- Location
- Massachusetts
I only set my "tube" about 6" below grade. This allows the concrete to be poured into the hole, not into a tube in a hole. This way it is stable. You don't have to rely on the backfill around the tube to hold your pole base stable. Not to mention that the conduits enter the pole base well below the bottom of the tube. for a base that is 6' tall (4' in the ground 2' above ground) the tube is cut 30" long.
In my opinion you are over thinking it.
The company I work for does 100s of site poles a year, the majority of them are installed on precast bases that have been lowered into the hole. They do not tip over.
I think that we may be forgetting that 6000-8000 Lbs of concrete in the ground has no problem controlling 500 lbs of pole and fixtures.