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I'd like to install this (Manufc. Page) 20A GFCI pop-up electrical box in the kitchen floor to allow cookware (microwave, blender, air fryer) to be plugged in. I will build a kitchen island cart to house the microwave and store the other cookware.

I need to make a plunge cut for a hole through a 12"x12" 5/16"-thick ceramic tile and through the subfloor underneath to house the outlet and run a 20A line to the breaker box.

I have a wired Fein Multimaster oscillating tool but there isn't any literature on what blade to use to cut ceramic tile. I have an angle grinder, which I know could do the job, but the circular blade means I can't make a complete cut at a corner.

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    Kitchen floors often get wet. Wet electrical outlets can be hazardous. A pendant cord hanging from the ceiling might be a better way to have an outlet available at your cart location.
    – Ecnerwal
    Commented Aug 17, 2022 at 1:02
  • There should be no plugs in kitchen floor. What if someone mops the floor ?
    – Traveler
    Commented Aug 17, 2022 at 1:20
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    As for cutting, use diamond blade on slow speed with lots of water. The more cutting teeth on the blade the better.
    – Traveler
    Commented Aug 17, 2022 at 1:22
  • A carbide blade might cut through the tile, depending on the hardness. A diamond blade will certainly work. A segment blade gives you a fair bit of cutting length, but still allows you to work into corners.
    – HABO
    Commented Aug 17, 2022 at 18:20
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    @Ruskes your concerns are valid. For these reasons, I opted for a box design where the plug interface is raised above ground, tilted upwards at an angle and not recessed into the floor. It is GFCI protected and there is a gasket where the outlet shuts (the outlet itself is IP44 rated).
    – Minh Tran
    Commented Aug 17, 2022 at 19:22

1 Answer 1

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Drill the corners, Score & Break the sides

With a handheld "tile scoring tool" you can also score a rectangle after drilling the corners, and tap with a hammer to break up the tile within the rectangle.

Select a bit that is small enough so that the face plate covers the curve. Carefully tap away anything that remains, using a hammer and a mason chisel or maybe an old wood chisel.

Angle Grinder, Drill the corners

Or you can use the angle grinder for round or rectangular holes, as you stated. Since you don't have access to both faces of the tile, you will have over/under cut. As with the score & tap approach, the trick is to drill the corners.

Hole Saw for wire only

For a round hole you can use a "Tile Hole Saw" for this:

enter image description here

This would allow passage of the wire. The outlet could then be on a raised box, with a cover or faced sideways, to prevent liquids from flowing in. This is especially important if it is located in the "wet area" of the kitchen: near sinks, stove, and dishwasher, within reasonable flooding area. If it is not in a tripping area you could raise it even just by 0.5 inch.

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  • I love my oscillating saw, but it is not the right tool for every job.
    – FreeMan
    Commented Aug 18, 2022 at 13:36

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