There are several key factors to consider in determining the possible presence, depth and protection of underground power lines.Fortunately, free hotlines are available in all 50 states to connect you to professional utility location services that will find you any underground wires for free.The requirements for underground power lines may vary geographically.Although the National Electrical Code specifies the minimum specifications for the underground low voltage circuit, the physical properties of the installation will determine the actual depth.There are two common ways to install underground power lines.The direct burial method is moreConductor cable with sheath, used to resist corrosion elements related to soil and moisture.The minimum depth requirement for direct buried cables is 24 inch, unless installed under a concrete slab with a minimum thickness of 2 inch.In this case, the cable can only be installed at 18 inch deep.Another option is to install an underground track, also known as a pipe that holds independent conductors.When not installedThe metal underground runway, with a minimum burial depth of 18 inch, unless installed under a concrete slab with a minimum thickness of 2 inch, in which case the pipe can only be installed at a depth of 12 inch.When the underground metal runway is installed, the minimum burial depth is only 6 inch.Don't risk your safety if you're thinking of digging any depth.Even small jobs like planting shrubs or trees on your property require you to call 811 before you start digging.Failure to do so may result in damage to the underground system, fines, repair costs and serious injury or death.