Short circuit: Meaning (information, definition, explanation, facts)

A short circuit is a fault in an electrical apparatus whereby charge is allowed to flow between a phase and the electrical earth or between two phases. In less technical terms, a short circuit occurs when electricity moves through a circuit in an unintended direction, usually due to a connection forming where none was expected.

The simplest way to cause a short circuit is to connect the positive and negative ends of a battery together with a low-resistance conductor, like a wire. With low resistance in the connection, high current is generated, causing the cell to output a large amount of energy in a short time. (See also: Ohm's law, power)

In electrical devices, short circuits are usually caused when a wire's insulation breaks down, or when another conducting material (such as water) is introduced, allowing charge to flow along a different path than the one intended.

A large current through a battery (also called a cell) can cause the rapid buildup of heat, potentially resulting in an explosion or the release of hydrogen gas. Overloaded wires can also overheat, sometimes causing damage or fire to the wire's insulation. High current conditions may also occur with electric motor loads under stalled conditions, such as when the impeller of an electrically driven pump is jammed by debris.

Short circuits can be prevented by employing fuses, circuit breakers, or other overload protection, which disconnect the power in reaction to an excessive current. Wire sizes are specified in building and electrical codes, and must be carefully chosen for their specific application to ensure safe operation in conjunction with the overload protection.

In computer programming, short circuit is another name for minimal evaluation.

Short Circuit is the name of a 1986 movie starring Ally Sheedy and Steve Guttenberg, about a malfunctioning robot that "comes to life."