Cancellation can also represent a viable and lower cost alternative to shielding for some commercial applications, and in other cases can be a useful adjunct. For net current problems in feeders or grounding conductors that cannot be resolved by conventional corrective practices, cancellation can sometimes be the solution. Although technical considerations often limit their applicability, there are many circumstances in which these systems can work effectively to produce a favorable result. EMF Services has performed pioneering work to address issues of elliptical field polarization, strong field gradients, inductive delay, and spatial phase variance, which have in the past precluded effective deployment of active field cancellation. We currently have systems installed and operating in many different parts of the country.
Some clarification is necessary to avoid confusion when discussing competing technologies.
There are basically three different approaches that have been taken to wide area magnetic field reduction. One approach uses a system which generates a random noise type of field that covers the area of concern. This field is superimposed on the undesired field, and according to its developers, counters any adverse biological effect. There appears to be some scientific evidence to support the concept, but at this point the benefits cannot be substantiated. The measured field level with the system activated is not reduced, and is actually slightly higher.