| MadSci Network: Engineering |
As far as I know, the "EMF controversy" does not involve voltage and electric fields, it only involves amperage and the AC magnetic fields associated with amperage. To calculate the magnetic field surrounding the cable you need to know the amperage, and unfortunately the amperage of utility lines varies depending on time of day (depending on how many electric stoves, heaters, etc., are being used.)
It's probably easier to *measure* the magnetic field in your bedroom that from the power line than to try to calculate it. Professional gaussmeters might be expensive and hard to find, but the Alternative Health community does a thriving business in selling "EMF Meters". I've never bought nor used one of these, so I can't recommend any particular one. Also, since the topic is controversial and outside of normal science, it attracts hucksters and con-artists, therefore there's no guarantee that the meter you buy will be trustworthy or give any kind of meaningful reading. Perhaps you can ask for recommendations in one of the alternative health forums or on EMF-L discussion group:
misc.health.alternativeSince the topic is controversial and political, there are enormous forces standing in the way of anyone admitting that there is a hazard, or anyone making changes to power lines. (Power companies rightly fear that once they move one single power-line for EMF safety reasons, that they will be targeted by millions of lawsuits, and huge crowds of angry parents carrying torches and pitchforks!)
The topic is very controversial in science. A few years ago it was thoroughly "debunked"... yet today there are professional research articles appearing which imply that there certainly *are* biochemical effects from AC magnetic fields. This doesn't prove that magnetic fields cause cancer, but it shows that earlier debunking attempts were probably motivated by politics and not science. See the links to Science News articles here:
Some bio/magnetism articlesAs a parent I have to make safety decisions constantly. How dangerous are magnetic fields? Unknown, but we must keep some perspective and ask how dangerous they are COMPARED TO OTHER COMMON DANGERS. Compared to riding in a car, most everyday dangers pale to insignificance. Compared to standing up in a bathtub, or climbing a ladder, or swimming in a pond, most dangers from environmental "toxin" effects are ridiculously small. On the other hand, magnetic fields might affect the fast-growning cells of our young ones far more than they effect we old decaying adults. Since unfortunately the bio-effects of magnetic fields is such a taboo topic in science, the exact level of danger is still unknown. In the worst case you'll have to decide whether or not to move to a different location which lacks the problem. Or, at least to possibly move the bedroom to the side of the house which is farthest from the power lines.
PS The magnetic formulas for "in a vacuum" work fine for air, wood, concrete, etc. It's only when iron is nearby that the math becomes far more complicated.
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