.   A little honey (or lunches) can go a long way to make subs more considerate.    Probably not a good idea to buy beer for them if we want careful cuts. 
 
We are a long way from pulling cable.   I'm trying to learn all I can now so I don't look stupid or make mistakes later when the build is in full swing and I don't have time to research this stuff.  I've learned about cable quality and types as well as tools.  I've pulled cable before in built homes and it's a PITA.   I'm hoping pre-sheetrock cabling will be easier.    I also hope to pull lots of wire to EVERYTHING for future proofing.   
 
Digital photos are a must.  Any tips on this?   Like using a tape measure in the shots for distances?   I like the idea of XY coords and laser level on the floor.  
 
What considerations do the sprinkler heads create?  
 
 
--Russ

 

[kurtmccaslin]

Foam expands after it is sprayed in.   This can cause your wires to be pushed out-- and then the foam crew cuts them off as they are shaving off the excess.   When running wires in foamed walls, I stapled them about every 2 feet with a LV wire stapler-- in the center of the stud.   Then I terminated the wires in a HV (closed back) junction box.    For the doors and windows, I just drilled a hole in the window sill or door frame-- pulled the 22/2 or 22/4 wire through the hole and tied a knot in the wire.   The knot keeps the wire from pulling back into the wall cavity when the foam is installed.
 
For the digital photos, I just shot every wall in every room.   Including the ceiling.   I found myself blowing up the photos to look at the details so the 8 meg photos were a benefit.   Even so, there were some additional photos that I wish I would have taken.
 
I am not a camera expert, but I had a little problem with my camera not recovering fully between shots.   Aparently it was able to take photos faster than it could write to the card.   I was taking a lot of photos in a short time and just overloaded my camera.   Then I would have to wait for a minute or so for the photos to soak in.   I got impatient and did not take as many as I should have-- it was getting dark.   You might want to test out your camera on a high volume before you get to wiring stage-- if nothing else, so you can budget enough time for the photography.

 

[wkearney99]

Yep, you do need to have the wire secured so that foam, or anything/anyone else doesn't move them.  No just leaving them hang loose.  
 
Had I known ahead of time I wouldn't have used a split box for locations on the outside walls.  These have a closed back for the line voltage and an open back for low voltage.  Instead I'd have left the line voltage in a single box on one side of the stud and put a 2-gang closed box on the other for the low voltage stuff.  That would have left me a lot more room for excess length.  For the open boxes I fashioned a bit of tape across the back, making enough of a barrier to keep the foam from filling it.  It worked, thankfully.  Were I to do it again, it'd be closed back boxes anywhere there's foam.  Lesson learned.
 
Yep, I used a Nikon D80 with an 8gb Eye-Fi card.  It sent the pictures off from the card as I was taking them.  Didn't take more than 8gb at once but it was nice to have the card do the transferring for me.  Otherwise, yeah, use a good camera (not just your phone) and have a fast card in it. 
 
I also went around with a camcorder; two actually.  One being a flip, the other being an HD Canon.  The latter was overkill, but again, it's best to have the footage and not need it.  Footage, heh, there's some retro terminology.  Like dialing a phone...  Anyway...
 
I have over 3000 during-construction pictures of our 4 bedroom, 5k sqft house.  Most taken from the center of the room.  All aimed toward some part of the infrastructure and following it.  With plenty of overlap, enough to allow making panorama shots (not that I've needed them).  Bytes are cheap, take LOTS of pictures.

 

[pete_c]

Here the new construction prewiring done by an alarm company for outside walls with foam was no issue for me.  I did not take any pictures but depended on my modified drawings of their LV wiring.  The wires were not terminated and just labeled on one side.  The main floor of the home was concrete stucco and all of the doors and windows and sliding glass doors used foam insulation.  I was able to pull on the wires in the foam and terminate them just fine.  I did also use a toner to validate labeled ends anyways.
 

 
While I didn't micromanage the GC I did always visit once a week and reviewed all work done and did have the GC redo a few things that were not to my liking.  I did have annoying delays where I did have to do variable thumb presses on the GC.
 
GC subcontracted a guru alarm company to do the prewiring and I did my LV wiring in about 2-3 days.
 
The neighbor doing similiar new construction ran LV cabling in the middle of the upper sections for his CCTV which looks a bit tacky.  (CCTV points to his boat(s) / docks).  Here I just ran it to ever corner of the roof (along with HV for spots).
 
Personally initially here terminated the audio stuff within about a week of moving in.  The audio was 4/2 / 16 guage and one cat5e to the center closet of the home.  (I have a pair of in wall speakers in every room of the home - literally including three bathrooms, garage and Lanai).
 
The OmniPro security and lighting stuff came a year or two later.