Floor Boxes/Duct

[jmellc]

A customer may soon want a floor box at a desk out in the open. GC is worried about cutting prestressed concrete floor. Does anyone know of a very shallow box/duct that can be cut into concrete floor?

 

[infinity]

Is there access from below, can these slabs be core drilled for a poke through?

 

[jmellc]

Slab on ground. GC says no way to cut all the way down. NEC mentions duct/boxes level w/ surface, so I assume they exist.

 

[infinity]

The raceway can be in a shallow chase, if you used 1/2" EMT you would only need about a 1" channel in the slab. The box would be a little different because floor boxes are generally a few inches deep. If it's a slab on grade is there really an issue with a narrow chase and chopping in a box?

 

[jmellc]

GC worries about cutting a stressed cable or rod, causing damage.

 

[infinity]

You can have the slab X-rayed first to ensure that nothing will be damaged.

 

[norcal]

If the location is allowed by the NEC, what about flat cable under carpet squares?

 

[jmellc]

If the location is allowed by the NEC, what about flat cable under carpet squares?

They have now decided against the floor box altogether but I will check out the flat cable idea just in case and/or for similar situations. Do you know a good brand?

 

[jmellc]

You can have the slab X-rayed first to ensure that nothing will be damaged.

I suggested this to the GC. He does not trust X rays. Said he paid a fortune for x rays awhile back. The guy scanned and marked a route. He cut trench and hit a water line the guy didn't see.

 

[don_resqcapt19]

I don't think I have ever seen a pre or post tensioned slab on grade. I guess with poor soil conditions, it could be more cost effective than all of the digging, back filling and compaction that would be required to make the soil suitable to support the slab.

 

[wwhitney]

I don't think I have ever seen a pre or post tensioned slab on grade. I guess with poor soil conditions, it could be more cost effective than all of the digging, back filling and compaction that would be required to make the soil suitable to support the slab.

Yes, it is common in areas with expansive soils to use a post-tensioned slab on grade.

Cheers, Wayne