Burial wire for low voltage circuit in tile floor?

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markebenson

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I don't know if this can be done or not. The idea is to cut out the 3/8 grout line in existing floor tile, lay some type of burial wire 4" deep and then grout back over it. The voltage is negotiable. I prefer 24vac. The length of the trench about 16ft. Current is about 5a. The purpose is to power pool tables. In the photo shown this is my last job but we ran 110v in conduit before the tile was laid. I am looking for a solution for when there is existing tile.
 

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Will Low voltage work for the pool table operation? If so, I wouldn't run any "normal" voltage wiring in such a scenario as "someone" later will see a 12 or 14 wire and say "hey let's use this wire" such as UF cable. UF can be used as low voltage class 2 or 3. But, UF is not allowed embedded in concreted anyway, 340.12(8).

My Question would be Who goofed? If power was going to be needed at the pool tables why wasn't it run before the tile guys came?
4" is kind of deep to cut into a grout line between tiles. Even if Low voltage cable was used it still would require some sort of protection as it enters and exits the floor.
Only wiring that I'm aware of that comes close to meeting specs for low voltage direct concrete encasement would seem to be PLTC-ER type cable. But smallest I've found was the 20awg 8 pairs and still over 1/2" diameter.

Pop tiles up, cut trench in concrete, run raceway, and wire up. Then refill with concrete and tile. Owner may not like the option but if they want power to the pool tables, 🤷‍♂️.
 
Maybe you can go under the sub floor. If it is just concrete on dirt, you should be able to push a pipe underground and get a passage to where the power is needed then just pop up through the tile.

Whatever ends up being done is not you doing it though. Someone with tile repair skills is in order.
 
What about some sort of low volt landscape lighting wire. I don’t know that it will be “grout rated” but the outer jacket is pretty thick, but not too thick if you take the time to stack it in the grout line on edge if that makes sense.
 
Fred B said:
Will Low voltage work for the pool table operation? If so, I wouldn't run any "normal" voltage wiring in such a scenario as "someone" later will see a 12 or 14 wire and say "hey let's use this wire" such as UF cable. UF can be used as low voltage class 2 or 3. But, UF is not allowed embedded in concreted anyway, 340.12(8).

My Question would be Who goofed? If power was going to be needed at the pool tables why wasn't it run before the tile guys came?
4" is kind of deep to cut into a grout line between tiles. Even if Low voltage cable was used it still would require some sort of protection as it enters and exits the floor.
Only wiring that I'm aware of that comes close to meeting specs for low voltage direct concrete encasement would seem to be PLTC-ER type cable. But smallest I've found was the 20awg 8 pairs and still over 1/2" diameter.

Pop tiles up, cut trench in concrete, run raceway, and wire up. Then refill with concrete and tile. Owner may not like the option but if they want power to the pool tables, 🤷‍♂️.
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i feel the same way providing they can get new tile to match
 
LarryFine said:
But can't it be placed in a cut and, say, caulked over?
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This is what I was thinking too. Assuming UF is permitted based on the building type. You could use sanded caulk that color matches the grout or you could caulk the UF down low in the "trench" and grout over the top.

How deep would you need to go if it's 120v but still inside a building?
 
LarryFine said:
But can't it be placed in a cut and, say, caulked over?
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If you want to play this stretch with UF, then you must then still meet 300.5 requirements. Placing it "under" the concrete, and meet either column 1,4,or 5, and even then still provide protection as it enters and emerges from the concrete.

marmathsen said:
How deep would you need to go if it's 120v but still inside a building?
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300.5 Only allowed conditionally "Under a building" of 0" depth is in a raceway, MC or MI Cable listed for direct bury. Does not list UF cable under this condition.
 
Fred B said:
If you want to play this stretch with UF, then you must then still meet 300.5 requirements. Placing it "under" the concrete, and meet either column 1,4,or 5, and even then still provide protection as it enters and emerges from the concrete.


300.5 Only allowed conditionally "Under a building" of 0" depth is in a raceway, MC or MI Cable listed for direct bury. Does not list UF cable under this condition.
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300.5 does not apply to a chase cut into a floor. The title of 300.5 is Underground Installations.
 
infinity said:
300.5 does not apply to a chase cut into a floor. The title of 300.5 is Underground Installations.
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No Definition of "Chase" in code. Only reference in code to an allowance of a "chase" is a reference in 334.10(B)(3) for NM-C type wiring but shall be covered by 1/16" steel metal plate. 334.15 requires NM-C to be protected from damage and references 300.4(F) requirement that is similar to 334.10.
340.10(4) has by reference the same requirements for UF as above for the NM-C.

Before the argument of the floor will not have Nails or screws, there is no exception or difference referenced for a floor "chase" vs a wall "chase".
 
kwired said:
Overall jacket diameter is well over the 3/8 mentioned in OP. Just something to take into consideration.
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Yea i think so. I used to do tile work and tge grout lines are often too narrow but as far as depth, doesnt low voltage arrigation similarly allow wires to be burried higher to the ground surface tgan normal?
 
Jpflex said:
Yea i think so. I used to do tile work and tge grout lines are often too narrow but as far as depth, doesnt low voltage arrigation similarly allow wires to be burried higher to the ground surface tgan normal?
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Yes but these wires are not being buried in the ground.
 
I don't see any simple solution here. Someone is going to have to tell the owner the bad news and the options and let him decide how much money he wants to spend. I still think my previous idea of drilling thru the tile and concrete into the dirt below and just boring over to that hole is the simplest and cheapest. The hole in the tile can be covered by a floor box for a receptacle.
 
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