Do you wonder if living next to a high-voltage line or the use of an electrical device brings you in contact with a strong electromagnetic field and implies a risk as a result thereof? This section discusses the sources and the field values that we can encounter in daily life.
Live wiring and appliances are surrounded by an electrical field. The strength of an electric field depends on the voltage in a wire. The strongest electric fields are found under overhead transmission lines: just beneath the wires, this field can reach a few kilovolts per metre. Only under a 380 kV transmission line can the limit of 5 kV/m be exceeded. Electrical appliances and machinery and lawnmowers can never cause an electrical field above the threshold value.
The electrical field decreases sharply with distance and is also resisted by barriers such as walls. As a result, the electrical field in homes is minimal, even in homes right next to a high voltage line.
The strength of a magnetic field depends on the electric current in a wire. The strongest magnetic fields occur in magnetic resonance imaging machines (MRI), used for medical imaging (a few teslas).
Fairly strong fields occur nearby motors and other electrical devices (between a few microteslas and several hundred microteslas). The electricity grid generates relatively weak magnetic fields (at most in the tens of microteslas).
The magnetic field also significantly decreases with distance, but is only slightly weakened by walls. There are magnetic fields around us originating from a whole range of sources both outside and inside.
You can find more information about the sources of the magnetic field in daily life in the PDF document “Electricity and health”.