RESUMEN
RESICALC is a computer program that models magnetic fields due to currents on arbitrary arrays and configurations of electric transmission lines, primary and secondary distribution lines, and ground and neutral return pathways. The program conducts network analyses of ground/neutral currents in neighborhoods based on residential loads and impedances in the current path. Experiments were conducted at the Magnetic Field Research Facility (MFRF) in Lenox, Massachusetts to validate the program's field computation. MFRF has a simulated residential electric distribution system that permits the testing of scenarios with a broad range of electrical characteristics. The results demonstrate that the program accurately models fields from complex combinations of supply and ground/neutral currents, and shows how estimated fields may be sensitive to impedance values assigned to the ground and neutral currents. The program has usefulness as an exposure assessment tool when access to residences is not possible, and as a means to estimate fields when planning electrical facility or residential development. Careful mapping of power line and residential coordinates in the program, as well as acquiring the highest quality load and grounding data available, are critical for modeling valid exposure estimates.