Electrical cable under Kitchen floor [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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01-09-2002, 03:06 PM
I removed terra cota tiles to apply ceramic tiles in the kitchen and found out that electrical cable was burried between the grout line hidden in metal conduit. I cannot do the same with the new tiles as they are thin and I cannot leave gap more than 1" between the tiles. Instead I decided to raise the concrete floor by about an inch so as to burry the cable conduit and tile above that. Am I on the right track or is there a better solution. What material should I use to raise the height of the floor? Your suggestions and advice will be much appreciated.

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01-09-2002, 04:35 PM
You would raise the floor with cement, but I would wonder if the tile would crack along the spot that the conduit ran through the cement, since this would act like a control joint(expansion joint). Can the wire be run along the walls, behind the baseboard?

John Bridge
01-09-2002, 04:55 PM

If you raise the floor that much, you won't be able to get your dishwasher out, and that's not good.

I would imagine the conduit goes to an island cabinet in the middle of the kitchen? Two possiblilies: Chop out a shallow rut in the slab and bury the conduit under the new tile; or eliminate the conduit if it only serves an outlet (do away with the outlet). If it runs a range or something important, go to plan A.

You can rent a small jack hammer that will make the work easy. Don't go any deeper than necessary.

01-10-2002, 09:25 AM
Thanks a lot for the advice. The cable actually runs a cooking range and hence is very heavy guage. Also since there are doors on both ends of the kitchen I really cannot re-run the cable behind base boards. John - the kitchen is in the second floor of a condo builiding can I still make a rut without causing any structural damage? Or raising the floor is the only option I have? Luckily the dishwasher has a clearance of about an inch from the counter top so raising the floor should not block it (but thanks for reminding cause I have not thought about that). Awaiting your expert advice once again - Many thanks in advance

01-10-2002, 04:23 PM
John, he would not actually be raising the floor that much, he would just be restoring the total height, wouldn't he? If the old tiles were thick enough to run conduit between the tiles and the new tiles are much thinner, you should not have a clearance problem even if you raise the base floor to a height nearly even with the conduit - all you would be doing is raising the level back to the same total height of the floor with the old (thicker) tile.

John Bridge
01-10-2002, 05:21 PM
Okay, condo, second floor. No, do not chop into the floor. It's not the same as a slab on the ground. It could be pre-cast or even "span-crete," which has hollows running through it. Let's not go there.

You might need to get hold of an electrician. We used to have one here, but he hasn't been around since he completed his tile project. :)

I think there must be a way to run the wires in a configuration with a lower profile than a round conduit, but I don't know what it is. What we have is two 10-gauge conductors and a bare (bond) wire. There should be a way to flatten them out somewhat, so that you don't have to go so high to clear them.

Where's Bud? Bud knows stuff like this. Where's Rob? Where's anybody? Help! :D

Bud Cline
01-10-2002, 06:02 PM
I wouldn't touch this with a ten foot conduit!

But seriously folks, I can't begin to imagine why it was done like this to begin with. I have never seen a case where a "wire run" couldn't be made thru the walls and ceiling in a residential structure.

Surely this circuit must begin at a panel. Why can't the run be fished thru the ceiling? Even if small access holes have to be cut in the sheetrock. Is there an attic access?

John Bridge
01-10-2002, 06:58 PM
Hey Bud,

If it's a range/stove island, there's no way to run the wiring down from the ceiling without it's being exposed. There's no wall to run it through. We're not talking about a peninsula.

I've seen it a lot on ground floor slabs. They usually bury a conduit before they pour and stub it up where the island cabinet is going to be.

spark chaser
01-10-2002, 07:53 PM
I have finished my tile project for now, but I still lurk on a regular basis.

The wire run is either #8 or #6 (probably #8,4 conductors) depending on how big his range/oven setup is. There are some specialty flat wire products that I have worked with in commercial buildings. Not my usual line of products, if I had a copy of "Graingers" on hand, I could probably give you some product names.

Such shallow running of this conduit does not sound like any acceptable method I have seen.

If I were in this fella's shoes, I would like to see original blue prints of the structure, and talk to a local elect. contractor experienced with commercial building remodels. A 40 or 50 amp circuit is one that really should be done correctly. They all should, but especially one that you are standing on.

I like the idea of cutting a trench and hammering it out to the proper depth, but this is where you need to know what you are cutting into, and how deep you can go without hurting the structure.

Bud Cline
01-10-2002, 08:42 PM
Island! Island? Island.

OK that's right, now I got it. Must have dozed off there for a decade or two.

Well then if that's the case, it just can't be done. There's another good reason not to ever have an island.

Sometimes I regret ever getting involved in any of this.

01-10-2002, 10:39 PM
Whatever happened to wood burning stoves?

Hman, are you keeping the island?

[Edited by flatfloor on 01-10-2002 at 11:45 PM]

01-11-2002, 12:08 AM
Hi Guys,

Curt here. The lowest profile "conduit" that you are going to find is a product called "wire mold". The site location is http://www.wiremold.com (what else would they call it?) As far as running the conduit with the tile, I wouldn't. I would go straight down thru the floor into the ceiling below , lay the conduit (emt or flex) and then come up thru the floor back to the island. It might take a bit of work, but it would be the safest way to do it. I don't know what part of the country you are from, but if you have the movement we have here in California, don't think of running the wires without a conduit. VERY DANGEROUS!! Is there any space between the finished 1st floor ceiling and the lower part of the 2nd sub floor? Wire mold is usually under an inch think. If that doesn't work, I'll have to have a few more details before I can come up with something else.

Hope that helps,


I'm, of course, working under the assumption that we're talking about an island here.

[Edited by Barbs on 01-11-2002 at 01:15 AM]

John Bridge
01-11-2002, 06:30 AM
Okay, now we're getting somewhere. Er, uh, where are we?

I'm glad you're hanging around, Spark. Join in once in a while so we can keep tabs on you. ;)

Curt, That's certainly the way to go if there's a space under the slab. I guess there has to be, though. He/she might not own the space, though.

01-11-2002, 07:36 AM
Guys, guys, guys, WHAT am I missing here?? With the exception of one or two people here who believe this wire should never have been done this way, you are all commenting on ways around the height of the conduit, but the overall height of the floor need not change. (Plus, I believe he said he has another inch to work with.)

The tile being removed was thicker than the conduit, as it ran between a grout line. The new tile is much thinner so there is clearance to lay a mud base thick enough to allow for the conduit. If the concrete will crack if the base is set around the conduit, set the base first and then cut a groove after it has set up sufficiently.

If the objection is running the electric under the tile at all (which I do not really understand, as that is how the mat floor heat works, but I am not an electrician), then there is certainly space above the ceiling in the room/condo below. That same floor mat does have a flat braided power lead, so perhaps that has a different rating, allowing for installation under a floor?


01-11-2002, 11:06 AM
Reading all the wonderful suggestions and advice I have come to the conclusion that I can raise the height of the floor. Any suggestions on what product is best to use? Thanks

John Bridge
01-11-2002, 03:51 PM

You didn't miss anything. We are just trying to avoid work (which is what we are all good at). Raising an entire floor because of an electrical wire has to be a last resort. That's all.


That much height is going to require cement mortar, unless you want to invest in flatfloor's self-leveling cement company.

01-11-2002, 05:15 PM
OK, here we go again, what are the dimensions of the room? BTW if you raise the floor in the kitchen what happens to the doorway transitions?

01-11-2002, 05:42 PM
The floor is only raising a little, if at all. It has to just clear the conduit, which was true before. It's just that the tile is thinner, so there's more under it. (Did I get that right?) I have enjoyed following this one.

John Bridge
01-11-2002, 05:53 PM
I'm guessing it's at least a half-inch conduit, which would be about 5/8 o.d. That's a lot of mud. And it might be a 3/4 in. conduit.

01-11-2002, 05:57 PM
Yes, a lot of mud, but not much additional height. Before, the mud was tile.

01-14-2002, 09:19 AM
I must say this is really an interesting and educating forum and also let me thank each and everyone of you who took the time to respond and participate. Your input was really valuable.

I already have raised the floor height by 3/4" with a pre-mixed concrete a product called Sakrete. The product gave me a pretty levelled surface. Then I used thin set to put the tile on top of the conduit. Well on the surface it looks good but I will know for sure once everything gets dried and folks start walking on it. I will keep you guys posted if this solution works and if you guys are interested. Thanks again

John Bridge
01-14-2002, 06:06 PM
Of course, we're interested. We put a lot of our limited brain power into this project. ;)

Did you bond the sack crete to the slab?

01-15-2002, 08:52 AM
Yes John I did.

Bud Cline
01-15-2002, 12:42 PM
........an island huh?

"Wull all bee damned"!

01-30-2002, 10:35 AM
As promised and for those who showed interest, the solution is working well the tiles are holding tight grout seems smooth. like they say "All is well that ends well"

Thanks again everyone. Keep up the good work

John Bridge
01-30-2002, 06:19 PM
The easiest, but most expensive, thing to use would be self-leveling cement, and you will be dealing with "da Leveler," Jim Buckley, alias flatfloor. Where are you Jim?

01-30-2002, 06:22 PM
John, I think he's saying he has the floor done.

Any word on my parole?

John Bridge
01-30-2002, 07:27 PM
Guess what. I was reading the final post on the FIRST page! Please tell me I'm not completely over the hill. I'm not even old enough to get Medicare yet. Help!

01-30-2002, 08:52 PM
I can get you medicare if you'll get me paroled, please boss.