# Laying the slab: wiring, conduit, etc



## John Simpson (May 10, 2007)

My thoughts have turned to the next stage of our build: the foundations and concrete slab.

Obviously all the plumbing drains need to be part of the slab, but what of the wiring? I've noticed a number of slabs with much of the electrical wiring buried inside as well, and wonder if that should be the case with conduits for speaker cables etc? Or is it safer to thread those through the timber frame once the walls are in place?

I'm guessing the slab wiring shouldn't be too complex, or there's a real risk of things going pear-shaped...


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## bpape (Sep 14, 2006)

If you have a choice, I'd never have any electrical in the slab. Just too many downsides with no (IMO) upside. Wait until you get things set the way you want them and PLAN for how you want to bring the service into each room.

Bryan


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## MatrixDweller (Jul 24, 2007)

Electrical code probably wouldn't permit bare cable in the slab. You would need conduit and it should probably run under the slab and not in it. It might then require a different type of insulator on the wire as well which could get expensive. As with any hole in a slab it would also introduce a weak point. 

Conduit can be nice and running it under the slab, or subfloor can save money as the wire can take the shortest path from the breaker box to the area. You can also save a few feet of speaker wire going under the floor as opposed to around the walls. Running 1/2" conduit though a 2x4 frame is a pain too, with lots of drilling. If it's under the slab though you'll have to be pretty exact about where you want it and there won't be any room for modification in the future.


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## Prof. (Oct 20, 2006)

I definately wouldn't put any wiring under the slab, even in conduit..
If the slab should settle further or you have a slight ground shift at some time, you could crack the conduit and get moisture or actual water into the conduit...Then you've got real problems..
Keep it all above ground level..


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