Electric and magnetic fields are produced by any wiring or equipment carrying electric current. This includes overhead and underground power lines carrying electricity, wiring in buildings and electrical appliances.
There are ongoing studies around the world looking into the effects of electromagnetic fields on the body.
New Zealand has an inter-agency committee headed by the Group Manager at the National Radiation Laboratory that reports to Government on a six-monthly basis and includes reviews of notable studies in electromagnetic fields being carried out around the world.
In late 2004, MainPower engaged the National Radiation Laboratory to carry out electric and magnetic field recordings at an existing 33kV to 11kV substation and in the vicinity of an existing 66kV overhead power line.
For more information, see the following documents: