1 Calories Burned For Walking: 3.15 mph (19 minutes per mile). 2  Calories Burned For Walking: 2.85 mph (21 minutes per mile). 3  Calories Burned For Treadmill: 5 mph (12 minutes per mile).4  Calories Burned For Treadmill: 5.45 mph (11 minutes per mile). Calories Burned For Walking: 3.15 mph (19 minutes per mile). 2  Calories Burned For Walking: 2.85 mph (21 minutes per mile). 3  Calories Burned For Treadmill: 5 mph (12 minutes per mile). 4  Calories Burned For Treadmill: 5.45 mph (11 minutes per mile).
Direct Burial of Cables or Conductors. Underground feeder cables, labeled UF, can be buried without additional protection from conduits because they have a tough jacket designed for burial. Bury UF cables 24 inches below the soil surface, and 18 inches deep when protected by 2 inches of concrete. For all other applications, the burial depth is the same as specified for conduits, except that conduits are required for UF cables in 2 inches of solid rock.
I just finished digging a thirty foot three foot deep trench. It took me four and a half hours and I was working in rocky clay. A pick and good shovel are nessesary. You are going to have to dig it 12 to 16 inches wide to have enough room to stand in it as you dig. Watch out for buried pipes and wires.