Okay, here’s one for the electrical engineers. I have a permanently installed hydraulic lift where the cylinders are going to be replaced with motors & jacks. The 3” line that’s buried in concrete that feeds the current cylinders would be great to running the power to the new motors.

Is that legal? I don’t have a spec for the hydraulic fluid, so I don’t know how flammable or conductive it might be, but we could look at someone cleaning the pipe out.

Any idea where I should look in the NEC for this sort of information?