# In-floor cable trough renovation: crazy?



## cpf (May 18, 2012)

So in the place I work we have a fairly large and high-traffic backstage area, all of which is a concrete slab. Right now, there is no easy and safe way to run cables across this area for intercoms, extra speakers, etc. everything must be taped to within an inch of its cabley life and even then people are tripping up in the dark. 

What I'm thinking is: is it possible to (get a contractor to) cut a 1-2" trough into this concrete slab to make running cabling easier? Does anybody else have such a setup? I'm concerned about how the plates that would cover the trough would stand up to the parade of heavy equipment and herds of people that moves through the area daily.


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## len (May 18, 2012)

Any chance of going up and over?


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## SteveB (May 18, 2012)

We started using rubber backed carpet runners, either 3x6 or 4x? sizes. We lay them over pretty much all electrical and audio and have no tripping issues. If the cable is thicker, say 6/5 or so, we use a Yellow Jacket.


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## Morte615 (May 18, 2012)

This is really common in outdoor situations, pretty much you are looking for a strip drain without the drain. First thing is to make sure that your concrete is thick enough and make sure that cutting into it will not cause undo stress. These items should be looked at by an engineer.
Usually this would be added while the concrete was being poured but I don't see any issue with cutting it out after. Leave a lip around the top just deep enough for your cover material (usually grates or solid steel plates) so that once the cover is on it is level with the surrounding surface.


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## Lambda (May 18, 2012)

Is it possible to set up a raceway (like used for LAN cables) on the ceiling or wall?


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## Chris15 (May 18, 2012)

The Entertainment Centre here in Sydney has a cut trough the entire length of the arena from Stage towards FOH.
It's probably 8" by 4" which is the kind of size that can cause structural issues if you get it wrong.
Its top is solid steel plate and it looks like it has survived a fair chunk of things over the years.


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## MNicolai (May 18, 2012)

You don't have to go with a permanently cut trough. You could dig a little deeper, drop 4" or larger PVC or structural piping in the trench, then pour concrete again back over the top of it.

We use a 4" or 6" PVC piping network in the concrete that gives us cable paths from the control booth to:

1) 1st row of audience
2) orch pit SR
3) orch pit SL
4) house right
5) house left
6) mid-house mix position
7,8,9) some other places

We just leave a long enough piece of rope in each pipe to make the cable pull with. Some cables are for overnight use, others have become permanent components of our facility's infrastructure.


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## neotrotsky (May 19, 2012)

len said:


> Any chance of going up and over?



I have to agree: Better to go above than to start cutting for a non-facility function item like secondary telecom. And going up would be cheaper than going down, because when you get into cutting and laying concrete, it gets expensive fast. And, I noticed you're in Canada: You could have provincial building codes that would require a permit even (many federal venues, like mine, have insane rules that make no sense we have to adhere to before ANY modification of ANYTHING)


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## cpf (May 19, 2012)

Ok well I talked to TPTB and they don't want channels cut anywhere. I've looked at running trays along the wall, except that the entire back wall is full of cabinets that would make it rather challenging.

Since there is a catwalk running along the cabinet-obstructed back wall, I could see about overhead cable trays there. The one question I have is access: is there a way to get cables into the trays without hauling around a ladder? I've seen some trays with one side open, but I can't imaging throwing mic, cat5, etc. cable into them from 7' below...


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## johndeniel (May 28, 2012)

I am not sure about your idea but you can try to fish tap. First, you drill the hole and insert the cable up to your target region then place your circuit box.


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## derekleffew (May 28, 2012)

cpf said:


> ...The one question I have is access: is there a way to get cables into the trays without hauling around a ladder? ...


I've found that a J-shaped hook on the end of a long stick (10' 1/2" TWC) works nicely. If you're real good you can even remove cables out of sequence in which they were installed. In olden times we used a stage brace for this. Lots of J-shaped hooks and/or dinosaur track on walls, especially over doorways, is a good thing.


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## chausman (May 28, 2012)

derekleffew said:


> In olden times we used a stage brace for this.



We used a 10' stage brace for that about two weeks ago. Wasn't fun.


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## museav (May 28, 2012)

cpf said:


> Since there is a catwalk running along the cabinet-obstructed back wall, I could see about overhead cable trays there. The one question I have is access: is there a way to get cables into the trays without hauling around a ladder? I've seen some trays with one side open, but I can't imaging throwing mic, cat5, etc. cable into them from 7' below...


I don't know if you have similar requirements, but in the US ADA and OSHA include requirements for anything protruding more the a few inches from a wall the effectively make it necessary for them to either make the space directly below inaccessible or be at a sufficient height to not represent a potential danger or impediment. Thus cable tray and J-hooks would typically have to be close to 7' A.F.F. or higher in areas where the floor is accessible below.

Also consider whether segregating different classifcations of wiring as required by code or simply wanting to segregate signals/cable types or functions support using divided cable tray or multiple stacked levels of J-hooks.

The J-hook on the end of a pole that Derek suggested is one option to a ladder. Another trick, especially with undivided cable tray, is to bundle any cables that may be there for any length of time so that you aren't having to deal with picking individual cables out from those added.


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