Conduit installation in an existing site

[jjmeggo]

Hello all. This is my first post to the site but I am an continous reader.
I have a project at an existing container port that is using deisel powered stratal carriers. The container handler is converting to electric rubber tire gantry (ERTG) machinces in order to go green. The container yard was built before 2000 and the entire container yard is 3 inches of pavement over 16.5 inches of rolled compacted concrete. See the diagram. The detail shows 3 inches of asphalt surface covering 16.5 inches of roller compacted concrete, 6 inches of aggregate course base, 4 inches of #78 stone drainage, geotextile fabric and type 1 select fill material. My question to the group is, can a row of 4 inch electrical pvc conduit be installed on the 4 inch #78 stone drainage layer and covered with approx. 18 inch of concrete and then paved over with the 3 inches of asphalt surface material. The voltage will be 6.9kV. The civil engineer would like for the electrical installation be above the geotextile fabric and drainage layer.

Thanks for and advise in advance

 

[ron]

What is the criteria from 300.50?

What is above?

 

[jjmeggo]

The asphalt is the finished grade which will be for heavy load traffic in an industrial park. This is a container port and the area is for storing 40ft shipping containers. The conduit installation will not be under any storage area but will be in the drive lanes.

NEC 300.50 column states 24in but general note 3 states for 2 inch of concrete above can decrease the depth by 6 inch. This will be covered with 18 inch of concrete plus 3 inch of asphalt surface.

 

[ron]

The asphalt is the finished grade which will be for heavy load traffic in an industrial park. This is a container port and the area is for storing 40ft shipping containers. The conduit installation will not be under any storage area but will be in the drive lanes.

NEC 300.50 column states 24in but general note 3 states for 2 inch of concrete above can decrease the depth by 6 inch. This will be covered with 18 inch of concrete plus 3 inch of asphalt surface.

Only you and the AHJ can decide if the heavy load traffic in an industrial park is considered industrial AND that maintenance and supervision ensure that qualified persons will service the installation. Often it is industrial, but also often nobody wants to guarantee that the maintenance and supervision ensure that qualified persons will service the installation. "Hey Bobby, get of that forklift and reclose that breaker thingy."

 

[jjmeggo]

I understand where you are comming from and I will get with the local AHJ. The facility is a guarded and gated facility with deticated maintance personnel. The electrical building are locked and only maintance personnel have access. This is a TWIC facility. Again thanks