<Li> Reduced range of electromagnetic fields (EMF) emission, into the surrounding area . However, depending on the depth of the underground cable; greater EMF may be experienced on the surface . The electric current in the cable conductor produces a magnetic field, but the closer grouping of underground power cables reduces the resultant external magnetic field and further magnetic shielding may be provided . See Electromagnetic radiation and health . </Li> <Li> Underground cables need a narrower surrounding strip of about 1--10 meters to install (up to 30 m for 400 kV cables during construction), whereas an overhead line requires a surrounding strip of about 20--200 meters wide to be kept permanently clear for safety, maintenance and repair . </Li> <Li> Underground cables pose no hazard to low flying aircraft or to wildlife . </Li> <Li> Underground cables have much less danger of conductor theft, illegal connections, sabotage, and damage from armed conflict . </Li>

Advantages and disadvantages of overhead transmission cables and underground