Example: could I take 4 pyramid deck blocks and cover with 2x12 pressure treated on edge, pour gravel in that and cover with 2x12, this then would be a solid platform for mounting the outlet. Alternately 6x6's tied together. Harder to work with 6x6 as stores can't cut.
This is because I can't dig down in this area due to soil compaction and multiple utility lines underneath.
314.23 Supports. (B) Structural Mounting. An enclosure supported from a structural member of a building or from grade shall be rigidly supported either directly or by using a metal, polymeric, or wood brace.
(2) Braces. Metal braces shall be protected against corrosion and formed from metal that is not less than 0.51 mm (0.020 in.) thick uncoated. Wood braces shall have a cross section not less than nominal 25 mm × 50 mm (1 in. × 2 in.). Wood braces in wet locations shall be treated for the conditions. Polymeric braces shall be identified as being suitable for the use.