Chapter 02: 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.

Let’s begin:

Chapter Contents

Section 01

In a Nutshell

What are AC magnetic fields, in a nutshell? The quick and dirty.

Section 02

Learn More In-Depth

Learn more about AC Magnetic Fields and their possible dangers

Section 03

Measure Your Home Levels

Survey your home for EMFs: Hire an EMF Pro or DIY?

Section 07

Review the Measurements

How to review your magnetic field measurements.

Section 08

Take Action

Time to take the steps to reduce your magnetic field exposure.

Section 09

Footnotes & Final Thoughts

Chapter footnotes, links, case studies and a final thought.

Section 01:


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” to becoming aware of EMFs. 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 AC magnetic fields.

What are AC Magnetic Fields, In a Nutshell?

In a nutshell, AC magnetic fields are invisible waves of electromagnetic radiation that are present (and detectable) when electricity is being used.

These are man-made and caused by internal and external sources in and around homes and other buildings.

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.

Section 02:


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:

Deep Dive: A Primer on AC Magnetic Fields

If you’re interested, below is a video by Paul Anderson explaining how magnetic fields are cause by electrical current.

Magnetic Field of a Wire

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 largely have control over
  • C) internal sources that you have limited control over.

External Sources

External sources include the following:

  • overhead and underground power lines
  • electrical substations
  • stray current coming into homes on water pipes, cable TV wires and other utility lines
  • electric railways and subways are a less common source

Unfortunately, external magnetic fields can be extremely difficult and costly to shield against.

Internal Sources – Controllable

Less daunting, and more easily dealt with, 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
  • speakers

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 these sources when possible or, otherwise, to 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 a licensed electrician.


Other examples can be found throughout our EMF Field Guides and our Step-by-Step EMF Guides.

What Affects Magnetic Field Strength In Your Home

Amperage 02

How powerful the flow is. Amperage is defined as “the strength of an electric current expressed in amperes.”

Stray Current

Stray current will find its way into a home via metal water pipes and other grounding wiring such as cable TV wires.

Wiring Errors

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.

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The Electrical Grid

AC magnetic fields are a result of the electricity delivered from the electrical grid. In a perfect world, the electricity should be received from and then returned to the electrical utility only through the utility’s power lines.

In reality, this often doesn’t occur 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, check out the video below from Practical Engineering.04

Electricity was transformational for our society and it’s interesting to understand the delivery process.

How Does the Power Grid Work?

“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.”

Oram Miller03
Building Biologist and Electromagnetic Radiation Specialist

Health Concerns with AC Magnetic 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.

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 of the studies show unusual clusters of health disturbances nearby electrical substations and large transmission lines.

These are elevated levels from external sources, which are easily noticed when evaluating a home or neighborhood. Unfortunately, wiring errors within homes can cause similarly elevated levels and there’s no reason to think these 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.

In the next section are three studies of the non-thermal effects from AC magnetic fields. There are more in our appendix section on EMF Health Studies.

“Sleep is the golden chain that binds health and our bodies together.”

– Thomas Dekker

Deep Dive: AC Magnetic Field Health Studies


An interesting study on the effects of magnetic fields (along with electric fields) can be 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

A portion of the study abstract is below:

“Exposures to electric and magnetic fields and to potential occupational confounders were estimated through job exposure matrices. Odds ratios were elevated for hematopoietic malignancies with cumulative electric field exposure. After adjustment, the odds ratio for leukemia in the upper tertile was 4.45 (95% confidence interval (CI) 1.01-19.7). Odds ratios were also elevated for acute nonlymphoid leukemia, acute myeloid leukemia, and chronic lymphoid leukemia. For cumulative magnetic field exposure, there were similar elevations that fell with adjustment. Evaluation of the combined effect of electric and magnetic fields for leukemia showed significant elevations of risk for high exposure to both, with a dose-response relation for increasing exposure to electric fields and an inconsistent effect for magnetic fields.”

Another interesting study was done by Nancy Wertheimer and Ed Leeper titled, “Electric Wiring Configurations and Childhood Cancer.” From the abstract:

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

From the abstract:

The direct targets of extremely low and microwave frequency range electromagnetic fields (EMFs) in producing non-thermal effects have not been clearly established. However, studies in the literature, reviewed here, provide substantial support for such direct targets. Twenty-three studies have shown that voltage-gated calcium channels (VGCCs) produce these and other EMF effects, such that the L-type or other VGCC blockers block or greatly lower diverse EMF effects. Furthermore, the voltage-gated properties of these channels may provide biophysically plausible mechanisms for EMF biological effects.

To see additional reports on AC magnetic fields and other man-made EMFs, we’ve got more studies than you can shake a stick at over in our appendix 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.

Electromagnetic Hypersensitivity

Also known as EHS. While RF radiation is often believed to be the main cause of this, ELF AC Electric 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.

Section 03:


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:

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 decent readings of your magnetic field levels. We’ll go over some of these below in our DIY EMF section.

As with all EMF 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 electrical current coming from water pipes or other utility lines and then communicate these issues to an electrician.

DIY EMF surveying 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 an EMF consultant, 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 Chapter 09 – Contact an EMF Consultant or DIY?

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 measurements).

See our section on our recommended magnetic field meters below or visit our “The Best EMF Meters to Purchase in 2020” page to view other options or read our EMF meter reviews.

DIY – Selecting a Meter to Measure AC Magnetic Fields

As previously mentioned, AC magnetic fields are primarily measured using a gaussmeter.

Measuring properly with a gaussmeter 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.

Cornet ED88T Plus
Meter Review

NFA 1000
Meter Review

DIY – How to detect AC magnetic fields with an EMF meter

Due to the variety of models on the market it can be difficult to demonstrate the use of and address all the possible issues that gaussmeter owners may encounter.

Initially, we recommend that people read their EMF Meter manual thoroughly.  If there are still issues afterwards, we always recommend searching “How to use + EMF METER MODEL YOU PURCHASED” in both Youtube and your preferred search engine.

There are some great instructional videos from both the meter manufacturers and EMF consultants.

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.

Section 04:


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:

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 some of the most conservative you’ll come across.

Learn more about the Building Biology profession and their guiding principles.

Section 05:


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 your family’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
e) shielding

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 an expensive option.

– Picking up and moving. Sometimes the deck is stacked against you so much that it’s simply easier to relocate. Being directly beneath massive transmission lines may put you in this position.

Fixing Issues with Electrical Wiring Errors or Excess Current

Wiring errors, such as neutral-to-neutral and neutral-to-ground wiring errors, can cause formidable magnetic fields.

These will need to be fixed by a certified electrician. Having a trained EMF consultant to explain the problem and then test afterward (to ensure it has been properly dealt with) can be helpful.

Determine Which Furniture, Electronics, Appliances and Peripherals May Be Causing Increased Magnetic Fields

In our EMF Field Guides and Step-by-Step EMF Guides, we go over many items in your bedroom, office and family rooms that may be causing excessive exposure to AC magnetic fields.

This along with your gaussmeter survey will give you a good idea of what needs to be addressed.

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.

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 at Safe Living Technologies (use our promo code DIYEMF for 5% off, if purchasing).

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.

Section 06:


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 (coming soon).

A Final Note on AC Magnetic Fields

While external power lines are obvious sources of AC magnetic fields, the bedrooms and offices where people spend a majority of their time can also have some surprisingly high magnetic field levels from internal sources.

As a result, we always recommend testing for these fields and coming up with an exposure reduction plan should results be excessive.

Remember to visit our EMF Field Guides and our Step-by-Step EMF Guides to learn about many common, household sources of AC magnetic fields.

AC Magnetic Fields 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 – 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.

04 – 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,

05 – 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,

06 – 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,

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