The US power grid is overloaded. Each outlet in each room is connected to every other outlet and rooms in the home. Your home is connected to your neighbor’s home and so forth & so on. Every single device that we use generates dirty electricity (with the exception of motors & incandescent bulbs) that gets put back into the wires as they return to the substation. This meter will help you identify the outlets that are hot. Under 50 GSU, the outlet is safe. Over 50 GSU, high frequencies are arcing into your living space & are biologically active.