healthy house institute

4 Free HHI Books:

Creating a Healthy Household, The Healthy House Answer Book, Healthy Home Building, The Healthy House 4th Edition
Your email will only be used as described in our Privacy Policy

Follow us on Twitter



Proud Supporter of:




Electrical Systems - Chapter 23

By HHI Staff

Prior to designing and building a new house, there are a few things you should discuss with your electric utility. For example, many healthy houses are all-electric, so you should check to see if you will qualify for a lower electric rate. You should also ask if they have an energy-rating program that would allow you to qualify for an energy-efficient mortgage if you incorporate energy-saving features such as tight construction. (RESNET is a clearinghouse for information on energy-efficient mortgages.) And, you should see if your utility offers any incentives. Many utilities offer special deals, or rebates, on energy-efficient lighting, electric water heaters—even heating systems. (This article is from the archives of the original Healthy House Institute, and the information was believed accurate at the time of writing. From "The Healthy House: How to Buy One, How to Build One, How to Cure a Sick One" © 2000 by The Healthy House Institute).


article continues below ↓

We do not strictly control Google ad content. If you believe any Google ad is inappropriate, please email us directly here.

If an electric-power pole must be located near your house, request one that is pressure treated with CCA (copper-chromium-arsenic) salts rather than creosote. It will be the lesser of the two evils. Better yet, ask about underground electric service to keep any type of treated pole far from the house.


The electrical systems in houses today are considerably more complicated that those in houses just 50 years ago. Today we require wiring for televisions, satellite hookups, stereos, security systems, telephones, and computers—not to mention the 120-volt and 240-volt lines for lighting, appliances, and heating. There are three basic health problems to be concerned about: First and foremost, is the danger of electrical shock and possible electrocution; second, the outgassing from plastic electrical components; and third, health effects related to electromagnetic radiation.


Electrical systems also affect the tightness of a house (and the infiltration rate) because electricians drill holes in various studs, joists, and rafters. Plus, there are gaps around electrical boxes through which air currents can move. These small gaps and holes create pathways between the indoors, hidden building cavities, and the outdoors. There have been a variety of airtight construction techniques developed to minimize infiltration around electrical boxes. For example, Thomas & Betts (Nu-Tek brand) and Ryeco Products (R & S Enviro brand) offer gasketed electrical boxes that seal against drywall or plastic sheeting.


There is a Lessco plastic box (Low Energy Systems Supply Co.) that can be used to make a conventional plastic or metal electrical box airtight. If the airtight electrical boxes mentioned above aren’t sealed properly, or if they develop a leak after installation (perhaps from a loose gasket) they can’t be easily resealed unless you tear out some of the drywall. However, if a Lessco box develops a leak, it can be made airtight by drilling a small hole next to the electrical box, then injecting urethane foam into the space between the Lessco box and the electrical box. A variety of these types of energy-related products can be mail-ordered from EFI and Shelter Supply.


For existing houses, you can reduce infiltration by installing thin foam gaskets (available at local hardware and building-supply stores) behind switch and receptacle cover plates. Ryeco Products (R & S Enviro brand) has an Enviroseal insert that can be installed inside existing electrical boxes to tighten them up. K-Products markets a gasketed Perma-Flex Care Cover that you install instead of a regular receptacle cover. It has small spring-loaded plastic doors over the outlet holes to minimize infiltration and discourage children from inserting metal objects.

Basic Electrical Safety

Building codes cover basic electrical-safety issues quite well. For example, codes deal with how heavy wiring must be to handle certain loads, grounding specifications, special requirements in damp areas such as bathrooms and kitchens, etc. In addition, electrical devices (e.g. switches, receptacles, light fixtures, etc.) must meet certain standards to perform their intended function safely.


From a homeowner’s standpoint, there are a number of things that can be done to minimize the risk of electrical shock. For instance, never allow anything to come in contact with outdoor power lines—television antennae, metal ladders, kite lines, and metal poles touching power lines are a major cause of electrocution. Another significant danger involves combining water and electricity—never use hair dryers, radios, kitchen appliances, TVs, etc. if you are in a wet location, such as on a wet bathroom floor. The danger of electrical shock in wet locations can be minimized by installing Ground Fault Circuit Interrupters (GFCIs) in kitchens, bathrooms, garages, and outdoors. GFCIs are now required in these locations by building codes, but they don’t exist in many older houses.


People are also electrocuted when they attempt to repair electrical appliances while they are still plugged in. The chance of an electrical fire can be minimized by repairing or replacing damaged cords, and not plugging too many appliances into the same circuit.


The hazards of electrocution are very real, but because they are well understood and already regulated by existing codes, there is no need for this book to delve into them further. Instead we will focus on issues that are not being adequately addressed.




Receptacles, switches, cover plates, and circuit breakers are generally made of a hard plastic that is subject to very little outgassing. These materials are often well-tolerated by sensitive people. Some sensitive people prefer ceramic, wood, or brass covers, which are sold in hardware and department stores or bath shops. Cover plates are also available in stainless steel.


Circuit breakers are usually housed in a metal power panel that is painted. While minor outgassing from the paint can cause reactions in a few sensitive people, it is generally not a problem. The power panel can be purchased early in the construction process and allowed to air out before installation.


Some electrical components, such as doorbells, use small transformers to reduce the voltage. These can get warm and can give off odors, so they should be located where the smell won’t migrate into the living space (e.g. in an attic or crawl space).


Today, most of the electrical boxes used for switches and receptacles are made of plastic. Plastic boxes aren’t strong outgassing sources, but more-inert metal boxes are still readily available. In airtight construction, well-sealed electrical boxes are required on exterior walls to minimize infiltration. The companies mentioned above can supply special airtight plastic boxes for this purpose.


Light fixtures can be made from a variety of materials such as plastic, ceramic, glass, metal, wood, etc. Because they get warm from the heat given off by the light bulb, low outgassing materials should be chosen. Plastic fixtures are generally poor choices, and wood is marginal—depending on the finish and species. Recessed light fixtures do not collect dust, but they must be airtight if installed in an insulated ceiling.


Plastic-jacketed electrical wiring (or telephone, or TV-cable wiring) can outgas, but the strength of the odor varies by product and by manufacturer. Wiring is more odorous than plastic electrical boxes and switches, but it’s generally not a significant outgassing source because it’s typically inside building cavities. However, it can be a problem for some sensitive people. There are several ways to minimize outgassing into the living space. Some people recommend that plastic-jacketed wiring be run inside metal conduit. This helps minimize outgassing, but it can be expensive. (It will also reduce the electric-field strength, as discussed below.) When electricians pull wire through conduit, they often use an odorous lubricant that can bother some sensitive people. A tolerated liquid soap can be used instead.


There is a type of electric wire on the market that is sheathed in aluminum and is very easy to use. It consists of a plastic jacketed cable that’s encased inside a continuous flexible aluminum sheath. The aluminum acts as a protective metal conduit, and it prevents outgassing. This product is available in rolls and can be easily bent by hand to snake its way through a house. Called Corra/Clad, it’s manufactured by Coleman Cable Systems, Inc. They also make a Metal Clad Squared product that is also totally sealed, and is a little lower in cost.


When upgrading the wiring in an existing house, there are surface-mounted wiring systems that encase the wire in a decorative metal track, thus minimizing any outgassing from the plastic jacketing. One manufacturer is Wiremold Co. These systems are typically painted, so sensitive people should test them for outgassing.


Plastic-jacketed electric wires can be wrapped with household aluminum foil, before the framing is covered with drywall, to minimize outgassing. Outgassing can also be minimized by using foil-backed drywall or foil-backed plasterboard. However, the easiest—and cheapest—way to reduce outgassing is to purchase plastic-jacketed wiring early in the construction process and let it air out for several weeks prior to installing it.

Electromagnetic Radiation

There is widespread interest in the health effects of electromagnetic fields. In fact, many people are more concerned about electromagnetic fields than about indoor air quality. Both are important health issues and both have been downplayed far too much. Is one more important than the other? Well, it depends on who you ask. Without a doubt, we are exposed to far more contaminated air and electromagnetic pollution than at any other time in human history. Even if the effects aren’t immediately obvious, air and electrical pollution must be affecting us all—virtually all the time.


Discussions of electromagnetics in the popular media are often filled with inaccuracies, incorrect terminology, and sensational statements. To clarify matters, we’ll begin with a simple discussion of what electromagnetic radiation is.


Electromagnetic radiation is energy that moves (propagates) from one point to another in the form of electromagnetic waves. As an example, sunlight (which is a form of electromagnetic radiation), in the form of light waves, moves outward from the sun in all directions. Some of it reaches us on the earth. Radio transmission towers send out radio waves (another form of electromagnetic radiation), that are picked up by antennae. Electromagnetic radiation can also be propagated through wires. Overhead power lines, house wiring, and extension cords all routinely carry electromagnetic radiation in the form of electrical power. All types of electromagnetic radiation have electromagnetic fields surrounding them. When electricity is moving through wires, you can measure the electromagnetic fields surrounding the wires. The fields are stronger near current-carrying wires and weaker further away from those same wires.


Electromagnetic radiation, electromagnetic waves, and electromagnetic fields all have two components—an electrical component and a magnetic component. If you want to measure the electromagnetic field around an electric wire, you will either measure the electrical field or the magnetic field. Electrical fields and magnetic fields have different properties and different health effects. Both are invisible.


Electromagnetic waves exist in many different wavelengths. Some are microscopic in length, some are inches long, others are many miles long. All travel at the same speed in a vacuum—the speed of light, 186,000 miles per second. A particular electromagnetic wave always has a specific frequency associated with it. The frequency is the number of wavelengths that pass by a point in a second. If you know the wavelength, you can easily determine the frequency. For example, if a wavelength is a mile long, and we know it’s traveling at 186,000 miles in a second, then it will have a frequency of 186,000 wavelengths per second. (Frequency is usually measured in Hertz, which means cycles [or wavelengths] per second.) If a wavelength is 1,000 miles long, it will have a frequency of 186 Hertz (Hz). Because each wavelength has its own unique frequency, you can use either frequency or wavelength to describe any particular wave.


An electromagnetic wave can vary in its amplitude (intensity). Think of two ocean waves. If they have the same distance between troughs and crests, they have the same wavelength. But if one wave is taller than the other, it has more amplitude. The more amplitude an electromagnetic wave has, the more power or intensity.

Types of electromagnetic radiation

There are billions of different frequencies of electromagnetic radiation: 1 Hz, 2 Hz, 3 Hz, 4 Hz, 5 Hz, 6 Hz, 7 Hz, 8 Hz, 9 Hz, 10, Hz, 11 Hz, through about 100,000,000,000,000,000,000,000 Hz. The whole range of frequencies is called the electromagnetic spectrum. Different frequencies have different properties—and different health effects. Very short wavelengths (those with very high frequencies) are classified as ionizing radiation. When ionizing radiation strikes a molecule, it can strip away some electrons from that molecule, creating ions. This can happen to molecules in the air, or to molecules in living tissue. Longer wavelengths can’t do this, so they’re often referred to as non-ionizing radiation.


As living creatures, we’ve been exposed to various forms of naturally occurring electromagnetic radiation since the dawn of time. As the human species evolved, we adapted to the visible light, and other forms of electromagnetic radiation that come from the sun, as well as to the low-intensity gamma rays and X-rays that come from outer space. Some of this background radiation is good for us. For example, there is a very weak 10 Hz background radiation that’s responsible for regulating our natural biological rhythms. This was discovered by a scientist named Rutger Wever who placed individuals inside well-shielded rooms to protect them from all forms of electromagnetic radiation—even the naturally occurring variety. After a while, the test subjects became completely desynchronized and their metabolic processes started to cycle out of harmony. When they were exposed to artificially generated 10 Hz electromagnetic radiation, their biological rhythms were restored.


Because of modern technical developments, we are now exposed to a phenomenal amount of man-made electromagnetic radiation. But, the health effects of most of these frequencies are not well understood. The radio and television signals surrounding us today are estimated to be 100-200 million times more intense than the naturally occurring background level. The average citizen today is exposed to dental and medical X-rays, microwave ovens and radar, and high indoor radon levels that our forebears did not have to contend with. The biggest controversy has to do with the electromagnetic fields surrounding electrical wires and power lives.


Let’s take a closer look at some of the different forms of electromagnetic radiation—from the shortest to the longest.


Gamma rays

Gamma rays are extremely short, so they have very high frequencies. They are released when materials go through a nuclear decay process. This occurs to a large extent in nuclear reactors and bombs, and to a lesser extent when radon decays indoors. Nuclear power plants are constructed to contain most of the gamma rays within the reactor, but minor releases do occur. Major releases can result from accidents like Chernobyl. Gamma rays are ionizing forms of radiation and, as a result, they can cause tissue damage and cancer, so exposure to them should minimized. 




X-rays are somewhat longer than gamma rays, and they are also ionizing, so they can strip electrons off molecules—whether the molecules are living or not. All X-rays should be considered dangerous, so exposures should be minimized. However, contracting breast cancer may be even more dangerous to an individual’s health. In other words, having periodic mammograms may be less risky than not having them, because you may discover a tumor before it becomes advanced. Fortunately, frivolous X-rays are becoming a thing of the past. At one time, shoe stores used X-ray machines to see how well your feet fit in new shoes. Television sets now emit fewer X-rays than previously.


How much exposure constitutes an acceptable risk? That’s a question open to debate. An occasional dental X-ray is probably less dangerous than a ride in an automobile. That doesn’t mean that some X-rays are without risk—it simply means that, in some cases, they constitute a reasonable risk.

Ultraviolet light

Ultraviolet light has both positive and negative effects. The shorter wavelengths of ultraviolet-light are invisible to the naked eye and, because they are ionizing, we should minimize our exposure to them. Most of the ionizing ultraviolet light to which we are exposed comes from the sun, and the atmosphere tends to prevent a great deal of it from reaching the earth’s surface. You will be exposed to more of it at a high elevation, such as Denver, where the atmosphere is thinner, than at sea level. As the ozone layer in the upper atmosphere gets depleted, more ionizing ultraviolet radiation reaches all of us at all elevations. For people who spend a great deal of time outdoors, this can mean a higher rate of skin cancer. This form of electromagnetic radiation can be created artificially for germicidal purposes to purify air or water.


Longer wavelengths of ultraviolet light are not ionizing, nor are any of the other forms of electromagnetic radiation that have even longer wavelengths. These longer wavelengths of ultraviolet light from the sun do pass through the atmosphere. While too much exposure can result in sunburn, a certain amount is actually beneficial to our health. That’s because long-wavelength ultraviolet light is responsible for activating a steroid-like compound that is naturally secreted by our skin, and converting it into vitamin D, which is then reabsorbed by the skin. Vitamin D deficiency in growing children leads to rickets. Simply standing in front of a window doesn’t mean your skin is absorbing any long-wavelength ultraviolet light—ordinary window glass blocks its particular wavelengths—so you must go outdoors to get exposure to this form of electromagnetic radiation.


While a certain amount of ultraviolet light may be beneficial to health, it can cause a photochemical reaction to take place with some air pollutants, changing them into different types of pollutants. There is also some concern that too much exposure to ultraviolet light from some types of halogen light bulbs can be harmful.


Visible light

Visible light is the form of electromagnetic radiation we are most familiar with. Pure-white light is composed of a variety of wavelengths. When white light is split with a prism, the various wavelengths can be viewed as a range of colors: red, orange, yellow, green, blue, indigo, and violet. However, not all white light is pure-white. When split apart, the range of colors present in sunlight is somewhat different from that of an incandescent light bulb, which is different from a cool-white fluorescent lamp, which is different from a warm-white fluorescent lamp.


Because we have evolved over millennia under natural sunlight, it’s been suggested that sunlight is healthier than artificial light. In fact, there has been much written about the effects of light on health.7 Some of the writing dates back to the 1960s, and it focused on the health advantages of full-spectrum lighting, which mimics sunlight more than conventional incandescent and fluorescent lamps. The early popular literature suggested that one of the problems with most artificial lighting was its lack of low-frequency (longer wavelength) ultraviolet light. Full-spectrum fluorescent lamps are said to mimic sunlight fairly closely. BioLight Systems sells a variety of full-spectrum bulbs and tubes and also fixtures. In addition, full-spectrum fluorescent and incandescent bulbs are available from Lumiram Electric Corp.


There have been many health claims attributed to full-spectrum lighting, but most of the claims are unsubstantiated. In 1986, the U.S. Food and Drug Administration censured a manufacturer of full-spectrum lights for “gross deceptions” in their advertising. While most health effects attributed to full-spectrum lighting haven’t been proven, some people simply prefer full-spectrum bulbs because of the color rendition, or the mood it imparts. Full-spectrum bulbs certainly aren’t universally desirable—occasionally, sensitive people are bothered by full-spectrum lighting. Many full-spectrum bulbs are fluorescent tubes, so it should be noted that many fluorescent lamp fixtures contain a ballast that can outgas into the living space when it gets warm. Prior to 1978, many of these ballasts contained PCBs. Fluorescent bulbs also contain some mercury vapor so, if they are broken, occupants can be exposed to toxic mercury.


As far as positive effects are concerned, reports from the 1980s suggested that exposure to bright full-spectrum lighting could be beneficial in alleviating symptoms of Seasonal Affective Disorder (SAD). With this condition, people experience symptoms of depression, fatigue, weight gain, etc. during winter months because of less exposure to sunlight. Our bodies produce a hormone called melatonin only in darkness, and SAD patients have too much melatonin. More recent studies have found that SAD patients respond to artificial light as long as it’s bright enough, and that full-spectrum lighting isn’t necessary. In fact, some promising results have been obtained with head-mounted devices such as “light visors” and by having SAD patients take a morning walk in natural sunlight. Bright-light therapy certainly seems to help some people with SAD, but there are drawbacks. Common side effects include headache, eyestrain, and feeling “wired.”


Not all people are affected by SAD. In fact, some of us might be getting too much light. With artificial lighting systems, we have extended daylight (or near-daylight) conditions by 4-7 hours, depending on the season. It’s been hypothesized that this extra light means too little melatonin for some people, something that might lead to tumor production.


Selecting healthy interior lighting is not an easy task. However, for most healthy people, the type of lighting is far less important than the chemical pollution inside an average home. And, no matter what type of lighting you choose, it’s always a good idea to spend a certain amount of time outdoors in natural sunlight for vitamin D production—but not so much that it results in sunburn.


Compact-fluorescent bulbs have been promoted in recent years because they are energy efficient and long lasting. Those with magnetic ballasts contain a small amount of radioactive material that can be released if the fixture is crushed. Electronically ballasted models contain no such material, so they are healthier choices. Different models produce slightly different colors of light. Some are very white, which many people find unattractive, while others give off a more pleasing color.


Many halogen bulbs can be 10-40% more energy efficient than conventional incandescent bulbs, but halogen torchieres, which are often used for indirect uplighting, can be very energy inefficient. The filament inside a halogen bulb gets quite hot, and it can give off ultraviolet light. Do not use high-temperature bulbs such as these near flammable materials (e.g. curtains or draperies).


To withstand the high temperature, halogen-bulb manufacturers generally use either quartz glass or borate-silica glass (Pyrex is one particular brand of borate-silica glass). Ultraviolet light is not blocked by quartz glass, but it is blocked by borate-silica glass. When researchers exposed hairless mice to halogen bulbs that gave off excess ultraviolet light, most of them developed skin tumors—some of which were cancerous. So, if you are interested in halogen bulbs, look for ones made with borate-silica (Pyrex) glass, which blocks the ultraviolet-light portion of the spectrum.


Infrared radiation

Infrared radiation has longer wavelengths than visible light. It cannot be seen—but it can often easily be sensed as heat. The warmth you feel radiating from a wood stove, or the burner of an electric range, is infrared radiation. The warmth you feel standing in the sun is also infrared radiation. While infrared radiation can make us feel toasty when the temperature is low, it’s possible to get too much of a good thing. For example, industrial workers who deal with molten iron or glass are exposed to a great deal of infrared radiation. As a result, cataracts were once common in those occupations. Today, protective eye wear is mandatory if workers are to avoid eye damage.


Microwaves are a form of infrared radiation, and they are routinely used to heat food in microwave ovens. Radar is another form of infrared radiation. For years, researchers believed that the only effect microwaves had on life was warmth or heat. Microwave ovens use this principle to cook a pot roast. Medical diathermy machines once used this principle to therapeutically apply heat to living tissue.


Today, there have been a wide range of negative health effects associated with microwave exposure. Paul Brodeur, in his book The Zapping of America, notes that scientists in the former Soviet Union have accumulated a vast amount of information about the health effects of microwaves. They have found that workers with prolonged exposure report symptoms such as “stabbing pains in the heart, dizziness, irritability, emotional instability, depression, diminished intellectual capacity, partial loss of memory, loss of hair, hypochondria, and loss of appetite.” Brodeur has also found evidence of eye strain, cataracts, white-blood-cell-count irregularities, inability to sire male children, sterility, gastrointestinal inflammation, heart disease, increased incidence of Down’s syndrome, and club foot—all attributed to microwave exposure. Most of these effects can be related to strong military or industrial sources of microwaves or radar, but some highway-patrol police officers in this country have reported cases of testicular cancer which they believe is due to resting radar guns on their laps. Less EMF, Inc. offers meters for measuring microwave leakage from microwave ovens.


Radio waves

Radio waves (this category actually includes both radio and television waves) haven’t been the subject of much research, despite the fact that everyone on the planet is bathed in them continuously. But an article in Psychological Reports discussed an experiment where researchers exposed rats to low-intensity UHF radio waves. Compared to an unexposed control group, they found that rats were more active in the early days of the experiment and less active as the days of exposure increased. The UHF-exposed group was also more emotional.


ELF (extremely low frequency) waves

The last category of electromagnetic radiation is one of the most controversial as far as human health is concerned. ELF (extremely low frequency) waves have extremely long wavelengths, many miles in length. The electricity we use in the U.S. is an alternating current that operates at 60 Hz. In Europe, power is transmitted at 50 Hz. All the wires that carry electricity across the countryside, into, and throughout, American homes are surrounded by 60 Hz ELF electromagnetic fields. High-voltage power-transmission lines are surrounded by much stronger fields than the wires in our houses.


It is these 60 Hz electromagnetic fields that have raised the most public concern, and led to a great deal of scientific research. Various studies have examined their relationship to cancer (especially leukemia) and rates of miscarriage. And laboratory experiments have indicated that ELF fields can affect fetal development in swine, chickens, and rabbits. In his book, Currents of Death, Paul Brodeur documents many of these dangers—as well as the negative health effects associated with video display terminals.


Electrically induced disease

Our bodies operate by sending weak electrical signals through the nervous system. Our nerves act like tiny electric wires, continually transmitting electrical signals throughout every part of our bodies. Dr. Robert Becker has documented many of the fascinating ways our bodies use electricity in his book The Body Electric. He suggests that the man-made electromagnetic radiation we are routinely exposed to could be negatively affecting the weak naturally occurring signals inside our own bodies. According to Becker “the entire population of the world is willy-nilly the subject of a giant experiment.” Becker believes ELF fields may have the greatest effect on health because they fall in the same frequency range as many of the natural signals in our brains. At the same time, Becker notes that there are beneficial uses of electromagnetic fields. For example, some researchers have found that electro-therapy can be used to speed up the healing process. Electro-therapy can also relieve pain, reduce edema, dissolve hematomas, and it has been found useful in curing drug addiction.


Paul Brodeur has written extensively on the subject of electromagnetic fields and health. Three in-depth articles have appeared in The New Yorker and he has written three popular books. Brodeur’s writing contains a great deal of useful information, but some of his conclusions are controversial. One environmentalist calls his Currents of Death a “windy, unreadable diatribe, designed only to scare and make money—all heat and no light.” By implying that the government, military, and the entire electrical industry are involved in a massive cover-up and conspiracy, Brodeur does a tremendous disservice to all the legitimate research that is being done.


There is, in fact, a great deal of legitimate research into the biological effects of electromagnetic radiation, and over 10,000 papers have been published on the subject. Much of the research is done in laboratories to see how electromagnetic radiation affects living cells. For example, scientists have examined how electromagnetic radiation affects a cell’s membrane, how it affects calcium flow from cells to the brain, its affect on how cells communicate with each other, etc. Biological Effects of Power Frequency Electric and Magnetic Fields—Background Paper by the U.S. Congress, Office of Technology Assessment contains a summary of the most significant studies that have been done. Questions and Answers: EMF in the Workplace lists over 20 pages of references for research papers and studies on EMFs. Still, many professionals in the U.S. often dismiss the possibility of negative health effects. Yet in the Soviet Union, the following clinical conditions were accepted as sometimes being the result of “radiofrequency radiation sickness syndrome”: dermographism, tumors, hematological aterations, reproductive and cardiovascular abnormalities, depression, irritability, and memory impairment (among others).


Research into the health effects of electromagnetic fields is costly—running into tens of millions of dollars every year—yet much of the work has yielded inconclusive and contradictory results. Sometimes effects are noted one day, but not the next. One theory suggests that microscopic iron-oxide particles (called magnetite) in the air could affect the results. While the magnetite particles apparently pose no threat to human health, they could contaminate electromagnetic-field studies and invalidate the findings.


Other studies use statistics to see if various diseases are more or less likely when people are exposed to electromagnetic radiation. The vast majority of this epidemiological research deals with the 60 Hz electromagnetic fields found around electric wiring and appliances. The Electric Power Research Institute (EPRI), which is sponsored by electric utilities, funds a considerable amount of this research.


It’s important to remember that an electromagnetic field is composed of both an electric field and a magnetic field. Researchers are in agreement that electric fields do not cause cancer or chromosomal damage. In general, most researchers believe magnetic fields are more dangerous. However, some people feel it’s important to minimize our exposure to both electric and magnetic fields—just to be on the safe side.


While more conclusive research is needed, many people are demanding lower fields and less exposure. Others are suing utilities and manufacturers. It’s been estimated that $1 billion is spent each year on litigation while “only” $20 million is spent annually on research. There will no doubt be more money spent on both research and lawsuits but, because of the complexity of the work, it’s unlikely there will be a definitive answer soon. In fact, according to one writer, “many researchers believe a truly scientific study…can never be done.”


The earth is surrounded by a magnetic field. This is sometimes called a geo-magnetic field, and it’s what causes a compass to point North. This field is not the same thing as the magnetic field surrounding an electrical wire. The earth’s magnetic field is static; like that of an iron magnet, it doesn’t change its direction. The magnetic field around an electric wire is constantly changing, or alternating—60 times a second in North America, 50 times a second in Europe. While most of the research on magnetic fields deals with alternating fields, there is some evidence that there are static geomagnetic hot spots in different locations on the planet where negative health effects are more likely to show up.43 This is a fairly controversial subject—even more so than health effects related to electromagnetic fields in general—but some dowsers (people who can locate underground water supplies) claim they are able to detect such hot spots. Of course, dowsing is another controversial subject.


Electrical sensitivity (ES)

The concept of multiple chemical sensitivity (MCS) was once scoffed at by researchers and medical professionals alike. While MCS still isn’t a universally accepted diagnosis (the American Medical Association has no official opinion on the subject), hundreds of credible doctors and scientists have seen enough cases that they’re convinced it exists—in perhaps millions of people. Similarly, when first reported, electromagnetic sensitivity (ES) was thought to be a psychosomatic condition. But, ES is being recognized more and more. Sweden appears to be an early leader in ES research.


Common ES symptoms vary, but most are skin-related or neurological—headache, nausea, fatigue, dizziness, tingling or prickling sensation on the skin, burning skin or eyes, difficulty concentrating, memory loss, muscle or joint pain, and heart fluctuations. A few people report much more severe reactions like paralysis, seizures, and unconsciousness. There appear to be three groups of people who are more likely to be affected by electromagnetic fields: individuals with MCS, computer users, and those who work around high-strength electromagnetic fields.


Based on anecdotal reports, ES does not seem to be as common as MCS. In fact, it appears that many (but not all) people with ES got MCS first, then, as their bodies became weaker and more worn down, they developed ES. When such people begin regaining their health, the ES symptoms often diminish first, then the MCS symptoms decrease in intensity. It’s been estimated that roughly 21/2% of chemically sensitive people also have ES—but there are also people with ES that don’t have MCS. There could easily be tens of thousands of people in the U.S. with electrical sensitivities.


One individual with ES has slurred speech and her legs buckle whenever she’s around things like video display terminals, negative-ion generators, burglar-alarm systems, and San Francisco’s BART train tunnels. Everyday electrical components, such as televisions and dimmer switches, have been implicated in causing negative health effects in people with ES. In extreme cases, individuals must live in houses containing no electricity whatsoever in order to minimize reactions. For them, even talking on the telephone, with its weak electrical signals, can cause problems. FEB (The Swedish Association for the ElectroSensitive) is an international organization offering information on ES.


Computer users

It’s been widely recognized that computer users can develop carpal-tunnel syndrome and vision problems. Other common complaints involve eye strain, burning eyes, and blurred vision, as well as headaches, and neck problems—symptoms that are often reported by people with ES. The National Association of Working Women found significant numbers of workers reporting nausea, dizziness, or constant exhaustion related to computer work. A 1992 study compared computer-using women in Finnish offices who had miscarriages with those who gave birth. It found that those who worked at computers with higher-strength magnetic fields were 3.4 times more likely to have a miscarriage. Less EMF, Inc. sells screens to reduce electromagnetic emissions from computer monitors.


Ham-radio operators

An editorial in Amateur Radio Today discussed the health effects of the powerful square-wave electromagnetic field generated when sending Morse-code messages. It pointed out that there seem to be more personality problems with Extra Class operators than with those operators who don’t send Morse code. This may be due to the low-frequency fields (about 6 Hz.) generated by the amplifier. The editorial suggests that “it won’t kill you in a day or a week, but slowly, over a period of years, it may be changing your personality (not likely for the better) and shortening your life.” A physician, who is also an amateur radio operator, has recognized that there can be a risk, and he has compiled a list of 16 preventative measures that include keeping equipment at a reasonable distance, using minimal power, etc.


The cancer connection

Do electromagnetic fields cause cancer? The best evidence comes from studies done on people who work around electrical equipment (e.g. radar operators, electricians, linemen, and welders). The Labor Institute has summarized the results of a number of epidemiological studies and found that electrical workers seem to have a higher risk of contracting leukemia or brain cancer than the general population. In examining 8 studies, they found one study where electrical workers were no more likely than the general population to get leukemia. The other 7 studies found more risk in the electrical workers, ranging from 1.23 times more likely up to 3.8 times more likely. In five separate studies, the increased risk of contracting brain cancer in electricians ranged from 1.42 times more likely than the general population, up to 3.9 times more likely.


The most controversial facet of this subject has to do with whether or not electrical power lines cause leukemia. The debate began with a 1979 study, then another in 1982, that reported finding increased cancer rates in people living near certain types of power-line configurations. Over the intervening years, many additional studies have been done. Some have found increased cancer risks associated with power lines, some have not. After weighing all the evidence, in 1996, the National Research Council of the National Academy of Sciences determined there is no clear evidence of a power-line/cancer risk. They stated that, at best, the evidence is “inconsistent and contradictory.”


Prudent avoidance

Do electromagnetic fields cause disease? Some of the evidence indicates conclusively that they do, but other evidence is weak. High frequencies (e.g. gamma rays and X-rays) should be avoided at all costs. But the seriousness of 60 Hz fields is open to interpretation. While, in some cases, they may pose a serious threat, the low levels most healthy people are exposed to in daily life don’t appear to be extremely dangerous. But, we are all bathed in electromagnetic radiation of all kinds, and there are undoubtedly subtle biological effects that can’t easily be measured. Just because there isn’t widespread, scientifically acceptable proof, doesn’t mean we should ignore the issue.


Because of the amount of research funding and press coverage this subject is receiving, the American Physical Society (the largest organization of physicists in the world, with over 43,000 members) has stated that “more serious environmental problems are neglected for lack of funding and public attention.” Without a doubt, there are much more serious health issues to worry about. What needs to be done is to put things in perspective.


Dr. Granger Morgan, Head of the Department of Engineering and Public Policy at Carnegie Mellon University, has written about the subject, and acknowledged that there may be a problem. He suggests adopting a policy of “prudent avoidance.” This means you should avoid prolonged, unnecessary exposures to electromagnetic radiation whenever it’s reasonable to do so—but you don’t need to get carried away. For example, you probably shouldn’t go camping under a high-voltage power line, but don’t go so far as to rip all the wiring out of your house. Fortunately, there are a number of things that can be done to reduce your risk—sometimes substantially. We will probably know much more about this subject as time goes on, but in the meantime, prudent avoidance makes a great deal of sense.


Measuring electromagnetic fields

It’s very difficult to guess at the strength of electromagnetic fields. For example, there can be weak fields where you’d expect high-strength ones, and strong fields in unexpected places. So, to get a good understanding of the electromagnetic environment, the fields must be measured, and electric fields should be measured separately from magnetic fields. The biggest concern is over the 60 Hz fields surrounding electrical appliances and wiring, but microwaves are also often measured. Several companies sell hand-held meters that can be used to measure these fields. Costs range from less than $100 to over $1000. The low-cost meters can be somewhat inaccurate—one expert has found that in some situations they can be off by 100%—but they’re generally suitable for obtaining readings in residences.


Because electric utilities have gotten so many questions on the subject of electromagnetic fields, they often have meters themselves, and they will sometimes measure the fields around your house for you. However, they often won’t measure them indoors, and they almost never feel electromagnetic fields are a health problem. To seriously evaluate the fields in a house, you should hire a person who is familiar with the subject, or purchase a meter and measure the fields yourself.


If you are interested in measuring all forms of electromagnetic radiation (gamma rays, X-rays, ultraviolet light, visible light, infrared radiation [microwaves], radio waves, and ELF waves), you’ll find it very difficult to locate someone with the proper equipment, it will be very expensive, and there will be little guidance as to what constitutes safe levels. The vast majority of today’s concern and research involves the ELF fields surrounding electrical equipment and wiring, so they’re the ones you will probably be most interested in.


Magnetic fields are measured in a unit called a milliGauss (mG.) with an instrument called a Gaussmeter. A milliGauss is 1/1000th of a Gauss. With ELF fields, most people are in agreement that you should avoid long-term exposure to fields above 3 mG. Others believe 3 mG. is too high, that 1 mG or 2 mG. is a better number.59 There isn’t a great deal of solid evidence to support either figure, but the length of exposure is believed to be a very important consideration. For example, 8 hours of exposure to a 5 mG. field is thought to pose greater risk than a few minutes of exposure to a 50 mG. field.


Electric fields are measured in units of volts per meter (v/m). Stronger electric fields are measured in kilovolts per meter (kv/m). A kilovolt is 1,000 volts. Because most people don’t believe electric fields are as dangerous as magnetic fields, there is little consensus as to what constitutes a safe level.


The National Electromagnetic Field Testing Association (NEFTA) maintains a listing of professionals who do electromagnetic field testing. Individuals who have a certificate from the International Institute for Bau-Biologie and Ecology, Inc. may also be able to do this type of testing. Electromagnetic field testing devices are available from Befit Enterprises Ltd., F.W. Bell, Less EMF, Inc., Magnetic Sciences International, N.E.E.D.S., and Tech International Corp.

Minimizing exposure

Minimizing one’s exposure to all forms of electromagnetic radiation can be difficult because we are surrounded by so many frequencies, and different frequencies require different control methods. For example, several feet of concrete or water are necessary to protect one from the gamma rays of a nuclear reactor, while thin lead sheeting works well against X-rays. Visible light can be blocked by a piece of cardboard. In houses, most of the concern involves 60 Hz ELF fields, so that’s what our discussion will center on.


If there’s a strong formaldehyde source in your house, it can contaminate the entire living space. But if there is a strong electromagnetic source in your house, it generally only contaminates the area immediately surrounding it. This is because electromagnetic fields lose their intensity as you move away from the source. This is an important difference between chemical pollution and electrical pollution.


You can reduce your exposure to electromagnetic fields, and your health risk, by either lowering the strength of the fields, or spending less time near the fields. If you have a high-strength field somewhere in your house, and you walk by it occasionally, you probably aren’t at great risk. But if the high-strength field is near your bed, you will be at greater risk because you will be exposed to it all the time you are in bed.


All houses—even those that are specially constructed to reduce electromagnetic-field strength—will have some isolated areas of strong 60-Hz electromagnetic fields. These are sometimes called electromagnetic hot spots. The only way to eliminate them completely would be to live in a house without electricity—something few of us would be willing to do. But there are many things you can do to minimize your risk.


Magnetic fields and wiring

When electricity is flowing through a wire, you can measure both a magnetic field and an electric field around the wire. The strength of the field is highest right next to the wire, and it diminishes further from the wire. In most residential situations, it’s difficult to measure either field one or two feet away from most of the wires in a house. If an appliance is plugged in, but not turned on, there will not be any current flowing in the wire. When no current is flowing, there will be no magnetic field—but there will still be an electric field (unless there is a power failure). So, you don’t have to actually be using any electricity for there to be an electrical field present—but an electrical appliance must be in use for there to be a magnetic field present.


Magnetic fields are very difficult to block, but they can often be reduced in strength. Here’s how. The electricity in our houses requires two wires. (Actually, electrical codes also require a third wire—a ground—but it should never have any current flowing in it.) Each of the two wires has an electric and a magnetic field. If the two wires are very close together, the magnetic fields tend to cancel each other out. The closer together the wires are, the more the field strength is diminished. If the wires are close together, and twisted around each other, the magnetic fields cancel even further—resulting in extremely low magnetic fields.


To actually block magnetic fields requires a special shielding material. While lead will block X-rays, it won’t block magnetic fields; you need a special ferrous alloy containing iron, nickel, or cobalt. The success of shielding depends on the field’s direction, size, and shape with respect to the shield, and the intensity of the field, so shielding materials are only effective in certain situations.60 Magnetic shielding can be quite expensive so it’s generally only used in very specialized applications. Plus, it usually requires a knowledgeable consultant, such as M. Spark Burmaster, or Neuert Electric & Electromagnetic Services. To locate a consultant in your area, the National Electromagnetic Field Testing Association (NEFTA) maintains a listing of professionals who do electromagnetic field testing, and who would be knowledgeable in reducing field strengths. People who have a certificate from the International Institute for Bau-Biologie and Ecology, Inc. may also be able to do electromagnetic field testing.


Years ago, when houses were first being wired for electricity, knob-and-tube wiring was common. This involved attaching individual wires to ceramic insulators (knobs) or, when passing through combustible materials, threading the wires through ceramic tubes. In knob-and-tube wiring, the two wires were separated by a foot or more, so the magnetic fields didn’t cancel each other out. As a result, older houses that still have knob-and-tube wiring also have high-strength magnetic fields. Today, the vast majority of houses are wired with a material called romex. Romex is a plastic-jacked product that has the insulated wires packed very closely together in a single bundle. In most applications, the magnetic fields around romex are so low that twisting isn’t necessary. So, in most new installations today, the wiring itself isn’t a contributor to strong magnetic fields.


Electric fields and wiring

While magnetic fields can’t be easily blocked, electric fields can. In fact, outdoors they are often blocked by trees and buildings. However, because most of the health concerns are related to magnetic fields—not electric fields—many people don’t worry about electric-field reduction. Still, there are some hypersensitive people who are bothered by them.


To effectively block the electric fields associated with the electric wiring in a house, you can run all the wires through metallic conduit that has been properly grounded. This is commonly done in commercial buildings, but it’s unusual in residences because it costs considerably more than using romex. However, it will block electric fields effectively. Romex is generally not used inside metallic conduit—individual insulated wires are used instead. These can be twisted together before they are pulled through the conduit to minimize magnetic field strength. Twisted wires inside grounded metal conduit will give you very low magnetic and electric fields.


Because there will be an electric field present around wiring, even if there is no electricity being used, one way to eliminate the electric field is to turn off the circuit breaker at the power panel when electricity isn’t needed. However, this can be inconvenient, and circuit breakers aren’t really designed to be turned on and off frequently. Another approach is to install a demand switch. This device will automatically disconnect the circuit and cut the flow of electricity when there is no demand for it. Then it will allow the electricity to flow again automatically when power is needed. So, with a demand switch on a particular circuit, there will only be an electric field around the wires in that circuit when something is turned on. Demand switches are available through International Institute for Bau-Biologie and Ecology, Inc. and most professionals who specialize in electromagnetic field reduction.

High-current wires

The more current a wire is carrying, the stronger the magnetic field. For example, a wire running to an electric stove will conduct more current (when the stove is turned on), and have a higher-strength magnetic field, than a receptacle circuit serving a single light bulb. To minimize your exposure to high-current wires in new construction, you can simply route them in locations where you won’t spend a great deal of time. For example, you might route the heavy wire from the meter to the main circuit-breaker panel inside a closet wall rather than behind the wall where your bed’s headboard will be. By looking carefully at a floor plan, you can usually find a way to run high-current wires so they avoid bedrooms and other places where you spend the most time. If you run wires through an attic, rather than under the floor, you will be further from them most of the time. This is especially important in rooms where children are likely to be playing on the floor. In most cases, electricians run wires by the shortest path. Wiring for reduced-field exposure takes a little more wire, but the added expense is usually minimal.


In an existing house, it’s possible to relocate high-current lines if they run near areas where you will receive a lot of exposure. Or, you might rearrange your furniture so you don’t spend as much time near those wires. For example, you might move your bed to a different side of the room, or move the couch to a different wall.


There are a variety of wires in a house that carry very low amounts of current—telephone lines, doorbell wires, wiring for home security systems, television cables, etc. They have tiny electro-magnetic fields, and are generally not considered a health problem.


Entrance wires

The main power line coming into a house carries more current than any of the individual wires in the house. Therefore, it can be surrounded by strong fields. In the past, the overhead wires running from the utility pole to the house were usually separated, thus their fields didn’t cancel each other. Today, entrance wires are often twisted together, so they tend to have much lower fields. Still, because of the amount of current in entrance wires, it’s best to locate them, and the meter, in a place where they won’t have a big impact indoors. For example, a meter can be located on an exterior wall that has a closet on the other side, or it could be mounted on the garage.


Most of the underground entrance wires being used today are twisted together, so they have low-strength fields—plus they are out of sight. Some older buried installations didn’t use twisted wires. Though not common, some had wires buried in separate trenches, so they had high-strength fields. Many electric utilities will run underground wires from a utility pole to a residence, but there is a cost involved—underground wires can cost 2-10 times as much as overhead ones.


If the entrance wires (buried or overhead) are twisted, but still have high-strength fields, it is because something is out of balance. This can occur if the neutral wire’s connection is corroded, or if some current is flowing on plumbing lines (see below). Both situations should be corrected.


Neutral problems

The two current-carrying wires in a wiring system generally have different-colored insulation. The wire with black insulation is called the hot wire. The wire with white insulation is called the neutral wire. (In some cases, a hot wire will have red insulation.) The ground wire either has green insulation or it is bare, without any insulation.


Neutral wires from different circuits should never be connected together. If they are, it’s a violation of the electrical code. While it’s not an uncommon practice, it can lead to high magnetic fields. Here’s how. In a correctly wired house, the current flows from the power panel, along the black wire, to an appliance (or a light bulb, a heater, or some other electrical device), then the current returns on the white wire. Such a circuit is balanced. As we said earlier, in most wiring today, the white and the black wire are very close together, so their magnetic fields cancel each other out—but only if the fields are balanced. If the white wires from two, or more, circuits are connected together somewhere, the current will flow along the black wire to the appliance, then part of the current will return on one white wire and part of it will return on a different white wire. If all the white wires are bundled very close to all the black wires, the fields will cancel each other out. But multiple circuits rarely have their wires all bundled together. The result is one black wire and one white wire next to each other that are unbalanced, and another white wire somewhere else that is also unbalanced. This can mean strong magnetic fields.


Neutrals are most often incorrectly connected together inside a junction box. This can occur when an electrician is working on an existing house and assumes all the wires in a box are on the same circuit—when they are not—and he connects the neutrals together.


Grounding problems

Some of the highest strength magnetic fields in houses are the result of grounding problems. As we said earlier, the ground wire should never be carrying any current. It’s only there as a safety factor. If a ground wire is carrying any current, there can be strong magnetic fields.


In most correctly wired situations, the neutral wire is connected to the ground wire at the service-entrance panel—where the main shut-off switch and the individual circuit breakers are—and nowhere else. If the ground and neutral wires are connected together somewhere else, the current will flow along the black wire to an appliance then part of the current will return on the white wire, and part of it will return on one or more ground wires. The current in the individual wires won’t be balanced, the magnetic fields won’t cancel, and strong magnetic fields can be measured.


Connecting grounds and neutrals together in the wrong place is also in violation of the electrical code—but it does occur. For example, many houses have a main service-entrance panel, as well as one or more subpanels. According to the electrical code, the neutrals and the grounds should only be connected together at the service-entrance panel. They should never be connected together at a subpanel. But they sometimes are. This gives the current multiple return paths on which to travel from the subpanel back to the main panel. This means the fields in the individual wires won’t be balanced, so they won’t cancel each other, and the magnetic fields can be high.


Grounding and water lines

The electrical code requires that metallic plumbing systems be grounded. This is a very important requirement and it should not be ignored. However, sometimes there can be current flowing on water pipes. If this is the case, then the water lines themselves will be surrounded by electromagnetic fields—often strong fields. When current is flowing on the pipes, it isn’t flowing where it’s supposed to (on wires), so the fields aren’t balanced, they don’t cancel, and magnetic-field strength is high.


Sometimes, a grounding problem exists in a neighbor’s house, but it affects the electromagnetic fields in all the houses in the neighborhood. This can occur when houses have metal piping, and the underground piping is also metal. In such cases, all the houses in the neighborhood are electrically interconnected through their plumbing lines.


Strong fields can also be found on metal gas pipes. This is dangerous because energized pipes (water or gas) will slowly deteriorate due to galvanic action. This can eventually lead to a leak and an explosion.
Grounding problems can be corrected, but they must be done carefully, and in full compliance with the electrical code. The techniques are too detailed to go into here, and they are often unfamiliar to many electricians. Theory and remedial techniques are discussed in Tracing EMFs in Building Wiring and Grounding, by Karl Riley.


Metal building components

Sometimes metal components of a building (e.g. steel studs, aluminum siding, metal roofing, etc.) become energized if a black (hot) wire is shorted against them, or they become an accidental neutral path instead of (or in addition to) a white wire. This can lead to strong fields throughout a house. Just as with current flowing on water pipes, this means the current isn’t going where it’s supposed to. This can be the result of several problems, such as a short circuit—or a problem in a neighbor’s house that is being transmitted through metallic water lines to your house. Such a problem should be corrected. Metal components should never be energized.


It’s been suggested that living inside a metal-sided (or metal-roofed) house will shield the occupants from the beneficial natural background radiation that pulses at about 10 Hz, thus affecting a person’s biological rhythms. If every piece of metal siding is well-grounded (a difficult thing to accomplish), it can block some wavelengths—but many of those wavelengths will pass through the windows, so the occupants aren’t completely shielded. Also, occasionally being outdoors will allow a person to be exposed to the natural background radiation on a periodic basis. In reality, metal-sided houses don’t seem to have much of an effect on biological rhythms.


Among sensitive people, there is a small subpopulation that have metal sensitivities. They report various symptoms when around very much metal, but the mechanism involved is not understood. They may be reacting to minute changes in background-radiation levels, or perhaps a slight current flowing on the metal, or perhaps to the metal acting as an antenna. Metal-sensitive individuals are often electrically sensitive, and chemically sensitive as well. For them, extreme care is necessary to design a tolerable house. Fortunately, such sensitivities don’t seem to be common.


Power panels

Within the main service-entrance panel itself, as well as inside subpanels, the black and white wires are run to different places. For example, the black wires are run to circuit breakers (or, in older panels, to fuses) and the white wires are run to a bar called a neutral bus or busbar. Because the wires are separated inside the panel, the magnetic fields don’t cancel each other. As a result, power panels tend to have strong magnetic fields, so they should be located away from places where you spend a lot of time. Keep in mind that the panel is surrounded on all sides by a magnetic field—not just the front. A panel in a basement might seem to be well isolated from the living space, but if it is directly under your bed or easy chair, you could be exposed to its magnetic fields. Or, a panel might face into one room, but only be separated from the adjacent room by a 1/2" layer of drywall.


Power panels are necessary, but the electromagnetic field risk can certainly be minimized. Simply mount the panel in an out-of the way location, or in a location where you don’t linger. In a small house, a central hallway can be a reasonable compromise. You might walk by the panel several times a day, but that’s better than having it near your bed where you would have several hours of continuous exposure.


In an existing house, power panels can be expensive to relocate. So, the easiest way to reduce exposure is to rearrange furniture.


Mu metal

In some instances, particularly in existing houses, it can be very difficult to relocate a power panel, or to relocate furniture to minimize your exposure to EMFs. In such cases a special shielding material known as Mu metal can help. It is designed specifically to block magnetic fields, however it is not perfect. This is because, in most cases, magnetic fields cannot be blocked completely, but they can usually be reduced in strength. The amount of reduction will depend on several factors such as the frequency, source, and strength of the magnetic field, the shape of the area to be shielded, any seams in the Mu metal, the distance from the Mu metal to the source, the orientation of the Mu metal, and the thickness and heat-treatment properties of the Mu metal. So, it can be helpful to speak with someone knowledgeable to discuss your specific situation before purchasing Mu metal—because it can be fairly expensive. Less EMF, Inc. sells Mu metal in both a foil and a thicker plate material.


There are also electrically conductive fabrics available from Less EMF, Inc. that can be used to minimize electric (but not magnetic) fields. When this material wrapped around wires or appliances, and is properly grounded, it will reduce your exposure to electric fields (but not magnetic fields). It is sometimes used under mattresses or sheets in a bedroom.



Common household appliances are often surrounded by high-strength magnetic fields, especially if they contain transformers or motors. This is because, when a single wire carrying electricity is looped (like a coil of rope), each loop multiplies the magnetic field. Electric motors and transformers have many loops of wire in their windings, so they have more-intense magnetic fields than, say, an extension cord. Coils of wire don’t multiply electric fields, so if an electric motor is plugged into an extension cord, the motor and the cord will have similar electric fields.


Many manufacturers are starting to produce products with reduced electromagnetic fields. However, there are still plenty of appliances being made that have high-strength fields. If you are buying any new electrical device—from a power drill to a washing machine—and you ask the salesperson if it has reduced electromagnetic fields, they will probably have no idea. The best thing to do is to actually measure the field in the store. For example, if you are in the market for a new television, you can easily compare several similar models by walking in front of them with a hand-held Gaussmeter.


If you have existing appliances with high-strength fields, you have several choices. If money is no object, you can replace them with low-field appliances. Or, with something like a television, you can simply move your chair further away from it. After all, electromagnetic fields drop off in intensity as you move away from them. Clock radios can have very strong magnetic fields, and they are often located near your head while you’re sleeping, so it isn’t unusual them to be responsible for more exposure than everything else in the house. The solution is simple—just move the clock radio a few feet away from the bed. You might also consider a non-electric wind-up clock, or a battery-operated clock with low-strength fields. With other appliances, you can move away from them after turning them on. For example, don’t stand within 2-3' of an operating microwave oven. This is easier to do if the microwave oven is off to one side of the kitchen—away from the main work area. (Microwave ovens are sources of both microwaves and ELF waves.)


With appliances, distance is very important. Even low-field appliances often have high-strength fields very close to them. Unless you are willing to do without electrical appliances completely, the best way to minimize your risk is to use low-field models, keep your distance from them when they’re operating, and reduce your exposure time. The booklet EMF In Your Environment: Magnetic Field Measurements of Everyday Electrical Devices by the EPA contains a listing of high, average, and low field strengths at different distances for many typical household appliances. Although it doesn’t list manufacturers, it is helpful to have a copy along with a Gaussmeter when shopping for appliances. When you measure the actual magnetic field around an appliance, you can look it up in the booklet and determine if it is high or low for that particular type of appliance. For example, let’s say you measure a magnetic-field strength of 80 mG. 6" away from a washer in an appliance store. According to the booklet, at a 6" distance some washing machines will be as high as 100 mG. or as low as 4 mG. With 80 mG. being on the high side, you might want to look at a different brand. But distance is also important. The booklet also lists readings further away—at 4' no magnetic field was measurable from any washing machine.


Heatway and Bask Technologies LLC (SunTouch) both have radiant electric heating systems designed to use under ceramic-tile floors that, according to the manufacturer, generate a low 4 mG. magnetic field 1" above the floor. The field strength will be even less at a greater distance above the floor. By comparison, there is an radiant electric system made by NuHeat Industries Ltd. with a magnetic field strength that ranges from 25-300 mG. at 1.2" above the floor.


Electrical fixtures

Dimmer switches, doorbell transformers, and magnetic fluorescent-lamp ballasts have strong magnetic fields around them because they contain small coils of wire. Electronic fluorescent-lamp ballasts have lower-strength fields, so they should be used whenever possible. Other devices should not be mounted near beds or locations where furniture will be placed.


Ceiling-fan motors can have high-strength magnetic fields (when operating), but they are often up high, away from where you typically sit in a room. But in a multiple-story house, a fan on a lower level might be directly under a child’s upstairs bed. The solution might be as simple as not operating the fan when the child is sleeping.


Bedroom considerations

Because we spend so much time in bedrooms—typically 8 hours a night—bedrooms should be the healthiest rooms in the house. So, you may want to take more precautions there than in other rooms. For example, you may wish to reduce both magnetic and electric fields in the bedrooms but, to save money, you may only concentrate on magnetic-field reduction in the rest of the house. Electrically sensitive people often shut the power off to their bedroom at night to reduce electromagnetic fields to a minimum. This can be done easily by turning off the circuit serving that room at the main power panel (Be sure you aren’t also accidentally turning off something else that should be left running—like the refrigerator.), or by installing a demand switch on the bedroom circuit.


For years, electric blankets were made with a single wire woven into them in a serpentine fashion. This lead to strong magnetic fields whenever the blanket was turned on. (Waterbed heaters were made similarly.) In 1989, Sunbeam was the first to redesign their blankets, and other manufacturers soon followed. Sunbeam’s innovation was to simply run two wires in a serpentine fashion instead of one. By separating the wires by a mere 1/32", the fields in the wires cancel each other, resulting in a 95% reduction in field strength. But even reduced-field electric blankets can bathe your body in a 1-3 mG. field so, to be extra cautious, you may want to do without them completely. With waterbeds, you can unplug a heater having a strong magnetic field at night, when you’re in bed, then plug it back in during the day.


There are electrically conductive shielding fabrics on the market (Less EMF, Inc.) that can be grounded to minimize the strength of electric fields (but not magnetic fields). They are sometimes used under a mattress, or under the sheets of a bed, to minimize electric fields while sleeping.


What to look for outdoors

People are most concerned about outdoor power lines, but there are a number of other sources of electromagnetic radiation outside of a house that can affect the electromagnetic environment indoors. To be extra safe, houses should be at least a half mile from microwave transmission towers, radar installations, television and radio transmitters, and cellular phone towers. Some of these devices transmit a beam of electromagnetic radiation. For example, at airports, radar beams are aimed at incoming planes. A house should never be located within the path of such a radar beam. When in doubt, you should actually measure the fields to see if they are excessive. Most devices that act as receivers (such as home satellite dishes and television antennas) are not a problem.


Overhead power lines

Negative health effects associated with overhead power lines seem to have gotten far more press coverage, and generated far more public concern, than any other aspect of electromagnetic radiation. To understand just when they pose a risk, you must realize several things.


First, all power lines are not created equal—those carrying more voltage have higher fields than those carrying lower voltage. The most concern surrounds 500,000 volt (500 kilovolt [kv.]) and 765 kv. transmission lines. The 120 and 240 volt lines that bring power into our homes have much lower fields. High-voltage lines typically have wide utility easements, so houses are built some distance away from them—but sometimes not far enough away. And, just because you have low-voltage lines in your neighborhood doesn’t mean they are safe. One of the earliest electromagnetic-field studies found a higher incidence of leukemia when houses were near certain wiring configurations commonly found in neighborhoods.


The field strength near a particular power line will vary at different times of day, depending on how much current is being used. Magnetic-field strength will be highest on a hot summer day when everyone is using their air conditioner. To get the best understanding of your exposure, you should measure the field at least several times of day.


The strength of the field is strongest directly under a power line (because that’s where you’re most likely closest to it), and it diminishes as you move away from it. This explains why the interference you hear on your car’s radio is loudest directly under a transmission line. If two lines carry the same amount of current and voltage, and one is mounted on taller poles, or is further away from you, your exposure to its fields is less. Remember, all fields decrease with distance. So, just because a transmission line is visible doesn’t mean it’s dangerous.


Below are some typical magnetic-field measurements at different distances from power lines. These are the mean magnetic field strength as calculated for 321 power lines in 1990. The peak field strength (which occurs about 1% of the time) could be as much as twice as high as the mean strength, while the minimum field strength might only be half of the mean. All the measurements are in milligauss (mG.).


115 kv
230 kv
500 kv


The duration of your exposure is very important. For example, the magnetic field right next to an electric can opener in your kitchen could easily be over 1,000 mG., but it would only constitute a brief exposure. A much lower 10 mG. field in your bedroom, due to a nearby transmission line, is of much more concern, because you will be bathed in that 10 mG. for 8 hours or more.


There are several health considerations to keep in mind when designing and installing an electrical system in a house, but the most important thing is to minimize the danger of electrocution. Fortunately, this is adequately addressed by electrical codes and it is not a problem in most houses. Electromagnetic fields are another matter.


Exposure to electromagnetic fields is universal. In fact, we are all exposed to them, in varying strengths, every day. Yet a comprehensive understanding of their health effects is far from complete. Still, it is possible—and often relatively easy—to reasonably minimize your exposure. But, because there are so many variables, you cannot guess about electromagnetic field strength—you must actually measure the fields to get a true understanding of your exposure. You may be justifiably concerned about power lines in your back yard, or the wiring inside your house, but if you don’t measure the fields with a Gaussmeter, you will only be speculating—you won’t know for sure if your health is in any potential danger.


(This article is from the archives of the original Healthy House Institute, and the information was believed accurate at the time of writing. From “The Healthy House: How to Buy One, How to Build One, How to Cure a Sick One” © by The Healthy House Institute).


HHI Error Correction Policy

HHI is committed to accuracy of content and correcting information that is incomplete or inaccurate. With our broad scope of coverage of healthful indoor environments, and desire to rapidly publish info to benefit the community, mistakes are inevitable. HHI has established an error correction policy to welcome corrections or enhancements to our information. Please help us improve the quality of our content by contacting with corrections or suggestions for improvement. Each contact will receive a respectful reply.

The Healthy House Institute (HHI), a for-profit educational LLC, provides the information on as a free service to the public. The intent is to disseminate accurate, verified and science-based information on creating healthy home environments.


While an effort is made to ensure the quality of the content and credibility of sources listed on this site, HHI provides no warranty - expressed or implied - and assumes no legal liability for the accuracy, completeness, or usefulness of any information, product or process disclosed on or in conjunction with the site. The views and opinions of the authors or originators expressed herein do not necessarily state or reflect those of HHI: its principals, executives, Board members, advisors or affiliates.

Electrical Systems - Chapter 23:  Created on March 15th, 2012.  Last Modified on March 15th, 2012


We do not strictly control Google ad content. If you believe any Google ad is inappropriate, please email us directly here.



Information provided by The Healthy House Institute is designed to support, not to replace the relationship between patient/physician or other qualified healthcare provider.

Education Partners



Popular Topics: Air Cleaners & Air Purifiers | Allergies & Asthma | Energy Efficiency & Energy Savings | Healthy Homes | Green Building
Green Cleaning | Green Homes | Green Living | Green Remodeling | Indoor Air Quality | Water Filters | Water Quality

© 2006-2017 The Healthy House Institute, LLC.


About The Healthy House Institute | Contact HHI | HHI News & Media | Linking Resources | Advertising Info | Privacy Policy | Legal Disclaimer


HHI Info