Electric fields emanate from unshielded power lines, wires, equipment, and appliances.
Fortunately, electric fields can be shielded by grounded objects and materials including metal conduits, trees, and buildings. Magnetic fields also emanate from unshielded power lines, wires, equipment, and appliances. Therefore, high current loads such as transmission and distribution lines, transformers, feeders, switchgears, and heaters produce high magnetic field levels. A triple-axis gaussmeter has three separate magnetic probes placed on the x, y, and z axis. This meter electronically computes the vector sum of the directional components and displays the resultant on a digital readout.