Monday, July 27, 2015
Plumbing current magnetic fields EMF from water pipes
The most common source of elevated magnetic field readings (high EMF) in homes is electrical current on a water pipe. This is more accurately described as neutral current diversion into a metallic plumbing and grounding system, also referred to as plumbing current, or ground current. Small commercial buildings can also exhibit this condition. The situation exists when some of the current that would normally return through the electrical service line feeding the building is instead channeled into the grounding system, where it returns to the transformer by way of alternate paths, including water pipes, the public water main, and neighboring residences. This unbalanced current creates a strong magnetic field with a wide spatial extent. The type of power distribution system used in the U.S., in combination with important National Electrical Code grounding requirements, establish the underlying conditions for this problem to occur. It is more common in communities with moderate to high housing density, especially those served by overhead power distribution lines, but it can occur anywhere.