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 a Swiss industrial building (outlined in red). A piece of copper is visible that is designed to be easily connected or disconnected from its place between two screws for testing purposes, rated for 600 A (as stamped on it). Also visible are 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 phase lines (marked L1, L2 and L3) are also visible on the bottom right.

In electrical engineering, ground (or earth) and neutral are circuit conductors used in alternating current (AC) electrical systems. The neutral conductor carries alternating current (in tandem with one or more phase line conductors) during normal operation of the circuit. By contrast, a ground conductor is not intended to carry current for normal operation, but instead is present for safety: it connects exposed conductive parts (such as equipment enclosures or conduits enclosing wiring) to earth (the ground), and carries significant current only in the event of a circuit fault that would otherwise energize exposed conductive parts and present a shock hazard. In such case the intention is for the fault current to be large enough to trigger a circuit protective device that will either de-energize the circuit (via a fuse or circuit breaker) or provide a warning. 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.

Significant voltage unintentionally appearing on exposed conductive parts of an electrical installation can present danger, so the installation of ground and neutral conductors is carefully regulated in electrical safety standards. Under certain strict conditions the same conductor may be used for providing both ground and neutral functions together.