I've been searching for information on how to bring electrical service underground to a shed that will be sitting on a concrete slab 12" thick at the perimeter. The shed will sit about 6" in from the edge of the slab. There is plenty of information available on how to run underground conduits but I'm specifically interested in how the conduit passes through the concrete slab so that it is code-compliant (US Uniform Code) and how to prepare for this before the concrete is poured.
Electrical Metallic Tubing can be buried 6" deep. Can EMT that has been bent into an L exit the face of the slab and connect there to EMT coming from the house, and emerge from the slab inside the shed just beyond the sill plate? Or does the EMT have to emerge outside the shed and connect there to a box and from that box pass through the wall of the shed?
Best Answer
If you decide to use EMT in ground it will need to be buried 18” per NEC table 300.5.
You can bring the EMT up through the slab and bottom plate if you want . I bring conduit into buildings this way quite often. Make sure to allow for your disconnect many jurisdictions require it on the exterior of the structure. You can bring the conduit up just outside the structure.
EMT coming through concrete is ok per NEC 358.10.B.1
My recommendation would be to run pvc underground and schedule 80 when you come up through the slab if not inside a wall, inside a wall schedule 40. why pvc? Emt even though it is galvanized will rust out and EMT / concrete / earth although allowed sets up the ideal conditions to rust out so it will not last as long as PVC. I have had rigid that I installed rust out but I have been doing this since the 70’s.