The existence of electric and magnetic fields (EMFs) has been recognised since electricity was discovered, and their characteristics have been the subject of thousands of scientific studies around the world. Research conducted over the past 25 years has increased our knowledge of EMFs. At TransGrid we rely on expert advice on this matter from health authorities in Australia and from around the world.
We monitor information on EMF and we are a member of the national EMF Committee of the Energy Networks Association (ENA). Through this membership, we subscribe to an EMF update service.
The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) is the Federal Government agency responsible for providing health assessments and recommendations to the Government on matters relating to EMF.
Electric Fields are produced every time voltage runs through a wire. The higher the voltage the stronger the electric field. Electric fields are strongest closest to the wires and their level reduces the further away you get. Most materials act as a shield or barrier to electric fields. The level of electric fields is measured in thousands of volts per metre (KV/m).
Magnetic fields are produced by the flow of an electric current through a wire. The higher the current the greater the magnetic field. The strength of magnetic fields is measured in millGauss (mG).
Like electric fields, magnetic fields are highest closest to the wire and their level reduces quickly with distance. Most materials will not act as a shield or barrier to magnetic fields.
EMF Exposure Guidelines and Limitation
The Australian National Health and Medical Research Council's (NHMRC) interim guidelines recommend a limit for the general public of 1,000 mG for full-time exposure to magnetic fields or 10,000 mG for occasional exposure. The NHMRC electric field limit for the general public is 5kV/m for full-time exposure and 10kV/m for occasional exposure.
Typical EMF Fields
The table below provides a guide to the relative strengths of magnetic fields in a range of electrical equipment:
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