Existing Duct Bank Considerations

[Desert Sparky]

Planning for an expansion to an existing building, our surveyor has indicated there is an existing electrical duct bank routed underground exactly where the new expansion will sit. Generally speaking, is there any code issues with building over an existing duct bank assuming it does not interfere with any of the new footings? I could not find any NEC reference that discourages this scenario. Thoughts?

 

[ron]

If we were to guess that the ductbank was originally compliant with NEC Table 300.5(A), then the requirements under the building are less than if it were under roadways or grass.
If the Neher McGrath calculations from the previous install are available, just be sure they didn't count on an special thermal resistivity of the surrounding materials that would be disturbed by the building.