All motorized equipment found in homes will generate magnetic fields when in operation. Some epidemiological studies have linked exposure to these magnetic fields with increased incidence of cancer, Alzheimer’s disease, and miscarriage. Magnetic fields from properly wired appliances drop off very quickly in an exponential relationship to your distance from them. These fields can be easily measured with a small handheld instrument called a gauss — meter, which allows the user to determine the safe distance from an appliance.
The US government has not yet set reasonable standards for safe exposure levels, nor has it taken a strong position regarding the health effects of magnetic fields. However, various government documents and public utility disclosures state that ifyou are concerned, you can practice ‘prudent avoidance” of these fields. Recommended safe exposure limits set by various experts have ranged from 0.5 milligauss to 1,000 milligauss. Hie Swedish National Energy Administration has recommended that children should not be subjected to magnetic field levels greater than 3 milligauss. The
Bau-Biologie Institute in Germany considers readings above 0.2 milligauss to be a deviation from naturally occurring conditions.
In Division 16 we include information and recommended specifications for designing and building a home in which magnetic fields transmitted by household wiring do not surpass 0.5 milligauss. You can follow the simple guidelines below to limit your exposure to magnetic fields from appliances:
• Design your home so that major appliances are located at a safe distance from sitting and sleeping areas. In doing so, remember that magnetic fields travel with ease through walls made of common building materials, and that areas located out of sight behind an appliance are also exposed. For example, placing a refrigerator back — to-back with a bed, even though separated by a wall, will continually expose a person in that bed to an elevated magnetic field.
• Duration and strength of exposure are both factors. A low-level exposure for long periods of time maybe more harmful than a brief, high-level exposure. For this reason, pay particular attention to fields that maybe generated around sleeping areas.
• We suggest that you buy and learn to use a gaussmeter. With this device, you can measure the fields emanating from appliances. For more information on choosing and operating a gaussmeter, see Division 16.
• Check your home and appliances regularly with the gaussmeter to determine whether field levels have increased. Elevated fields can sometimes indicate that an appliance has developed dangerous ground faults or is about to fail. Early detection of these fields will also decrease the risk of fire or electrocution.
Appliances and Electric Fields
Whereas magnetic fields exist only when appliances are being used, electric fields are present as long as the appliance is plugged in. Unfortunately, few appliances are manufactured in a manner that results in low electric fields. It is possible to rewire appliances so that they operate with reduced electric fields, but this requires the services of an electrician familiar with electric field shielding. Electric fields from appliances are relatively easy to control by following these suggestions:
• Keep appliances unplugged when they are not in use, especially in the bedroom. Not only will this eliminate the electric field but it will also reduce the risk of fire. Although this practice is much more common in Europe, the American Association of Home Appliances and Underwriters Laboratories has also issued a warning stating that small appliances should be unplugged as a fire prevention measure.
• Avoid using extension cords around beds or areas where your family spends a lot of time. They tend to emit high electric fields when they are plugged in.
• Use a battery-operated or wind-up clock next to the bed.
• Wire your bedroom so that the circuitry can be conveniently shut off when you go to sleep, thus eliminating the electric fields. Refer to Division 16 for details.
