The Earth Circuit & The Basis for Grounding

I first learned about the Earth Circuit when i was reading through the second volume of the famous Feynman Lectures on Physics (“the red book”).

Every second, the Earth is part of a global electrical circuit (I like to call it the Earth Circuit), a quiet but powerful system spanning from the ground beneath your feet to the ionosphere roughly 31 miles above. This circuit is always on. And it’s the physical foundation for why grounding works.

In fair weather, there's a steady electric field near the surface of the Earth, typically around 100 volts per meter. That means if you're standing upright and barefoot, the top of your head is sitting at about 200 volts higher than your feet. But you don't feel it. Air is a poor conductor, so while the voltage exists, very little current flows.

When you're insulated from the Earth, wearing shoes, inside a car, in a building, your body floats at some intermediate voltage, shaped by the electric field around you. You’re no longer an electrical extension of the Earth. Instead, your body picks up voltage through capacitive coupling with the environment.

But the moment you touch the Earth, barefoot, or through a grounded conductor, your body becomes an extension of the planet’s surface. It’s as if you're part of a giant capacitor, clamped to zero volts. The head-to-foot voltage drop vanishes. The electric field can no longer push charge across your body.

This entire system is kept running by thunderstorms. Each day, thousands of lightning strikes deliver negative charges to the Earth, while the upper atmosphere is left more positive. These storms act like batteries, recharging the planet and keeping the earth circuit alive. At any moment, about 1 to 2 thousand amps of current are trickling down through the atmosphere and into the Earth.

Your body, when grounded, becomes part of that slow, global current. The amount of charge moving through you is tiny, measured in picoamps, but it's enough to reset your electrical state. The Earth is massive, conductive, and stable. It drains excess charge and buffers you against ambient electrical fluctuations.

Grounding is basic physics. The Earth has a potential. You’re either connected to it, or floating somewhere above it. Touching the Earth pulls your voltage to baseline and neutralizes the slow, random charge build-up that happens when you're disconnected.

In a world filled with electromagnetic interference and artificial insulation, grounding restores the body to its natural electrical reference point - the Earth itself.

As always, if you’re interested in learning more about grounding, check out Earth & Water.