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Healthy Home Basics - Electrical Wiring

By HHI Staff

From The Healthy House Answer Book: Answers to the 133 most commonly asked questions. Questions 55-63.


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55. What are electromagnetic fields?


Electromagnetic fields, or EMFs for short, are invisible areas of energy. There are actually many different kinds. EMFs can be found around gamma rays, X-rays, ultraviolet light, visible light, infrared radiation, and radio waves. However, the kind most people are concerned about are the EMFs surrounding electrical wiring and appliances.


Anything that uses electricity will be surrounded with electromagnetic fields, of which there are two types—magnetic fields and electric fields. Just plugging something in will cause it have an electric field around it, but it must be operating (current must be flowing) to have a magnetic field.


Most researchers believe that electric fields are relatively benign, and that health effects are more likely to be related to magnetic fields. Magnetic fields are measured in units called milliGauss (mG), but there aren’t any well-established guidelines as to how much is too much. Still, it’s believed by most researchers that you should stay away from long-term exposures above 3 mG.


56. Can electrical appliances and the wiring inside my walls make me sick?


In most cases, probably not—but there are certainly situations where you should be concerned. The most common health effect researchers are looking into is cancer, but the evidence is often conflicting. In electrical occupations (electricians, linemen, etc.), some forms of cancer are seen more often than in workers who aren’t routinely around high-strength fields. And, some studies have found leukemia more often in people who live near high-voltage power lines.


There are three factors that determine how harmful an EMF exposure is: the strength of the field, your distance from the field, and your exposure time. Being near a high-strength field for many hours at a time is believed to be more serious than being near a high-strength field for a few minutes, or a low-strength field for an extended period of time.


To know for sure how strong a field is, you must measure it with a special device called a Gaussmeter. Gaussmeters are available from several mail-order or Internet-based companies. Fields vary considerably from one appliance to another, and they fluctuate at different times of the day. For example on a hot summer day, when everyone is using their air conditioner, there will stronger fields under outdoor power lines than on a cool fall evening when less electricity is being used.


You can often measure magnetic fields in the hundreds of mG very close to small electrical appliances (shavers, hair dryers, hand mixers, etc.). However, you don’t use these devices for hours on end, and the fields are often fairly weak a foot or so away. This is an important point to keep in mind—all electromagnetic fields get weaker as you move away from their source.


There can be high-strength magnetic fields around fluorescent-light ballasts, dimmer switches, power panels, electric heaters, electric stoves, TVs, computer monitors, and motors. Areas of high-strength fields are often called electromagnetic hot spots. One way to avoid very much exposure is to position furniture (especially beds) at a distance where the fields are reduced. In most homes, the hot spots only have a high-strength field that extends outward for a foot or two.


Magnetic fields are difficult to block. In fact, they’re rarely affected by walls. So, if you measure an electromagnetic hot spot near your refrigerator, you should consider what’s directly behind it on the opposite side of the partition wall. This is an important consideration that's sometimes overlooked.


If you live near high-voltage power lines, or an electrical substation, you can often have your electric utility measure the fields for you. They generally won’t measure the fields inside your home, and they usually contend that EMFs aren't a health problem. But, they often get a lot of phone calls about EMFs, so they usually have meters to measure fields around their own equipment. Where power lines are a problem, some people have moved their bed into a different bedroom—further away from the power lines to minimize their risk.


If you have electric radiant heat in your ceiling or if you have outdated knob-and-tube wiring in your house, they can bathe entire rooms in high-strength EMFs. Electric blankets can also be a problem, but most manufacturers have redesigned their products to have lower-strength fields than in the past. For more information about EMFs (and other indoor-air-quality issues), you can call the Environmental Health Clearinghouse at 800-643-4794.


57. Is it true that metal plumbing lines can contribute an EMF problem?


Yes, in some houses, this can be true. Electrical codes require that metal plumbing lines be grounded to minimize the danger of electrical shock. This is important, and an excellent thing to do. However, there are situations where the plumbing lines (or natural-gas lines) can actually be carrying a small amount of electricity. If this is the case, the metal pipes can be surrounded by magnetic fields.


These situations can be difficult to diagnose and fix, but it can be done. One thing that’s important to remember—you should never remove any plumbing-line grounding connections.


58. Can my house have an EMF problem because of something in my neighbor’s house?


That can occur. It usually happens when there’s a water-pipe grounding problem in one house, and two or more houses are interconnected by underground metal pipes. In some cases, high-strength EMFs throughout a neighborhood can be traced to a single problem in one house.
Electricians wishing to learn how to diagnose and solve EMF-grounding problems should get a copy of the book Tracing EMFs in Building Wiring and Grounding by Karl Riley.


59. What are some simple ways to minimize EMFs?


When you’re planning to build a new house, you should test the background EMF level on your site—if there are any power lines, substations, or transformers nearby. If high levels are found, you may want to reposition the house elsewhere on the lot. When the house is being wired, don’t locate the meter, power panels, or major power cables near the bedrooms because that’s where you'll be spending eight hours or so at a time. Make sure your home is properly grounded, and there is no current flowing on the water pipes. Because many appliances have high-strength fields, the easiest thing to do with them is to step away while they are operating. For example, you may want to sit farther away from your computer monitor, or move your clock radio to the other side of your night stand so it isn’t right next to your head.


Remember, all houses have electromagnetic hot spots. The goal is not to eliminate all of them. Rather, it’s to locate them in parts of the home where you don’t spend a great deal of time. For example, even though you might walk by a power panel in a hallway several times a day, that’s better than having it next to your head while you're sleeping in bed.


60. What is electromagnetic sensitivity?


Recently, the term electromagnetic sensitivity has emerged. People with this condition are negatively affected by EMFs at lower field strengths than the rest of us. They sometimes report dizziness, ringing in the ears, muscle weakness, confusion, fainting, or other symptoms. Electromagnetic sensitivity doesn’t seem to be as common as chemical sensitivity, but some people are affected by both. The Electromagnetic Sensitivity Handbook by Lucinda Grant is a good source for information on this condition.


61. What can an electromagnetically sensitive person do to make his or her home safer?


Unfortunately, some people with electromagnetic sensitivity have had to avoid electricity completely. However, many get relief by reducing their exposure considerably. For example, they may sit farther away from their computer screen than they did previously. Some have reverted to using a manual typewriter. One thing that often helps is to turn off the circuit breaker at the power panel that serves the bedroom before going to bed. If you do this, make sure you aren’t accidentally turning something important off—like the refrigerator.


62. Can’t metal siding on a house cause EMF problems?


This is something we’re asked about quite often even though, as it turns out, it's unlikely to be a problem. The idea dates back to 1980, when a book dealing with indoor pollution said that a metal-sided house would act like a Faraday cage and interfere with a person’s natural biologic rhythms—such as their waking/sleep pattern.


A Faraday cage is a special room that electrical technicians sometimes use to evaluate equipment or perform tests in. It usually has well-grounded metal screen on all sides, top, and bottom, and it’s designed to block out all forms of radiation. As a result, there’s no electrical interference of any kind inside the room.


If a person spends an extended period of time in a Faraday cage (several days or a few weeks), their body gets out-of-sync and their natural rhythms start functioning differently. This is because a Faraday cage blocks out the weak naturally occurring background electromagnetic radiation that regulates our systems. The human species has been surrounded by this natural beneficial radiation for tens-of-thousands of years.


While a metal-sided house may, at first, seem like a Faraday cage, it really isn’t. In fact, it would be very difficult for a home to duplicate the same conditions inside a real Faraday cage. For example, there couldn’t be any windows, doors, or other openings. In addition, all the individual pieces of metal siding would need to be soldered together, there would need to be a metal roof and a metal floor, and everything would need to be securely grounded. Even if all that was done, a person would need to remain indoors, because going outside would cause their rhythms to be restored.


63. I’m bothered by the odor of plastics. Will plastic-jacketed electrical wiring be a problem for me?


It could be—especially if you’re directly exposed to new wire. It’s possible to minimize outgassing by running the wiring inside metal conduit—but this isn’t often done in residences because it can be expensive. What we recommend is to buy the wiring early in the construction process and let it air out before it’s installed. Some people have had it sitting in a garage for several months while other work is being done on the house.


Once the walls are covered with wallboard, the wiring isn’t exposed to the living space. So, it usually isn’t a problem. But for sensitive people—just to be extra safe—we usually suggest that it be wrapped with household aluminum foil to reduce outgassing inside the walls.


(Note: This article is part of the original HHI Archives, and was believed to be accurate at the time of writing. The views expressed in this article are those of the author, and do not necessarily represent those of The Healthy House Institute, LLC.)


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Healthy Home Basics - Electrical Wiring:  Created on February 3rd, 2008.  Last Modified on February 28th, 2011


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