Low-frequency fields in the home
Large power lines are a visible part of our environment. Power lines generate low-frequency electromagnetic fields around them. The field strength attenuates when going further away from the power lines. The structures of buildings attenuate electric fields, but not significantly magnetic fields.
On the other hand, also electric devices and wires within a building generate electric and magnetic fields. If a 110 kilovolt high voltage cable is 50 metres or further away from a building, it is not possible to distinguish between the magnetic field generated by the electrical appliances in the building and by the power lines.
Generally, it can be said that in Finnish homes and work places, the 50 Hz electric and magnetic fields present are well below recommended values. On the basis of measurements carried out in Finland, the average level of fields in the home is slightly below 0.1 µT, and in work places, slightly over 0.1 µT. The magnetic fields caused by indoor transformer substations are an exception, but relative to the number of homes, it is rare for a home to be adjacent to one.
