Finding electrical wiring in concrete

[Jubee]

Helping a friend restore his condo and one massive wall has a lot of outlets and we've tried to find the electrical wiring.
None of the Home Depot stud finders which claim to find electrical can find any of it. I'm out of ideas, I have to assume the only way would be with x-ray?? Which itself is wild and probably stupid expensive, anyone have any ideas or suggestions?

 

[Ceiling Cat]

Maybe a stud finder is not the best tool for the job. You need a dedicated device designed to trace electrical wiring.

 

[gar]

Don't really understand why you're trying to find the electrical wire. The wires which are buried in concrete are run through a plastic pipe/conduit. The conduit is installed before the concrete is poured and then wires are run through the pipe. You're allowed 12 general use outlets per circuit, so the outlets on the wall are probably all connected to each other. So the only way to access the wire is through the existing receptacles, switches and lights.

 

[Jubee]

Don't really understand why you're trying to find the electrical wire. The wires which are buried in concrete are run through a plastic pipe/conduit. The conduit is installed before the concrete is poured and then wires are run through the pipe. You're allowed 12 general use outlets per circuit, so the outlets on the wall are probably all connected to each other. So the only way to access the wire is through the existing receptacles, switches and lights.

He wants to drill some serious heavy duty cabinets through a wall. We're talking long TapCons and/or anchors, not sure yet, so he wants to avoid hitting any conduit when pre-drilling.

 

[SchlongConery]

Couple of thoughts.

Ceiling Cat knows about finding wires in walls! That Device he shows you is a common electrician’s tool. However, as somebody else has said, those wires will be enclosed conduit that is buried at least 2 inches deep in the concrete. So the buzz box might not pick up the signal.

Tapcon’s can hold a lot of weight in shear loading. The smallest Tapcon is 3/16 x1” and EACH fastener will hold 720lbs in 13 MPa concrete. I don’t think there is any part of a high-rise building that uses anything less than 30 MPa Concrete.

Have a look at this chart for actual specs. Take into account that they also have already included safety factor

Technical Specifications for Tapcon® Concrete Screws

Tapcon Concrete Screw technical specifications and information. Holding values, size range, Material Specifications and values.

www.confast.com

I would suggest using the 3/16“ x 1 1/2“ hex head Tapcon screws with a good drillbit. Don’t overtighten them.

They will absolutely hold anything he wants to hang off them.

last thing I’ll mention is for your friend to be very careful about drilling into structural walls in a condo. The Declaration always make it very clear that the structural walls do not belong to the owner, they are common element and are not supposed to drill / cut, etc.. I know of somebody who drilled a wall full of wire shelving with big long tapcons and the neighbour complained. After the owners belligerence (cluelessly) yipping about his rights and the subsequent lawyers letters, Engineer Reports and repairs..,it cost the guy over 10 grand!

The proper way to go about these projects is to get permission from the corporation before starting. That way, whatever you do has already been approved and it won’t come back to bite you in the ass.

 

[gar]

He wants to drill some serious heavy duty cabinets through a wall. We're talking long TapCons and/or anchors, not sure yet, so he wants to avoid hitting any conduit when pre-drilling.

Since the conduit travels in basically straight lines, the conduit runs straight up vertically from the receptacle to the ceiling so you should avoid drilling there, obviously the farther away from this spot is better. If it runs horizontally to the other outlets, you don't have to worry because they're lower than you'll want to attach the cabinets.
The 2 most likely receptacle boxes which would have a vertical conduit are either A) the closet receptacle to the panel box or B) the closest receptacle to the fixture on the ceiling. Hope this helps

 

[SchlongConery]

Since the conduit travels in basically straight lines, the conduit runs straight up vertically from the receptacle to the ceiling so you should avoid drilling there, obviously the farther away from this spot is better. If it runs horizontally to the other outlets, you don't have to worry because they're lower than you'll want to attach the cabinets.
The 2 most likely receptacle boxes which would have a vertical conduit are either A) the closet receptacle to the panel box or B) the closest receptacle to the fixture on the ceiling. Hope this helps

If it is a typical concrete condo, the wires that service that suite will come up from the slab, not down. Except in areas where there is a dropped ceiling.

 

[gar]

If it is a typical concrete condo, the wires that service that suite will come up from the slab, not down. Except in areas where there is a dropped ceiling.

Not the case in my condo. The wires are run up from the panel box to the extra deep junction boxes in the ceiling. This allows multiple branch circuits to be serviced by one junction box. The multiply circuits can then be routed to where they're needed. It's more practical, you use less materials, labour and time by using junction boxes to run multiple circuits instead of dedicated lines for each branch circuit.
If the wires were run up from the slab, my junction box in the ceiling would only have one pair of wires not multiple pairs.

 

[HotDogger]

Couple of thoughts.

Ceiling Cat knows about finding wires in walls! That Device he shows you is a common electrician’s tool. However, as somebody else has said, those wires will be enclosed conduit that is buried at least 2 inches deep in the concrete. So the buzz box might not pick up the signal.

Tapcon’s can hold a lot of weight in shear loading. The smallest Tapcon is 3/16 x1” and EACH fastener will hold 720lbs in 13 MPa concrete. I don’t think there is any part of a high-rise building that uses anything less than 30 MPa Concrete.

Have a look at this chart for actual specs. Take into account that they also have already included safety factor

Technical Specifications for Tapcon® Concrete Screws

Tapcon Concrete Screw technical specifications and information. Holding values, size range, Material Specifications and values.

www.confast.com

I would suggest using the 3/16“ x 1 1/2“ hex head Tapcon screws with a good drillbit. Don’t overtighten them.

They will absolutely hold anything he wants to hang off them.

last thing I’ll mention is for your friend to be very careful about drilling into structural walls in a condo. The Declaration always make it very clear that the structural walls do not belong to the owner, they are common element and are not supposed to drill / cut, etc.. I know of somebody who drilled a wall full of wire shelving with big long tapcons and the neighbour complained. After the owners belligerence (cluelessly) yipping about his rights and the subsequent lawyers letters, Engineer Reports and repairs..,it cost the guy over 10 grand!

The proper way to go about these projects is to get permission from the corporation before starting. That way, whatever you do has already been approved and it won’t come back to bite you in the ass.

Excellent advice but I’d go with the 1/4” X 1 1/2” tapcons. They have better holding power (less problematic with overtightening) and more shear strength. They are my goto bore diameter when fastening into concrete or brick. Hex heads are the best. Just don’t set your torque settings too high when screwing them in.