Magnetic Fields Produced by Underground Residential Distribution System

Increasingly dense residential housing developments have spurred new concerns about electromagnetic fields. The magnetic fields generated by the underground distribution system in such a residential subdivision are assessed in this study. In particular, the magnetic flux densities above the underground cables, around the padmount transformers and junction boxes, and at the service entrance panels are measured. The largest magnetic fields of 95 mG and 148 mG are recorded on the surfaces of the transformer enclosures and junction boxes, respectively, at around 30% to 40% of full load. The magnetic fields reduce to less than 3 mG at a distance of ~1 m from the distribution system infrastructure. Software is developed to estimate the peak magnetic field generated at full load conditions by the underground cables composed of twisted conductors.