One reason you are not allowed to run wires across the bot tom of floor joists is to eliminate the temp tation to use the 12 2 wire for your kitchen gfi as a place to hang laundry.
Run a drop through attic.
Familiarize yourself with the footing situation.
When running pipes from a slab to an attic use an inside wall.
Run the wire or cable to its destination.
Current carrying wires are meant to support only their own weight.
My cable tv is distributed through the attic so it seemed like a good solution to run my home network through there as well.
Climb through the attic access using a ladder if necessary and look into the attic space.
Protect the wall with a thin piece of cardboard etc.
Must be run through bored holes or be attached to a running board.
And while loosely guiding the bit with one hand apply even pressure with the other holding the drill while running it.
With a flashlight examine the attic and locate the path that you will use to run the wire between the two locations.
This may involve fishing it through another wall cavity or out a small hole drilled in the floor.
Methods of proper attic electrical wiring raul no this is not a standard practice and is most likely the result of improper installation of electrical attic wiring.
If you re working from the attic you can drop a weighted string down wall cavity then attach the wire to the string and pull it through.
If no boards or beams run horizontally between the wall studs the pipes can often be fed through the walls up to the attic.
If drilling up through the ceiling expect to pass through a thin coat of plaster and 5 8 of sheet rock and 1 2 inch 1 3 cm of strapping to which the sheet rock is secured.