Chapter 03: The Beginner’s Guide to
AC Magnetic Fields
In this chapter, you’re going to learn all about AC magnetic fields.
You’ll learn how and why they occur and what you can do to lessen your exposure to these man-made EMFs.
We share the two main ways that elevated AC magnetic fields become present in your home.
What are AC magnetic fields, in a nutshell? The quick and dirty.
Learn more about AC Magnetic Fields and the possible dangers
Survey your home for EMFs: Hire an EMF Pro or DIY?
What are AC Magnetic Fields, In a Nutshell?
Below we give you the quick and dirty rundown on AC magnetic fields.
Magnetic fields are, in some sense, a “gateway” EMF. People are instinctively wary of overhead transmission lines and this, in turn, leads them to learn more about them and the magnetic fields the lines produce.
While power lines are an obvious source, these aren’t the only way you and your family can be exposed to the phenomenon of AC magnetic fields.
What are AC Magnetic Fields, In a Nutshell?
In a nutshell, AC magnetic fields are invisible fields of electromagnetic radiation.
These are man-made and are caused by internal and external sources in and around homes and offices.
If you have nearby power lines, home wiring errors or devices plugged in and drawing electrical current, you will have the presence of magnetic fields.
Almost all of us will have some exposure to these.
Unfortunately, at elevated exposure levels, some scientists and physicians believe these can cause health issues.
So, it’s a good idea to do some testing and make sure there aren’t abnormally high fields in parts of your home.
More on how to do this below.
Learn More About AC Magnetic Fields
Interested in learning more about AC magnetic fields?
In this section we’ll go over some of the common internal and external sources of magnetic fields you may encounter in and around your home.
Some of these field sources are sure to surprise you:
Common Sources of AC Magnetic Fields
As mentioned, AC magnetic fields are invisible waves of electromagnetic radiation and are present and detectable when electricity is flowing or being used.
There are three common sources of AC magnetic fields:
- A) external sources,
- B) internal sources that you have considerable control over
- C) internal sources that you have limited control over.
External sources include the following:
- overhead and underground power lines
- electrical substations
- stray current coming into homes on water pipes
- stray current on cable TV wires
- stray current on other grounding system components
- electric railways and subways are a less common source
Unfortunately, external magnetic fields can be extremely difficult and costly to reduce or eliminate.
Internal Sources – Controllable
Less daunting and more easily mitigated are controllable internal sources of magnetic fields. Some examples of these are:
- dimmer switches
- wired alarm clocks
- appliance electronics
- appliance motors and fans
- electrical wiring errors
These point sources are often located in frequented parts of houses, such as bedrooms, kitchens, living rooms and home offices.
We encourage people to remove or keep a safe distance from these magnetic field sources.
Internal Sources – Limited Control
Lastly, internal sources that you have limited control over are primarily the electrical wiring errors within a buildings walls.
These can be identified and repaired with the help of an EMF consultant and/or a licensed electrician.
Many more examples can be found in our guide 199+ Common Sources of EMFs.
What Affects Magnetic Field Strength In Your Home
How powerful the flow is. Amperage is defined as “the strength of an electric current expressed in amperes.”
Stray current will find its way into a home via metal water pipes and other grounding wiring such as cable TV wires.
These include wiring errors such as neutral to ground and neutral to neutral wiring.
The farther the distance from the source of the magnetic field, the lower the field reading will be.
The Electrical Grid
Similarly to AC electric fields, AC magnetic fields are a result of the electricity delivered from the electrical grid. In a perfect world, the same amount of electricity should be received from and then returned to the electrical utility through the overhead/underground power lines.
Interestingly, this unfortunately often isn’t the case and can lead to elevated AC magnetic field levels within the home. More on this later in the chapter.
For those of you that are interested in learning more about how electricity is distributed from power plants to your front door, please see Appendix 01 – The Electric Grid. Electricity was transformational for our society and it’s interesting to understand the delivery process.03
“Magnetic fields, particularly from 60 Hz AC building wiring, are a known cancer risk, and when magnetic and electric fields are both present in sleeping areas, the cancer risk is reported to be eleven times higher than with either alone.”
Building Biologist and Electromagnetic Radiation Specialist
Health Concerns with AC Magnetic Fields
As with AC electric fields, there’s no current, open and shut epidemiological study that conclusively proves that AC magnetic fields cause harmful biological effects. However, there are multiple studies that detail the possible risks of being in proximity to excessive man-made magnetic fields.
Some show unusual clusters of health disturbances nearby electrical substations and large transmission lines. There’s no reason to think that wiring errors in a home or office that cause massive magnetic fields wouldn’t have similar detrimental health effects.
At a minimum, it’s likely that having magnetic fields pulsing around you at night will affect the quality of your sleep. As we covered in the previous section on electric fields, sleep is an incredibly important restorative time for humans and pets and its disruption can be a catalyst for health problems.
Building Biologists advise keeping magnetic field levels as low as possible for the probable betterment of your sleeping cycles.
“Sleep is the golden chain that binds health and our bodies together.”
– Thomas Dekker
AC Magnetic Field Health Studies
Below are three studies of the non-thermal effects from AC magnetic fields. There are more in our section on EMF Health Studies.
EPIDEMIOLOGICAL STUDIES OF AC MAGNETIC FIELDS
One of the more interesting studies on the effects of magnetic fields (along with electric fields) was a study found in the American Journal of Epidemiology titled “Leukemia following Occupational Exposure to 60-Hz Electric and Magnetic Fields among Ontario Electric Utility Workers.”04
Another interesting study was done by Nancy Wertheimer and Ed Leeper titled, “Electric Wiring Configurations and Childhood Cancer.” The abstract of the study reads as follows:
An excess of electrical wiring configurations suggestive of high current-flow was noted in Colorado in 1976–1977 near the homes of children who developed cancer, as compared to the homes of control children. The finding was strongest for children who had spent their entire lives at the same address, and it appeared to be dose-related. It did not seem to be an artifact of neighborhood, street congestion, social class, or family structure. The reason for the correlation is uncertain; possible effects of current in the water pipes or of AC magnetic fields are suggested.05
A third study of interest was Martin Pall’s study “Electromagnetic fields act via activation of voltage-gated calcium channels to produce beneficial or adverse effects.” 06
To see additional reports on magnetic fields, we’ve got more studies than you can shake a stick at over in our section on EMF Health Studies.
Recap of Possible AC Magnetic Field Health Concerns
Leukemia in High Risk Occupations
Read more about this in the Ontario Electric Utility Workers study above.
Voltage Gated Calcium Channels
Read more about this in the Martin Pall study found above.
Also known as EHS. While RF radiation is often believed to be the main cause of this, ELF AC Magnetic Fields may be a contributing factor.
Melatonin & Sleep Disruption
The theory goes that magnetic fields may lead to less melatonin production and result in poorer and less regenerative sleep.
Learn How to Measure Magnetic Fields
We’ve gone over why you’d want to measure magnetic fields.
Now let’s go over how these fields are measured.
We’ll also go over whether you should hire an EMF professional or do the measurements yourself
Let’s get started:
How AC Magnetic Fields are Measured
A gaussmeter is the main tool used to discover and measure magnetic fields. The magnetic fields are measured in milligauss or nanoteslas.
There’s a large selection of gaussmeters on the market to choose from. Many of the meters are dual-use or triple-use, as they are combined with field voltage meters (for electric field measurement) and RF meters (for radio frequency measurement).
In addition to the gaussmeters, a more rudimentary tool called a “buzzstick” can help identify the location of magnetic fields.
Testing Your Home: Contact an EMF Pro or DIY?
AC magnetic fields are not difficult to test for and there are reasonably priced entry-level gaussmeters that can give you a decent approximation of your magnetic field levels. We’ll go over some of these below in our DIY EMF section.
As with electric field measurements, the benefit of hiring EMF consultants is they will provide extensive experience and training, professional-grade meter accuracy and will help you determine and move forward with an appropriate EMF mitigation program.
Perhaps the main advantage of utilizing an EMRS or BBEC for the magnetic field survey is that they can help pinpoint any potential wiring errors or any excess current coming from water pipes or other utility lines and then communicate these issues to an electrician.
DIY EMF surveying, with the help of this guide, is less costly, but may take longer and be out of the comfort zone for some people. There’s also no reason that you can’t do some of the work yourself in concert with EMF consultants, too.
Most EMF consultants will have reasonable hourly phone consultation rates. Here are some remote EMF consultants if you’re interested and don’t have a local professional.
To better appreciate the pros and cons of contacting an EMF professional vs. doing-it-yourself, please see our page titled, “Contact an EMF Consultant or DIY?“
DIY – Selecting a Meter to Measure AC Magnetic Fields
As previously mentioned, AC magnetic fields are primarily measured using a gaussmeter and a “buzzstick” can also be used for rudimentary assessments.
Measuring properly with a gaussmetter can give you an accurate assessment of your magnetic field exposure, which in turn allows you to draw up a mitigation plan.
One of our recommended entry-level AC magnetic field gaussmeters is the Trifield TF2 EMF meter. Read our review of the Trifield TF2 in Appendix 05: Recommended EMF Meters.
The Trifield TF2 and two of the other entry-level alternatives (the Cornet ED88T and the Meterk gaussmeter) can be seen below.
DIY – How to detect AC magnetic fields with an EMF meter or Buzzstick
Please visit our individual pages to learn “How to detect AC magnetic fields with an EMF meter” (coming soon) and “DIY – How to use a buzzstick to detect AC magnetic fields” (coming soon) to learn how to survey your home or work for magnetic fields.
Review Your Magnetic Field Measurements
Okay, so you’ve taken magnetic field measurements or had an EMF pro do it for you.
Now what do the readings mean?
Next, we’ll give you international and domestic standards from which to compare your readings
Let’s dive in:
DIY – Worksheets to Use When Taking Magnetic Field Measurements
We offer printable PDFs of worksheets to record your magnetic field measurements and other EMFs to those readers that support our cause by purchasing a PDF or kindle version of the Beginner’s Guide to EMFs. It makes a great gift for those family members that may be unaware of what EMFs are or how the fields may be affecting them.
Please consider supporting this worthy cause by purchasing this EMF Guide (PDF, Kindle or eReader) or providing us with a small donation.
Understanding the results of your AC Magnetic Field study
Below are the Building Biology guidelines for magnetic fields in sleeping areas. You can read the original PDF here.
The good folks over at Safe Living Technologies also have an Education section with Building Biology and International EMF Guidelines that you can download and use as a reference.
It’s important to note that these are specific recommendations for sleeping areas. The Building Biology field views bedrooms and sleeping areas as especially important due to the restorative nature of sleep. As such, the guidelines are the most conservative.
Learn more about the Building Biology profession and their guiding principles.
Take Action to Reduce Your Magnetic Field Exposure
You’ve taken measurements and reviewed the results.
Now it’s time to take action.
In this section we’ll give you some actionable tips on how to lower your exposure to magnetic fields.
Let’s get started:
Take Action: Reduce or Eliminate
Taking action in reducing you, your family’s and your pet’s exposure to AC magnetic fields often takes the form of five steps:
a) creating distance from external magnetic field sources
b) fixing issues with electrical wiring errors or excess current
b) removal of electronics, tech and computer peripherals
d) creating distance from internal magnetic field sources
Creating Distance from External Sources
The magnetic fields from power lines or electrical substations are notoriously hard to shield against, so the best plan often is to simply create distance. This can mean the following:
– Moving beds, desks and couches to opposite sides of a frequented room or across the house itself.
– Paying the local electrical utility to bury or reroute powerlines. This is obviously not a cheap proposition.
– Picking up and moving. Sometimes the deck is stacked against you so much that it’s simply easier to relocate.
Fixing Issues with Electrical Wiring Errors or Excess Current
Wiring errors, such as neutral-to-neutral and neutral-to-ground wiring errors, are located by the formidable magnetic fields they cause.
These will need to be fixed by a certified electrician. Having a trained EMF consultant to explain the problem and then test afterwards to ensure it has been rectified can be helpful.
Determine Which Furniture, Electronics, Appliances and Peripherals May Be Causing Increased Magnetic Fields
Creating Distance from Internal Sources
Internal sources of AC magnetic fields can be refrigerators, circuit breaker boxes, heaters, air conditioning units, wired alarm clocks, appliance electronics and fans.
Magnetic fields fall off at a fairly quick rate, so creating distance can often be a very effective means of lowering the exposure of you, your family or your pets.
Shielding AC Magnetic Fields
As mentioned previously, shielding interior and exterior AC magnetic fields can be difficult.
Shielding of interior sources, such as refrigerators, heating and air conditioning units and circuit breaker boxes is most commonly attempted through the use of a product called G-iron Flex. G-iron Flex is applied in rolls and is most effective when used in close proximity to the magnetic field source. Learn more about G-iron flex and Magnetic Field Shielding (coming soon).
Overhead and buried powerlines can be shielded against through the use of a process called “active cancellation.” To learn more about this, please visit our “Active Cancellation of Magnetic Fields” page.
In Conclusion: Case Studies, Resources, & Footnotes
Below are some final thoughts we have on AC magnetic fields
There’s also some interesting AC magnetic field resources below.
We’ve included a few case studies that EMF Experts have experienced in the field. These make for an interesting read, as well.
Lastly, we’ve added all the footnotes from the chapter.
Stories from EMF Specialists – EMF Case studies
We’ll have these up shortly.
Many of these experts are available for remote EMF consulting via Telephone/Zoom/Facetime/Skype and can be extremely helpful in locating problematic areas of electromagnetic exposure.
EMF Resources – AC Magnetic Fields
To learn more about EMF research and epidemiological studies, many dealing with AC magnetic fields, please visit Chapter 20 – EMF Learning Resources.
A Final Note on AC Magnetic Fields
AC magnetic fields are the 2nd most talked about member of the Four Fields to Forgo and always important to measure for. The external power lines are easy to spot, but the bedrooms and offices where people spend a majority of their time can also have surprisingly elevated magnetic field levels.
As a result, we always recommend testing for these fields and coming up with a mitigation plan should results be excessive.
Please view our guide, 199+ Common Sources of EMF Exposure, to learn about many common, household sources of AC magnetic fields.
AC Magnetic Field Chapter Notes
01 – Field Strength
This can vary greatly depending on the source of the AC magnetic fields. Some electrical transmission lines and internal wiring errors can produce substantial magnetic fields.
02 – Amperage and Magnetic Fields
Amperage is another way of saying electrical flow or, more simply, the utilization of the electricity.
03 – The Electrical Grid
The manner in which electricity is produced and distributed, so that you can watch your TV or effortlessly heat you home, is an interesting process. We cover it in our Appendix Page: The Beginner’s Guide to the Electrical Grid. (coming shortly)
04 – Oram Miller
Oram’s website Create Healthy Homes is a wealth of information into all facets of EMF exposure and how to mitigate those risks. Highly recommended.
05 – Ontario Hydro Workers Study
Anthony B. Miller, Teresa To, David A. Agnew, Claus Wall, Lois M. Green; Leukemia following Occupational Exposure to 60-Hz Electric and Magnetic Fields among Ontario Electric Utility Workers, American Journal of Epidemiology, Volume 144, Issue 2, 15 July 1996, Pages 150–160, https://doi.org/10.1093/oxfordjournals.aje.a008902
06 – Childhood Cancer Study
Nancy Wertheimer, Ed Leeper; Electrical Wiring Configurations and Childhood Cancer, American Journal of Epidemiology, Volume 109, Issue 3, March 1979, Pages 273–284, https://doi.org/10.1093/oxfordjournals.aje.a112681
07 – VGCC Study
Martin Pall; Electromagnetic fields act via activation of voltage-gated calcium channels to produce beneficial or adverse effects, Journal of Cellular and Molecular Medicine, Volume 17, Issue 8, 2013, Pages 958-965, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3780531/#
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Beginner's Guide to EMFs
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