frost line in pa is 42 inches
Below the frost line of your area. Your local building code will tell you what the requirements are.
In western Pennsylvania the frost line falls at 36", when installing underground waterlines 42" is perfered.
I saw a good chart of average frost penetration for Illinois. 10" to 20" for southern Illinois 15" to 30" for central Illinois (frost line for Peoria) 20" to 35" for northern Illinois
It's not a matter of how deep electrical wire should be buried. The wire should be protected by plastic or metal conduit and marked suitably above ground - buried utility. I am certain that you will be burying a water line to the fountain "below the frost line" for your area, so consider placing you electrical wires at the same depth.
Footings, the concrete pads upon which foundation walls are built, must be located beneath the frost line in order to prevent a building from heaving when the ground freezes. If the site is sloped maintaining a constant elevation for the footings would either cause the footings to be above the frost line or significantly deeper than the frost line at one end of the building. Stepping the footings enables them to follow the slope of the site and remain below the frost line without going too deep under the ground. It allows the foundation wall heights to be minimized because the footings are kept as close to the surface as possible.
They are located below the frost line
6" below grade
no Frost
Should be low enough to maintain proper pitch and below the frost line if applicable
Average is 4ft, building code requires water pipes to be at least 6ft deep to be well below frost line and safe from frezzing.
no Frost
Below the frost line of your area. Your local building code will tell you what the requirements are.
According to the building permit section of the Clermont County, Ohio web site "The frost line is 30 inches below grade." See attached link
i dont know whho cares Most concrete foundations are buried 4' to get below the frost line which is around 3'.
24in
42 inches
one metre