wiring under a concrete patio?


Old 05-08-07, 07:43 PM
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Join Date: May 2007
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Question wiring under a concrete patio?

I'd like to know the best way to run wire under a concrete patio for any future need to different points around or beyond the patio. Are there any special requirements of how much concrete has to cover it? Do I use conduit and just cap each end at the edge of the concrete, or elbow it up to the surface? Should I lay several separate wires &/or pipes to different locations? Can a gas line also be pulled through conduit if we should want access to that in the future?
Thanks for any and all help........Brenda
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Old 05-08-07, 09:01 PM
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Almost all of those things are possible. What you do depends on what future possibilities you want to plan for. And predicting the future can get pretty difficult, and allowing for all possible futures can get pretty expensive.

You only need to go 4" under the slab, assuming the slab will see no vehicular traffic and that it is at least 4" thick and the conduit is at least 6" from the edge. I suggest you use PVC conduit of a size somewhat larger than you think you need.

Don't run gas and electric in the same conduit. You don't need to elbow it up to the surface since you can always do that later. Cap the ends just to keep the dirt out.
Old 05-09-07, 05:13 AM
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As John mentioned, the 4" depth is necessary. I had to diagnose a row of sidewalk lights on concrete piers going down to a waterside dock. I found the original "electrician", or person in charge of installing the lights laid the underground feeder in the path of the steps/walkway, and allowed a pour directly on top of it. After about 3 months the concrete naturally shifted slightly, and the UF cable, naturally, broke. Necessitated rewiring in conduit buried along side the sidewalk. If it had been done properly, there would have been no problem.
Old 05-14-07, 08:10 PM
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Join Date: May 2007
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Smile Thanks....

Thanks so much for all the advice. We ended up running the wire around the patio, instead of under it, and that seems to have worked well.
We appreciate the input.............Brenda
Old 05-15-07, 10:01 AM
Join Date: Sep 2000
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You didn't ask, and it's probably too late, but the depth requirements are considerably stricter for going around rather than under. Depending on what kind of circuits you might put in that conduit, you'd be required to go either 12 or 18 inches deep. If you haven't filled in the trench yet, dig deeper. In certain situations (probably not yours), you'd be required to go 24 inches deep.

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