barry@hprmokg.HP.COM (Barry Fowler) (07/29/89)
But what about the electrical wires surrounding every building, commercial and residential, that we live in??? Our houses, for example have "Romex" (or equiv.) wire wrapped around nearly every room in them. If this premise were true, nearly everyone with electricity would be surrounded by "electrical wires producing electromagnetic fields", given that current is being conducted through the wires. 'Time to rip all of those "bad wires" out of every house and shut off the electricity?? :-)
schiller@adobe.com (Steve Schiller) (08/04/89)
In article <10040012@hprmokg.HP.COM> barry@hprmokg.HP.COM (Barry Fowler) writes: >But what about the electrical wires surrounding every building, commercial >and residential, that we live in??? > >Our houses, for example have "Romex" (or equiv.) wire wrapped around >nearly every room in them. If this premise were true, nearly everyone >with electricity would be surrounded by "electrical wires producing >electromagnetic fields", given that current is being conducted through >the wires. > The early epidemiological studies (around 1979 by Nancy Weirtheimer (sp?) in Denver Colorado) on the effects of 60Hz power wiring in and around residences showed that magnetic fields (not eletric fields) were the culprit in increased cancer rates (luekemia actually) in small children. A couple factors combined to produce dangerous environments in the residences where this occured: 1) the residences were near lines that were carrying the entire (rather large) current of a near by step down tranformer secondary before being distributed to a number of different feeder lines, 2) Some of these residences had improperly wired appliances so that the return current from the appliance went though the earth ground instead of returning along a wire near the power wire that would have canceled some of the magnetic field, and 3) the children who did who did get luekemia lived in the same residence for their entire childhood. The upshot of all of this is that the effects are small and only occur when a variety of factors conspire to concetrate them. But the amazing thing is that there is any biological response to fields of this strenght at all. (I think the fields were around 10 to 20 milligauss - but I can't be sure I am remembering correctly.) Prior to this research (and even after due the obstinace of various people) the safe levels for exposure to electromagnetic radiation were set according to how much heat your body could disapate. In other words, anything below cooking power was fine. Since 1980 a variety of research has been done to show that nerve cells do respond low level magnetic fields either at low frequncies (peak response is around 16 Hz but effects are measured up to 60 Hz) or at high frequencies modulated by a low frequency signal. Steve Schiller