Ground Rules
The Integrated Systems Bonding Project
The Earth
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The facility has a special relationship with the Earth. All facilities provided with electrical utility service are connected directly to the Earth through one or more grounding electrodes, one grounding electrode system (GES), and one (or two in parallel) grounding electrode conductor (GEC). There is a continuous exchange of voltage and current flow back and forth across all these, balancing, pooling, and refreshing the electrons along the conductors.
The Earth has both noisy and quiet regions. This is due to uneven distribution of elements, especially metallic ones.
Fe - Iron and Al - Aluminum are among the top ten most abundant elements on Earth. Accordingly, these affect geomagnetism and current flow.
Zones of widely distributed metals will tend to be quiet because current flow is widely and uniformly distributed across the mass, leaving voltage weak in magnitude.
Zones of narrowly distributed metals will tend to be noisy because of concentrated current flow building voltages up to a strong magnitude. This is similar to how electrical circuits work.
Many forces cause the Earth to move, both underground and aboveground where people and facilities are found. Specific forces include seismic activity like earthquakes and volcanic eruptions, as well as tectonic plate movement and shifts. Tectonic plates are known to travel at speeds of 0 to 100 mm per year. Lesser-known forces that cause earth movement include flooding, landslide, mudslide, and even wildland fire.
The interior of the Earth is radioactive and generates heat that rises toward the surface, produced mostly from the radioactive decay of uranium and other elements in the crust and mantle. Together, U - Uranium and Th - Thorium generate 90 percent of Earth's heat. This heat creates a movement of elements and materials through the core and mantle of the Earth. Convective cells form in association with this movement, and generate the Earth's magnetic field as well as current flow underground.
Another earth-moving force is gravity, manifested from large objects, the Earth, our Moon, and our Sun. Each day the earth may move as much as one foot up and down in response to these forces.
Earth movement affects facilities and structures by placing extra stress on them. This causes electrical disconnects to occur, such as missing ground and other hazards. For example, a foundation may shift and walls may split. Electrical conduit may be pulled apart and wires stretched or broken outright.
The Earth and the facility are connected through a GES, which passes current flow between them along a GEC. Current balances, pools, and refreshes evenly across all points along the GEC pathway. Noisy and quiet regions influence current flow underground.
Besides influencing geomagnetism and underground current flow, earth movement places physical stress on facilities that can result in hazards such as missing ground.
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