Subscriber Discussion

How Would You Install Cabling On Concrete Ceiling With Insulation?

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Michael Silva
Dec 15, 2016
Silva Consultants

I have a parking garage project where we will be installing cameras at the end of each row to provide general garage coverage. The walls and ceiling are concrete, and the ceilings on many levels are covered with fiberglass insulation blankets. The blankets are about 10" inches thick and appear to be fastened to the ceilings with wires attached to the ceiling using powder-actuated fasteners.

The owner doesn't want to install conduit, but instead wants to install open Cat 5 cabling to each camera.

A couple of questions for my installer friends:

  1. What techniques would you use to fasten the Cat 5 cabling to the ceiling?
  2. Approximately how much labor would you estimate to run the cabling using these techniques? (per camera, per 100', etc.)

I would appreciate any input you can provide. Thanks.

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Ari Erenthal
Dec 15, 2016

You can hang threaded rod from the deck and then attach bridle rings or cable trays or whatever, but that'll be a nightmare. My advice is to sub that part out to an electrician.

Running conduit along the walls will most likely be your cheapest option here.

(1)
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Paul Grefenstette
Dec 15, 2016

bridle rings/jhooks mounted high on wall possibly wouldnt be that hard to run depending on the layout and maybe the only way if the entire ceiling is covered - are there any concrete beams exposed to attach hooks to or is everything covered by that awful fiberglass blanket/batting?

(3)
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Ari Erenthal
Dec 15, 2016

The real question here is how good of an idea it is to install cable that isn't in conduit, of course.

(2)
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Michael Silva
Dec 15, 2016
Silva Consultants

Conduit is always my preferred installation method, but here the owner has specifically asked that it not be used.

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Paul Grefenstette
Dec 15, 2016

I assume he knows the ~ cost of conduit so thats why he'd like to avoid? maybe I am wrong but having to install anything into that ceiling is going to be expensive in labor and materials thats why i'd recommend wall mount if possible

(1)
KL
Keefe Lovgren
Dec 15, 2016
IPVMU Certified

I agree with Paul, going around the perimeter seems like the easiest route. Shoot a laser to see what your potential path will be and pick the straightest path with the least amount of obstructions. Working along a wall is much easier than working overhead.

(1)
UI
Undisclosed Integrator #2
Dec 16, 2016

This is not unheard of. I recently completed a parking deck project with direct burial cabling in a large parking garage. The customer opted for the cost savings. Our risers and anything below 12' is of course in rigid conduit. In the year or so since installation there have been zero issues. In fact, the few issues we have had are with legacy cameras cabling that were installed in conduit. Non-flooded or taped cabling was used in those cases and whenever it rains we see problems.

However, nearly all of the rest of our parking deck projects are 100% conduit.

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Ethan Ace
Dec 15, 2016

I hate to say it but I'd think the real best way to do this is to use powder actuated fasteners to put J-hooks up wherever they're needed. Plan the runs out so you can minimize how many need to be done, but if that's how the blanket is held up there, I'd be wary of penetrating it another way. A drill might tear it or the fiberglass and/or plastic cover could end up wrapping around it. Then who's liable for repairing it?

I can't even begin to guess what that would cost. Because the fastening itself is fast, but I don't know what an electrical contractor would charge for the labor and a man to do it. Not every schmo knows how to shoot a Hilti.

(1)
UI
Undisclosed Integrator #2
Dec 16, 2016

Hilti guns with 10' extension rods and their combo clip/cable supports are a lifesaver. They have become so much a favorite that the 5 Hilti guns I bought have now completely displaced the lower cost Ramset units. Not to completely sound like a shill but I imagine Hilti has some form of clip that will work.

(1)
(1)
MI
Matt Ion
Dec 18, 2016

When you take a look at Hilti's product lineup, you realize they have a LOT more stuff than just the hammer drills and powder nailers that everyone associates them with. I'd be surprised if they didn't have something specifically suited to this job.

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Brian Rhodes
Dec 15, 2016
IPVMU Certified

I worked for a concrete building contractor in college, and those rolls of fiberglass insulation are miserable.

For mounting raceways and suspending light fixtures, these Ramset fittings are helpful. They make some that drop 4" - 5" from the compression collar, they might clear a shallow depth batt, but they may have models that go the 10" - 12" you need:

If you can find a seam between batts, or just drill a hole through them, these fittings can be pressfit into a blind hole and then pulled down to lock.

(2)
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Michael Silva
Dec 15, 2016
Silva Consultants

Brian,

Great info. The insulation is about 10" thick so I think we would need to add a wire to your fastener in order for the cable to lie at the bottom of the insulation without compressing it.

How long would you estimate that it would take the average installer to install 100' of Cat 5 cable using this technique (cutting hole through insulation, roto-hammering ceiling, inserting fastener and wire, attaching cable, etc.). Nothing I will hold you to - just your best guess :)

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Brian Rhodes
Dec 15, 2016
IPVMU Certified

I think for a single worker on a ladder, one fastener every 10 minutes is achievable.

In college, we worked on lifts and it took longer to steer/spot things and we could easily install at that rate for a long run. My foreman always yelled at us to hurry up, but I think he might have been that way no matter what. :)

Special tools include a can of compressed air to blow dust out of the hole after drilling is done.

(1)
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Brian Rhodes
Dec 16, 2016
IPVMU Certified

I should also add that we were drilling into relatively green, fiber reinforced (lower density) concrete that was typically poured a few weeks prior.

I can easily imagine drill time will vary depending on the concrete's age and density.

UI
Undisclosed Integrator #1
Dec 15, 2016

screw it, zip tie it to the pipe and be done with it.

(6)
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Michael Silva
Dec 16, 2016
Silva Consultants

Unfortunately, I have seen it done this way more times than I care to mention.

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Michael Silva
Dec 16, 2016
Silva Consultants

My thanks to all who provided input.

In many cases, a "cost saving" alternative ends up costing more than doing it the right way in the first place. But you need to know what the alternatives are so that you can present an intelligent case to your client.

(1)
U
Undisclosed #3
Dec 18, 2016
IPVMU Certified

Michael, is this a sprinkler/sensor/flashing light or camera? where are its wires coming from?

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Michael Silva
Dec 18, 2016
Silva Consultants

That device is a speaker/strobe for the fire alarm system. Conduits for this were installed in the concrete slab when the building was constructed. The conduits are stubbed down a few inches, allowing a back box for the speaker/strobe to be installed.

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Jon Dillabaugh
Dec 18, 2016
Pro Focus LLC

How about double expansion anchors with threaded rod, a threaded coupler nut, then a bridal ring.

Also, what is the purpose of the insulation?

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Michael Silva
Dec 18, 2016
Silva Consultants
Jon, yes that technique would work. The parking garage is unheated and the insulation is intended to prevent heat loss from the occupied floor above. Many new buildings in this part of the world have this type of insulation in the parking garages. I have also seen insulation added to several existing buildings, so it must provide some energy saving benefits.
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Joel Kriener
Dec 18, 2016
IPVMU Certified

Well, you could use j-hooks for hanging but as others have said here I would really question the 'not in conduit' implementation in the situation for at minimum mechanical protection of the cables for the long term. You could use heavily insulated, armoured UTP cable or use the common flexible plastic conduit along with the jhooks.

Its just not good best practice to leave exposed cable for any type of application.

are there any existing low voltage conduit runs that could be used?

Joel

UI
Undisclosed Integrator #4
Dec 19, 2016

Would it be possible to use fishstix to push the wire between the concrete and the insulation?

MI
Matt Ion
Dec 19, 2016

Well if you wanna be super ghetto and just get the job done, just strap the bundle to the buttons holding the insulation up. Yes, I'm MOSTLY being tongue in cheek... although I have had clients suggest things equally sketchy themselves.

Which brings me to my point: whatever method you use, document any disapproval or warning you have for the setup, and make sure the client signs off on it BEFORE you even begin.

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Ari Erenthal
Dec 19, 2016

If he wanted to ghetto-rig the job, he wouldn't be asking here. He'd be zip tying to the conduit and calling it a day.

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