Conduit depth in concrete

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rookie4now

Senior Member
We are setting a row of floor boxes in an existing slab. The GC saw cut the slab, we set the row of boxes and connected with 1" EMT. The inspector says that our EMT is not deep enough. That it must have 6" of cover??? I know on exterior there has to be 6-24" depending upon conditions, but I've never heard of this on an interior slab. What is the code reference on this? I can't imagine that all the highrises I see have no conduit that is less than 6" covered in concrete. Is the inspector correct that we need to cut the slab to a depth to allow 6" coverage?

Any code references appreciated.

Thanks
 

raider1

Senior Member
Staff member
Location
Logan, Utah
The burial depths in 300.5 do not apply to a raceway embedded in concrete.

There is no NEC requirement for required cover when embedding EMT in a concrete floor.

Chris
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
You can run the emt along the surface of the concrete floor if you want to, and not cover it with concrete at all, unless people drive forklifts in the area or there is some other reason to say it is subject to physical damage. There is no rule that gives a minimum concrete cover. If there were, it would likely be in either 300.4 or 358.12. It is in neither location.
 

rookie4now

Senior Member
The burial depths in 300.5 do not apply to a raceway embedded in concrete.

There is no NEC requirement for required cover when embedding EMT in a concrete floor.

Chris

When I told the inspector that 300.5 was for coverage when the conduit is buried BELOW the concrete, he asked me to show him the code section that refers to this situation. I could not cite a cde section that referred to conduit in the concrete so he said it has to be 6". I feel sure I'm right I just can't find a code section to show him. I do have a call into the Senior to discuss it with him.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
When I told the inspector that 300.5 was for coverage when the conduit is buried BELOW the concrete, he asked me to show him the code section that refers to this situation. I could not cite a cde section that referred to conduit in the concrete so he said it has to be 6". I feel sure I'm right I just can't find a code section to show him. I do have a call into the Senior to discuss it with him.

What part of underground doesn't the inspector understand? Embedded in concrete is not underground.


300.5 Underground Installations.
(A) Minimum Cover Requirements. Direct-buried cable or conduit or other raceways shall be installed to meet the minimum cover requirements of Table 300.5.
 
Provisions are included in the ACI 318 concrete code which is the IBC reference code and would cover most jurisdictions.

There are a number of requirements including min. 1.5" cover for conduits exposed to earth or weather, and 3/4" cover for concrete not exposed to weather or in contact with the ground.

Conduit should not be more than 1/3rd slab thickness.

Spaced no closer than 3 diameters on center.

This is a building code issue not an electrical code issue.
 

rookie4now

Senior Member
The senior inspector called back and approved it over the phone and said he would review it with the inspector. He didn't site a code either, he just said that the inspector misinterpreted the section and he would clarify it with him...Life is good again.

Thanks for the replies.
 

1793

Senior Member
Location
Louisville, Kentucky
Occupation
Inspector
The senior inspector called back and approved it over the phone and said he would review it with the inspector. He didn't site a code either, he just said that the inspector misinterpreted the section and he would clarify it with him...Life is good again.

Thanks for the replies.

Good for you and thanks for the update.
 
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