old folks community with 1 story (no basement) units built on 7 inch concrete slabs...prior to roughwire the builders staff was laying a pvc pipe for us to run a wire for the kitchen island outlets, dw, disp, etc...it has now come to my attention (85 +- units later) the pvc pipe is directly on top of the stone in the concrete as opposed to in the dirt underneath the the stone and concrete...i always thought the pvc had to go in the dirt...builder said building inspector said he had no problems...electrical inspector either missed it or is ok with it as is...should i tell the builder he must now put pipe in dirt?...
wire encased in pvc in concrete slab
- Thread starter rodneee
- Start date
- Status
- Location
- Massachusetts
There is no NEC requirement for it to be in the dirt, that is often a job specification.
sandking
Member
- Location
- Southern California
Yep, what he ^^ said. Although it is legal to be in the middle of a slab (like a wall in a tilt up building), its best to get it below the grade just in case there might be some other saw cutting going on in the area years down the road, but if its done already, I would not look back 
- Location
- Simi Valley, CA
4" of concrete cover is all that is required. Many are mistaken that it's supposed to be down 4" in the dirt, before you pour the concrete.
- Location
- Massachusetts
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
I am going with 0" required.
Maybe, I found this in the IBC.
1906.3 Conduits and pipes embedded in concrete. Conduits, pipes and sleeves of any material not harmful to concrete and within the limitations of ACI 318, Section 6.3, are permitted to be embedded in concrete with approval of the registered design professional.
- Location
- Simi Valley, CA
I am going with 0" required.
Which part are you going 0" with?
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I would guess the depth of the concrete covering the pipe.
- Location
- Massachusetts
Under a building is 0"
If we try to apply the 4" concrete rule to wiring in the ground level slab of a building we can't enter many floor boxes or use Walker Duct with 2" cups.
Actually, IMO nothing in table 300.5 applies to conduits 'in' slabs.
That table is for underground raceways and cables.
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DaveBowden
Senior Member
- Location
- St Petersburg FL
Assuming these slabs are directly on the ground, I don't think you'll be able to use romex to wire any of your outlets in the islands.
- Location
- Simi Valley, CA
Oh in that case you are correct. :happyyes:
Volta
Senior Member
- Location
- Columbus, Ohio
Well, I would consider "under" to be different from "within", but you know me. :roll:
Eh, Note 3 would probably cover that one.
That I can go with though.
- Location
- Massachusetts
And I would consider a conduit laying on the dirt under the lower level slab (as the OP describes) to be under the building not within the the building.
Or is there some other location where we would have 0" of cover over a raceway and is under a building?
Volta
Senior Member
- Location
- Columbus, Ohio
Yeah, me too. In rereading I guess I mistook your post in response to
to mean that even is still within the slab, 4" below the top was under the building. But it didn't.
Maybe, but having nothing to do with these scenarios.
- Status