Installation Instructions for Direct Burial Poles 6660, 6661, 6662, 6663, 6667, 6610, 6611 Prior to pole installation. check with local authorities for location of utility lines (gas, elev, water) in area where hole is to be dug. Make sure all under ground-wiring has been installed according to local building codes. Post installation N~ DIRECT BURIAL POST A) Dig a hole 16" in diameter and check local building codes for hole depth. B) Layer bottom of hole with 4" of gravel or crushed stone.