earthgrounding

Earth grounding, or earthing, is the practice of connecting electrical installations to the earth through electrodes and conductors to establish a common reference potential and provide a low-impedance path for fault currents. The primary goals are safety—reducing shock risk by enabling protective devices to interrupt faults quickly—and stability, by keeping voltages within predictable limits during transient events.

Grounding typically involves a grounding electrode (such as a copper or steel rod driven into the soil, sometimes supplemented by plates or a network of rods), a grounding conductor that connects to service equipment or equipment frames, and bonding connections to create a uniform potential across metal components. Ground impedance is measured to ensure adequate fault current dissipation, with target values varying by jurisdiction but commonly described as 25 ohms or less in many systems.

Standards and practices governing grounding design, installation, and testing vary by region. In the United States, the National Electrical Code (NEC) Article 250 covers grounding and bonding; international and other national regulations often align with IEC 60364 or related standards. Additional measures may be used for lightning protection, electromagnetic compatibility, and specialized equipment, depending on the application.

Applications and safety considerations include power distribution, electrical installations in homes and industry, and telecommunications. Regular maintenance involves inspecting connections for corrosion, verifying soil conductivity, and confirming that protective paths remain intact. The terms grounding and bonding describe related but distinct concepts: grounding provides the path to earth, while bonding ensures conductive components share a common potential.