concrete encased PVC conduit duct banks and Table 300.5 (0-1000V)

[mshields]

What is the minimum cover requirement for PVC encased in concrete ductbanks and why is this very common construct seemingly not included in Table 300.5?

Thanks,

Mike

 

[don_resqcapt19]

Concrete encasement does not change the required burial depth.

 

[Julius Right]

In my opinion, the minimum backfill cover for a concrete duct bank will be as per Table 300.50
column 2 and a minimum 2? concrete it is required above the conduit [see b note].The duct bank shown in Figure 310.60 is provided with 3.5? concrete above the conduit [if the duct size will be 4? only].The minimum concrete thickness between ducts has to be 3? in order to assure
the required mechanical strength.

 

[don_resqcapt19]

In my opinion, the minimum backfill cover for a concrete duct bank will be as per Table 300.50
column 2 and a minimum 2? concrete it is required above the conduit [see b note].The duct bank shown in Figure 310.60 is provided with 3.5? concrete above the conduit [if the duct size will be 4? only].The minimum concrete thickness between ducts has to be 3? in order to assure
the required mechanical strength.

The concrete encasement in note "b" only applies where the raceway is not listed for direct burial without concrete encasement. Most of the non-metallic raceways that we install are listed for direct burial without concrete encasement, and the use of the concrete encasement is a design issue, not a code requirement.