This DVD graphically explains for electricians how certain wiring errors create high magnetic fields. It shows step-by-step methods of measuring the fields and then how to find the faulty circuit and the wiring error. Created under a grant from California Health Services to help school electricians reduce the magnetic fields found in the state's schools by a 90-school magnetic field survey. Filmed by the video department of Southern California Edison and using their graphics animation to show how the currents move in misconnected circuits. Written and hosted by Karl Riley, author of the book "Tracing EMFs in Building Wiring and Grounding". 23 minutes.