Throughout this country, and for that matter, throughout the world, is(are) the common reference point for all electrical systems.

Question

Quizplus · Accepted Answer

The earth serves as the common reference point, or ground, for all electrical systems. This is because the earth has a virtually zero potential and can thus absorb excess electrical charges or provide a return path for electrical currents. A standard metal plate or individual building walls may be used as grounding electrodes, but they ultimately connect to the earth to serve as the reference point. The atmosphere is not a suitable reference point as it is highly variable in its electrical properties.

Throughout This Country, and for That Matter, Throughout the World