Questions and Answers About EMF Electric and Magnetic Fields Associated with the Use of Electrical Power.
January 1995.

Electric Power Background

Q. What is power-frequency EMF and how does it compare to other types of fields?

A. The electromagnetic spectrum (right) covers an enormous range of frequencies. These frequencies are expressed in cycles per second (i.e., Hz). Electric power (60 Hz in North America, 50 Hz in most other places) is in the extremely-low-frequency range, which includes frequencies below 3000 Hz.

The higher the frequency, the shorter the distance between one wave and the next, and the greater the amount of energy in the field. Microwave frequency fields, with wavelengths of several inches, have enough energy to cause heating in conducting material. Still higher frequencies like X-rays cause ionization—the breaking of molecular bonds, which damages genetic material. In comparison, power frequency fields have wavelengths of more than 3100 miles (5000 km) and consequently have very low energy levels that do not cause heating or ionization. However, AC fields do create weak electric currents in conducting objects, including people and animals.