Comments 1 - 8 of 8 Search these comments
If I dig the trench 4 inches wide at a depth of 14 inches (12 inch depth + 2 inches for conduit)
install a 240V Mini Split, they are more efficient and cool much better than a 120V Mini Split.
On further thought, I would not encase the pipes in concrete. If the concrete settles and cracks it will crack the pipe along with it. Then your wires will be exposed to the dirt and water
I've asked a couple of local licensed electricans' and have not gotten a decisive answer (meaning I have not gotten the answer I wanted).
I am going to be running power from the main house circuit panel to an out building with a run of approximately 150 feet.
My question involves the burial depth for 2 inch conduit with THHN conductors to support a 40 or 50 A service to a subpanel in the out building.
Because the burial involves going through clay soil and through a dead tree root system I would like to keep it as shallow as code allows. I do not want to deal with metallic conductor because PITA. I do not want to deal with direct burial cable because PITA. I want THHN in plastic conduit because NPITA.
By my interpretation that means I'm looking at column Column 3 of table 300.5 : "non-metallic raceways etc..."
My question is this : If I dig the trench 4 inches wide at a depth of 14 inches (12 inch depth + 2 inches for conduit) and then fill it in with bags of Quickrete do I meet the requirements as stated in column 3, row 2 which states " In trench below 50mm (2 in.) thick concrete or equivalent" ? My local elec's are telling me to dig it to 20 inches but without addressing what is in the table itself - because no one has asked them about filling the trench with cement before so they aren't sure.
TIA.