[Bill Schwab]

Pretty standard code for wire of any type to be 18" deep, and cased. 10-3 is way too small a wire to run 40' as well. We usually run 1 1/4" schedule 40 conduit, glued together, then pipe taped. We run a 1/4" nylon rope through the conduit. Then we run 6 gauge cable, one white, one red, one black. The ground is green and we can use 10 gauge by code. Typically, we need a 60 amp double bar breaker on the load center, and, there must be a waterproof quick disconnect (glorified switch) within 10 feet of the spa.

If you don't do it this way, you don't pass inspection. Inspection process typically is, at the point the conduit is buried, at the point the lines are pulled, but before they are hooked up, and, at the point of hook up.

Could you get juiced if you hit the lines? Sure. What would be more likely to happen is you would explode a piece of your shovel, and it would trip the breaker, especially, if it is a GCFI interface. From the sounds of this job, these folks need to learn the dangers of what could happen in a worst case scenario. Like, thier dog thought it was a bone, bit down, then the kid sees the dog having trouble and runs over to help. As soon as the kid touches the dog, you got two formerly living things now playing as smoked meat.