Electricity has become an almost indispensable part of most people's everyday life, and there will probably always be magnetic fields of a certain strength in our homes - even if there are no power lines nearby.
Magnetic fields in homes
According to the World Health Organization (WHO) (EHC, 2007), there is no appreciable difference between the average strengths of magnetic fields found in European homes. The fields may be created by power lines outside the home, the house's own installations and various appliances.
Average magnetic fields strengths in European homes lie in the range of 0.025 and 0.07 µT (microtesla). In the USA, magnetic field strengths average between 0.055 and 0.11 µT. The prime cause of this difference is probably that American house installations have a voltage of 110 V, while European house installations have a voltage of 230 V. When the voltage is only half as high, twice as much electric current will - all other things being equal - flow through the system, causing field strengths to double as well. These figures are an average for homes with and without power lines near them.
Fields around electricity supply installations and appliances
Directly under a power line fields may be as strong as around 10 µT. Directly above an underground cable fields may be up to about 30 µT. Immediately close to household appliances fields may be as strong as 100 µT or more. On the other side of the fence surrounding and outside the building housing a substation fields are normally quite weak. Field strengths drop off rapidly with distance. Electrical field strengths depend on the appliance's or installation's construction.