# How to install conduit in concrete slab



## mthabault (Feb 24, 2010)

I am about ready to pour a slab for a new wood shop. I want to install a circuit of outlets in the floor. I am also installing a hydronic radiant floor heating system. The 4" slab is laid over 2" pink foam insulation. My questions are 1) is there a problem with installing the circuit in the slab with the radiant tubing (it will all be in 3/4 pvc conduit) and 2) can I lay the conduit directly on the insulation or does it have to be off the insulation and completely encased in concrete. The boxes require 3" in concrete and if I attach to the re-enforcing wire I will only have 2".


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## AllanJ (Nov 24, 2007)

My guess is that the conduit must be completely encased in concrete. Or rather the concrete surfaces, both top and bottom, must not have grooves running along them where pipes ran otherwise the concrete is subject to cracking along those lines.


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## Jim Port (Sep 21, 2007)

On commercial jobs the conduit is below the insulation and mesh reinforcement.


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## <*(((>< (Mar 6, 2009)

Jim Port said:


> On commercial jobs the conduit is below the insulation and mesh reinforcement.


x2, usually plumbing and electrical are ran before the sand base is put down under the slab.


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## J. V. (Jun 1, 2007)

Ty it down to the rebar or mesh. If your not using rebar or mesh, run it under everything. It does not need to be encased in concrete.

You are planning like a professional. Running conduit in the slab saves time, money and materials.
Make sure you do the same for the feeder coming from the panel. Stub it up for your sub panel inside. Nice and clean, no LB's. Same for any inside walls. Lay them out and stub up for receptacles, phone lines or CATV. Use the slab for as much as you can. If you use the slab correctly, you will need very little time and material after the structure is up.


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