Electric & 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.

Although they are often referred to together as EMF, electric fields and magnetic fields are actually two distinct components of electricity.

Electric Fields

Most of the interest regarding possible health effects is related to magnetic fields and not electric fields; however people may notice the presence of electric fields when they are near power lines.

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

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.

See also

For more info

BC Hydro Corporate Safety & Health
6911 Southpoint Drive,
Burnaby, B.C. V3N 4X8

Or call our toll-free number:
1 800 BCHYDRO
(1 800 224 9376)

Last Modified: Aug 30, 2011