Trench-duct

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kbsparky

kbsparky

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Location
Delmarva, USA
I have a customer who is building a new manufacturing/assembly building.

He wants some sort of "floor duct" to install in several straight runs from the back wall and then out 40 feet. This stuff would be maybe 4x4 inches, with a flush mount cover on top that could withstand a forklift running over it. The cover would be removable in sections along its entire length.

He plans to have us install complete cable assemblies in there (such as MC or TC cable), and have them emerge at appropriate locations to power his equipment. This system would allow him to expand or relocate equipment easily, without having to cut the floor up each time they do such a thing. They do NOT want any "ceiling drops" as the roof is over 25 feet up.

We are looking to install maybe 200 feet of the stuff (5 runs x 40 foot).

When I inquired at the local supply house, they quoted me some Wiremold stuff that costs over a hundred dollars a foot! (Over $21,000 for the lot)

Now, this is way more than I had expected it would be, so before I submit my proposal to the owner, I want to know if any of you here have had experience with this type of product, and what it's approximate cost should be.

Any sources out there?
 
Although there may be others, Walker Duct has been an industry standard for years. They're owned by the Wiremold company. Given their large market share I'm not surprised at the premium price.
 
Is there a reason the concrete contractor can't just box you out a trough in the floor whatever size you need? Have a stepped ledge at the top for laying a piece of sheet steel flush with the top of the concrete. One of the definitions of raceway is "underfloor raceway," but maybe this is stretching it.

I know the company I work for once made a concrete trough under some MCC sections. Pipes were just stubbed into the trough and THHN was ran free air. Where the MCC didn't cover, they just layed aluminum diamondplate on top of it.
 
We would not be installing any "Free air" THHN conductors, however the installation of concrete forms sounds intriguing. From other sources it would appear that $100 or so per linear foot is about right for this type of product.
 
I'm wondering if you can run a "trench drain" and then run conduit inside that. It would have a perforated top, so you might have to use a liquidtight wiring method inside it. But there wouldn't be any problem with trucks running over the top of it.

Steve
 
I had a chat with the building owner this morning about this aspect of the project.

In their existing facility, they merely rented a concrete saw, cut out a trench. They lined the trench with steel plates, and covered the whole thing with removable steel covers. And a whole lot cheaper than the $100/foot starting price we have been quoted for the materials alone.

He will contact the builders, and have some carpenters build a plywood "box" to pour around. Once the cement is hardened, they will probably line the trench with something like a standard Hoffman wireway. As long as a sufficient flange is left to hold the thick steel plates for the covers, Again, much less expensive, and it should get the job done.

I figure for over $100 a linear foot, I should be able to get a complete buss duct, with 3 phase conductors installed! :mad:
 
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