Power lines
Power lines produce electric and magnetic fields, just like any other wiring or electrical equipment. These are known as extremely low frequency fields.
Strength of electric and magnetic fields around power lines
The strength of the fields around a power line depends on many things. For example, the amount of current being carried.
Extremely low frequency fields get weaker with distance. If you stood 50 to 100 metres away from a power line, the fields would be a similar strength to those inside many homes and offices.
Even if you were standing right under a power line, the fields are well below the public safety limits recommended in New Zealand and overseas. Similar fields can be found close to some electrical appliances.
Health effects of electric and magnetic fields
A lot of research has been done over the past 40 years into whether the extremely low frequency fields generated by power lines and other electrical equipment can be harmful.
The research has been reviewed several times by various national and international groups. Public safety limits are based on the findings of these reviews.
Some studies suggest that there may be a link between:
- living near power lines, or in houses with strong magnetic fields produced by other sources
- a small increase in the number of children with leukaemia.
But the link may be explained by other factors. Laboratory studies do not suggest a connection. So it is not clear whether magnetic fields pose a risk or not.
If power lines do increase the risk of leukaemia, the World Health Organization says there would only be a small impact on public health and safety limits need not be lowered. Reducing exposures from new electrical infrastructure could, however, be considered.
Electric and magnetic fields and your health
Information on electric and magnetic fields associated with transmission lines, distribution lines and electrical equipment.