Magnetic fields in your home that do not originate from the local electrical grid can almost always be fixed. An elevated electromagnetic field will typically come from a wiring error or stray current on copper water pipes. For wiring errors, you will identify the problem circuits by doing continuity testing. You will then track down the exact location of the mistakes and then have an electrician correct them.
How Elevated Magnetic Fields Occur
If a circuit is wired properly, current will flow out on the hot wire and then an equal amount of current will flow back to the panel on the neutral. Both wires create a magnetic field. However, because they are equal and opposite, the fields cancel each other.
When the neutral wire is inadvertently connected to a separate circuit or ground, the return current won’t flow back to the panel the way it is supposed to. This will unbalance the current flow on the circuit and create a magnetic field around that wire. This field could be 2 to 10 mG (milligauss) and permeate through entire rooms of your home. This is an unhealthy situation for your family, as you can see in the following graph:
Image Credit: Ray Pealer
Using a Multi-Meter for Continuity Testing
The primary tool you will need for continuity testing is a multi-meter. This device allows you to send a small amount on current on the neutral wire of each circuit to test whether there is a properly closed loop.
Watch this short video to understand how a multi-meter continuity test works.
How to Do Continuity Testing to Find Wiring Errors
The first step is to turn off all the power to circuit panel. Then, one-by-one, you will lift the neutral wire of each circuit from the neutral bus bar. When you lift the neutral for a circuit, you will place one probe of the multi-meter on the neutral wire and the other on the bus bar. If the circuit is wired properly, the multi-meter should be silent because there is no continuity.
However, if the neutral wire is connected to the neutral or ground from another circuit (example at right), then the small pulse of current from the multi-meter will return to the panel and you will hear the sound. This means the circuit has a wiring error.
You will continue to do this for each neutral to find the other circuits that don’t pass the continuity test. There will typically be at least two circuits that are affected by the error. However, there could be multiple errors on several circuits. Most homes have one or two wiring errors.
Then you will figure out where in the home these circuits intersect. It could be at a light switch, light fixture or electrical socket junction box. Once you have identified where the errors likely exists, an electrician can typically find and fix the problem in very little time.
Hopefully this article takes the mystery out of fixing one common source of elevated magnetic fields in your home. If you would like help with process, please contact me to be introduced to an experienced EMF consultant that I trust. I can also answer your EMF questions through Zoom and email. You can read about my EMF consulting options here.
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