We are planning a kitchen re-do which will have an island as part of the design. What’s the proper method of getting power there, considering it’s a slab foundation? Existing room is being gutted to the studs so anything is possible. Thanks,
john
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Can we presume you will have a new flooring finish?
If so, then cut the slab for a conduit feed, then patch.
Yes, new floor will (probably) be engineered bamboo. Am I correct the conduit feed should be to same spec as new construction? Last time this was easy - house was on a crawl.john
Should not be a metal conduit, right?
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From under as Gene said... or wireless power feed?
Hopefully this isn't a radiant slab?
When you cut the channel for the non-metallic conduit, take a good look at the path for anything else that may be in there...water lines, other electrical runs, etc.
Smart idea and good to remember. The island will be directly between the kitchen sink and the bathrooms - those pipes are in there somewhere! I'll cut and lay PVC. Inspector gets to approve it like everything else we're doing. An electrician gets to run the wire when the 220 line is moved.john
Just finished a kitchen remodel in my house in So California...we put in an island on a slab foundation.
I cut the slab and trenched to the nearest partition (that's code). Fortunately, the drain didn't move much, so it was fairly easy to tie the new plumbing in, but the vent stack is totally different, obviously. Your building department should be able to give you a schematic of the vent layout, and you will need to tie that into the drain stack and route it to the partition and then up.
The electrical here needed to go through PVC conduit...metalic was not acceptable, as it would eventually fill with water (so will the PVC, but not as quickly I guess). I initially ran Romex through the conduit, but the inspector made me remove it and run individual wiring, and as I sit here I can't think of the designation of the wire...but it's waterproof.
Water supply went through the same wall and trench, copper sleeved with plastic. I also wrapped it with insulation.
A lotta stuff packed in that trench.
We did not change the tile floor, but fortunately I had a few boxes of extra floor tile in the garage.
Good luck...
The only way I can imagine getting the power there is to cut a trough across the slab with a diamond blade. If a 40 or 50a oven will be out there you'll need larger single-strand and will have to cut wider and deeper. Its doubtful you'll get down as far as rebar or other utilities. Put a fan in the window (surrounded by cardboard) so you don't trash the house with dust, as I've done royally several times.
Actually, a light spray on the blade with a garden hose lets your diamond blade last many times longer and then there's little dust, ya might not need the fan. Just have a dustpan and a bucket for scooping up the swill and make sure you're plugged into a GFI.
John,
In this situation, most people would use PVC conduit (Schedule 40 electrical conduit). EMT (thinwall steel conduit) is not approved for burial or encasement in concrete. An alternative to Sched 40 is IMC (intermediate metallic conduit, aka medium wall) or rigid metal conduit (RMC, aka heavywall). These require threaded fittings, and are a bear to bend. Use Sched 40.
As far as the wire, use copper wire with insulation type THHW or THWN. The "W" in each of those designations signifies that its suitable for wet locations. ANY underground conduit is considered a wet location. Even if subsurface moisture or water does not enter the pipe (slang for conduit), eventually moisture from the air will condense (underground temps being lower) and fill the conduit with water. Using duct seal (electrician's putty, aka "monkey sh1t") will slow down the exchange of air in the pipe, but you'll never be able to get a perfect seal.
I know it's hard to picture, but properly rated wire will work fine and not present any hazard even if it's sitting in water.
One other suggestion, if you're running AWG 6 or 8 conductors for an electric range, use copper, do not run aluminum. It will eventually break down in the mildly acidic water in the conduit.
As far as running NM cable in conduit--the 2005 NEC allows it, but it's not a good idea. The 2002 and earlier versions of the Code allow it only in certain limited circumstances. Some inspectors interpret this to mean no cable in conduit except for short lengths of sleeving for protection. And anyway, it'd be near impossible to pull 10-2 or bigger cable into a reasonable size conduit, if it has two 90 degree bends. For an electric oven, you may need two or three #8 (or #6) current-carrying conductors and a #10 grounding conductor. Forget trying to get that sort of cable through a conduit.
Good luck,
Cliff