Ground (electricity)

Electrical ground is a chosen reference potential in a circuit or a conductive connection to Earth. Its meaning depends on the circuit and does not always imply zero voltage or an Earth connection.

Reference potential: A selected voltage level against which other electrical potentials are measured. Circuit ground commonly sets this reference, often assigned zero volts by convention.
Electric potential: The electrical potential energy per unit charge at a point in an electric field. Ground names a selected potential, not an absolute electrical zero.
Electrical bonding: The joining of conductive parts to ensure electrical continuity and limit voltage differences between them. Bonding links enclosures and conductors so ground connections behave predictably.
Neutral (electrical wiring): A circuit conductor connected to the supply neutral point and intended to carry current during normal operation. Neutral may be bonded to Earth at a designated point but is not interchangeable with ground.
Ground loop: An unintended circulating current caused by voltage differences between points connected through multiple ground paths. Multiple ground connections can create these loops and introduce noise.
Voltage: The difference in electric potential between two points. Circuit voltages are measured relative to a ground reference.
Grounding system: The network of conductors and electrodes connecting an electrical installation to Earth. It provides the installation’s deliberate Earth connection and fault-current route.
Isolated ground: A grounding arrangement that separates selected equipment-grounding conductors from other grounding paths until a defined connection point. It addresses noise concerns without making the circuit reference universally separate from Earth.
Protective earth: A safety conductor that connects exposed conductive equipment parts to Earth to limit dangerous touch voltages. It is an Earth connection used for safety, distinct from a circuit’s voltage reference.
Electric current: The rate at which electric charge passes through a surface. Ground conductors can carry return current, not merely establish a reference.

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