[Ray Spencer]

What signs/markings are required for a buried 4+ feet deep 15kV line: at roads or public areas; every "X" number of feet; at junction boxes: what is required (in the State of Iowa)? Mostly on private property, but does cross public roads and one utility owned transmission line. Thank you.

[tkrussell]

National Electric Code only requires that a service lateral, from utility to service, have a warning tape 12 inches below grade.

You need to check with the local municipality for the road and the utility for the transmission line for their requirements.