Cutting hole in slab for electrical outlet


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Old 08-24-18, 12:57 PM
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Cutting hole in slab for electrical outlet

We are changing out our kitchen island for a stand alone/moveable island. The previous island had electrical running through it and we would like to switch to a floor outlet since the new island will be mobile. Our kitchen reno is due to a house flood from a plumbing issue so we currently have no flooring and just bare concrete. The line is already running through the concrete slab so we won't have to dig a trench or anything. Can anyone suggest the best way to cut out the square to install the outlet box?
 
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Old 08-24-18, 01:05 PM
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I'd use a concrete hole saw to cut a round hole for a round floor box.
 
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Old 08-24-18, 02:10 PM
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Hi, as mentioned a concrete core bit, larger than the box and a bit away from the current location to allow for a short extension of existing feed, plan on patching around everything, post a pic of the current situation.
Geo
 
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Old 08-24-18, 03:07 PM
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Is your existing cable in a conduit? It should be if it was feed under the slab.

You will have to breaker concrete around the conduit, cut the conduit shorter and install a junction box under in the concrete.

Concrete core bit is expensive to purchase for a single use. Check with your local tool rental shop. Some rents core bits. You will also need a SDS Max hammer drill.

If you want to go cheaper, you can get away with a grinder with diamond blade. Cut around the conduit with grinder. The cut should be at least 1/4" to 1/2" lager than the junction box you are installing so you can set the junction box with cement. Will have to cut 1" to 1 1/2" deeper than the junction box to install conduit connector.
The best way to cut the conduit with wire still inside is using a tubing cutter. Midget tubing cutter will be the best for small space.
If you have a metal conduit, you need to deburr the cut.
 
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Old 08-24-18, 08:49 PM
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I'm not sure why we never thought about the round floor box as an option! Thanks!
 
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Old 08-24-18, 08:54 PM
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Yes, it is in a conduit. The great internet suggested renting the concrete core bit, but I haven't had a second to run that option down yet. My first thought was the angle grinder with diamond blade. Thank you so much for all of the other info!
 
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Old 08-25-18, 07:53 AM
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Make sure the box is rated for concrete floor, there are many options out there, I would go with a complete unit with receptacle and cover to match.
Geo
 
 

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