What are Electric and Magnetic Fields?
Electric and magnetic fields (EMF) are present everywhere that electricity flows. Electrical appliances, household wiring and electrical power lines all produce electric and magnetic fields.
A Comparison of Electric & Magnetic Fields
Although they are often referred to together as EMF, electric fields and magnetic fields are actually two distinct components of electricity.
Electric fields are produced by voltage in a wire. For example, an electric field is present when an electric appliance is plugged into an outlet, even if it is not turned on. Electric fields can be blocked or shielded by objects such as buildings or trees.
Magnetic fields are produced when electric current is flowing, so they are only present when an electric appliance is turned on. As the flow of electricity - the current - increases, the magnetic fields increase. Magnetic fields pass through most objects and cannot be blocked as easily as electric fields.
Most of the interest regarding possible health effects is related to magnetic fields and not electric fields. So usually, when the term EMF level is used, it is the magnetic field strength that is being referred to or measured.
Public Interest
We recognize that there is public concern about EMF and possible health effects and we are committed to addressing these concerns in an open and balanced matter. This section of our website explains some of the science and research about electric and magnetic fields, outlines BCTC's commitments to addressing public concern and provides a list of other resources.