250ft from main panel in house to greenhouse out back. Greenhouse will have propane heater and one 120v outlet.
Today I dug 100 ft trench to the house 1ft deep. I put 1" and 3/4" conduit in the trench along with a 12AWG THWN solid copper wire (tracer). The 1" conduit will have a MDPE gas line, the 3/4" conduit will have THWN wire. I know MDPE can be direct burial but I like the idea of having it in 1" conduit just in-case.
I'm running 4 THWN conductors 10AWG. At the house, 10-3 NM-B will splice to the THWN in the LB as it exits the house. In the greenhouse I have a small outdoor rated 70A subpanel; 2 circuits.
1) Do I need a grounding rod at the sub panel? I know it should NOT get tied to neutral.
I will install 30A GFCI breaker in main panel, 1 pole or 2?
3) Can I install two 15A breakers in sub panel, each would be 120V?
The breakers in sub panel can be non-GFCI, correct?
Edit - Update
Trench is 18" now, my back is out also!
I will make sure the LB I use is labeled with volume calc.
I changed to a 30A 2 pole non-GFCI in main panel; then put the GFCI's in the sub panel. I'm hoping this would cut down on nuisance GFCI trips.
HomeDep0t won't take back my 10AWG custom cut THHN wire, I really want to switch to 8AWG for voltage drop. But the subpanel circuits will have very light loads so if I can't find a buyer for the 10AWG, then that's what I'll use.
Can someone review the connections in pic? This is Square D 70A Homeline Outdoor Load Center. I added the wiring diagram to the pic.