Electromagnetic Fields (EMFs)

Mike Holt was contacted recently by two different people with similar problems:

“I am having a lot of trouble with the EMFs in my house in California and I would really appreciate getting some help ASAP. Our house is particularly challenging for me because we run so much electrical equipment. My husband works in technology and our house is about as wired as anyone’s could be. Sadly, it is affecting my health and so the sooner we can deal with this the better.”

“I am writing to you today as something of an act of desperation. I have recently purchased a house which due to poor wiring, has very high EMF fields (>30mg) in one corner of the house (directly above the fuse box and we believe one small junction box). I have been looking for an electrician / electrical engineer in the Portsmouth, NH area, who might know how to rectify this.”

What does "EMF" mean for an electrician?

Karl Riley explains:

For us we limit use of the term to the power frequency band that we deal with (50/60 Hz plus harmonics). And it is the magnetic field component that is active since it can induce currents in conductors within the field area. Inside a transformer, it is by way of this action that all power is transmitted from the primary coil to the secondary. The magnetic field strength emitted by a conductor is directly related to the amps in the conductor, no matter what the voltage. However, in a cable which is wired according to NEC rules, current is always running in two or more opposite directions with equal amperage. Thus the magnetic field from the hot conductor is cancelled by the equal magnetic field coming out of the neutral. Three-phase works similarly, with the phases canceling out each other’s magnetic fields, with the neutral conductor's field automatically balancing any unequal amps from the phases.

Troubleshooting is needed when the required cancellation does not take place, and the magnetic field spreads out and induces current in any conductors within range, from electronic instruments to the human body, which happens to function by electrical signals. A gaussmeter shows the field strength, or an electro-sensitive person complains, and now there is a need for an "EMF Expert". But all that is needed is an electrician who can use a few instruments to trace down where the source conductor got unbalanced. Where did the balancing current get diverted from its dedicated path? Where did the violations of NEC 310-4 or 300-3(b) occur? It is almost 100% a diversion of neutral current to either another neutral from another circuit or to a grounding path. And when a service panel is grounded to a metallic water service pipe, neutral flows with no balancing counter-current, on its way back to the transformer. The "EMF Expert" should be able to understand the electrical principles involved, and be able to use the correct instruments to find the location (such as a switch box or junction box) where the incorrect connection was made. And when grounding to a metal water pipe is involved, he/she should know what can be done, according to NEC, to stop this parallel current and re-establish a balanced Service cable (a plumber is involved).

Karl Riley is an EMF consultant with 25 years’ experience in identifying sources of elevated magnetic fields in buildings. He also designed and produced an accurate gaussmeter with a flexible probe. His book "Tracing EMFs in Building Wiring and Grounding", first published in 1995 is now in its third edition (2012). It continues to be the definitive practical troubleshooting guide for reducing magnetic fields due to wiring errors and grounding practices, written for the electrician, contractor, architect, inspector, utility engineer, safety engineer, and do-it-yourself remodeler. His book is based on the finding that the most common sources of AC magnetic fields over 3 mG in substantial areas of living space are mis-wired circuits and legal but correctable grounding currents. The book explains in detail how to detect National Electrical Code violations, trace, and correct them. It provides an evaluation of building grounding practices with recommended low-field alternatives which meet the Code. You can reach Karl at kriley3@earthlink.net

Are you an expert on EMFs? If you are an expert on EMFs please email us at info@mikeholt.com and include your credentials and contact information. We will list your information on our EMF web page, and also on the Mike Holt “Find an Expert” webpage.

Related Links

Karl Riley’s EMF Video [22:31]

Mike Holt EMF Articles

Mike Holt EMF Newsletter Archive:

EMF Safety Network

Tracing EMFs in Building Wiring and Grounding Paperback – March 19, 2012 by Karl Riley