In an
electric power system
An electric power system is a network of electrical components deployed to supply, transfer, and use electric power. An example of a power system is the electrical grid that provides power to homes and industries within an extended area. The e ...
, overcurrent or excess current is a situation where a larger than intended
electric current
An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The movi ...
exists through a
conductor, leading to excessive generation of heat, and the risk of fire or damage to equipment. Possible causes for overcurrent include
short circuit
A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circu ...
s, excessive load, incorrect design, an
arc fault, or a
ground fault.
Fuses,
circuit breaker
A circuit breaker is an electrical safety device designed to protect an electrical circuit from damage caused by an overcurrent or short circuit. Its basic function is to interrupt current flow to protect equipment and to prevent the ris ...
s, and
current limiters are commonly used overcurrent protection (OCP) mechanisms to control the
risk
In simple terms, risk is the possibility of something bad happening. Risk involves uncertainty about the effects/implications of an activity with respect to something that humans value (such as health, well-being, wealth, property or the environm ...
s.
Circuit breakers, relays, and fuses protect circuit wiring from damage caused by overcurrent.
Related standards
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IEC 60364-4-43: Electrical installations of buildings – Part 4-43: Protection for safety – Protection against overcurrent
See also
*
Current limiting Current limiting is the practice of imposing a limit on the current that may be delivered to a load to protect the circuit generating or transmitting the current from harmful effects due to a short-circuit or overload. The term "current limiting" is ...
*
Electrical fault
In an electric power system, a fault or fault current is any abnormal electric current. For example, a short circuit is a fault in which a live wire touches a neutral or ground wire. An open-circuit fault occurs if a circuit is interrupted by a fa ...
*
Electrical safety
*
Overvoltage
When the voltage in a circuit or part of it is raised above its upper design limit, this is known as overvoltage. The conditions may be hazardous. Depending on its duration, the overvoltage event can be transient—a voltage spike—or per ...
References
Electrical systems
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