Ground and neutral

For uses of the term "grounding" or "earth" in electricity but not in the context of mains wiring, see ground (electricity).
"Neutral point" redirects here. For aircraft stability in pitch, see Longitudinal stability.
A shorting bar connecting ground and neutral in Swiss industrial building (outlined in red). A hunk of copper is visible that is designed to be easily connected or disconnected from its place between two screws, rated for 600 A (as stamped on it). We also see the thick wires in standard colors (two yellow/green ground and two blue neutral), as well as markings PEN (protected earth and neutral), PE (protective earth) and N (neutral). The three bars for the three "live" phases (marked L1, L2 and L3) are also visible on the bottom right.

In electrical engineering, ground and neutral (earth and neutral) are circuit conductors used in alternating current (AC) electrical systems. The neutral conductor returns current to the supply. To limit the effects of leakage current from higher-voltage systems, the neutral conductor is often connected to earth ground at the point of supply. A ground conductor is not intended to carry current for normal operation of the circuit, but instead connects exposed metallic components (such as equipment enclosures or conduits enclosing wiring) to earth ground. A ground conductor only carries significant current if there is a circuit fault that would otherwise energize exposed conductive parts and present a shock hazard. Circuit protection devices may detect a fault to a grounded metal enclosure and automatically de-energize the circuit, or may provide a warning of a ground fault.

Under certain conditions, a conductor used to connect to a system neutral is also used for grounding (earthing) of equipment and structures. Current carried on a grounding conductor can result in objectionable or dangerous voltages appearing on equipment enclosures, so the installation of grounding conductors and neutral conductors is carefully defined in electrical regulations. Where a neutral conductor is used also to connect equipment enclosures to earth, care must be taken that the neutral conductor never rises to a high voltage with respect to local ground.