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 circuit. The opposite of a short circuit is an open circuit, which is an infinite resistance (or very high impedance) between two nodes.
Tree limbs cause a short circuit, triggering an electrical arc during a storm
A short circuit is an abnormal connection between two nodes of an electric circuit intended to be at different voltages. This results in an electric current limited only by the Thévenin equivalent resistance of the rest of the network which can cause circuit damage, overheating, fire or explosion. Although usually the result of a fault, there are cases where short circuits are caused intentionally, for example, for the purpose of voltage-sensing crowbar circuit protectors.
In circuit analysis, a short circuit is defined as a connection between two nodes that forces them to be at the same voltage. In an 'ideal' short circuit, this means there is no resistance and thus no voltage drop across the connection. In real circuits, the result is a connection with almost no resistance. In such a case, the current is limited only by the resistance of the rest of the circuit.
Examples
A common type of short circuit occurs when the positive and negative terminals of a battery are connected with a low-resistanceconductor, like a wire. With a low resistance in the connection, a high current will flow, causing the delivery of a large amount of energy in a short period of time.
A high current flowing through a battery can cause a rapid increase of temperature, potentially resulting in an explosion with the release of hydrogen gas and electrolyte (an acid or a base), which can burn tissue and cause blindness or even death. Overloaded wires will also overheat causing damage to the wire's insulation, or starting a fire.
In electrical devices, unintentional short circuits are usually caused when a wire's insulation breaks down, or when another conducting material is introduced, allowing charge to flow along a different path than the one intended.
In mains circuits, short circuits may occur between two phases, between a phase and neutral or between a phase and earth (ground). Such short circuits are likely to result in a very high current and therefore quickly trigger an overcurrent protection device. However, it is possible for short circuits to arise between neutral and earth conductors and between two conductors of the same phase. Such short circuits can be dangerous, particularly as they may not immediately result in a large current and are therefore less likely to be detected. Possible effects include unexpected energisation of a circuit presumed to be isolated. To help reduce the negative effects of short circuits, power distribution transformers are deliberately designed to have a certain amount of leakage reactance. The leakage reactance (usually about 5 to 10% of the full load impedance) helps limit both the magnitude and rate of rise of the fault current.
A short circuit may lead to formation of an electric arc. The arc, a channel of hot ionized plasma, is highly conductive and can persist even after significant amounts of original material from the conductors has evaporated. Surface erosion is a typical sign of electric arc damage. Even short arcs can remove significant amounts of material from the electrodes. The temperature of the resulting electrical arc is very high (tens of thousands of degrees), causing the metal on the contact surfaces to melt, pool and migrate with the current, as well as to escape into the air as fine particulate matter.[1]
Damage
A short circuit fault current can, within milliseconds, be thousands of times larger than the normal operating current of the system.[2] Damage from short circuits can be reduced or prevented by employing fuses, circuit breakers, or other overload protection, which disconnect the power in reaction to excessive current. Overload protection must be chosen according to the current rating of the circuit. Circuits for large home appliances require protective devices set or rated for higher currents than lighting circuits. Wire gauges specified in building and electrical codes are chosen to ensure safe operation in conjunction with the overload protection. An overcurrent protection device must be rated to safely interrupt the maximum prospective short-circuit current.
In an improper installation, the overcurrent from a short circuit may cause ohmic heating of the circuit parts with poor conductivity (faulty joints in wiring, faulty contacts in power sockets, or even the site of the short circuit itself). Such overheating is a common cause of fires. An electric arc, if it forms during the short circuit, produces high amount of heat and can cause ignition of combustible substances as well.
In industrial and utility distribution systems, dynamic forces generated by high short-circuit currents cause conductors to spread apart. Busbars, cables, and apparatus can be damaged by the forces generated in a short circuit.
Related concepts
In electronics, the ideal model (infinite gain) of an operational amplifier is said to produce a virtual short circuit between its input terminals because no matter what the output voltage is, the difference of potential between its input terminals is zero. If one of the input terminals is connected to the ground, then the other one is said to provide a virtual ground because its potential is (ideally) identical to that of the ground.[3][4] An ideal operational amplifier also has infinite input impedance, so unlike a real short circuit, no current flows between the terminals of the virtual short.[5]
^"Lab Note #105 Contact Life - Unsuppressed vs. Suppressed Arcing". Arc Suppression Technologies. April 2011. from the original on September 30, 2018. Retrieved February 5, 2012.
^Bhatia, A. "Introduction to Short Circuit Analysis" (PDF). PDHonline. sec. What causes a short circuit?. (PDF) from the original on 3 July 2019. Retrieved 3 July 2019.
Bhatia, A. "Introduction to Short Circuit Analysis". PDHonline (Synopsis).
^Basic Electronics. I. K. International Pvt Ltd. March 2011. pp. 184–. GGKEY:9NLKFQ9D0F2. from the original on 2 May 2013. Retrieved 20 April 2011.
^Robert Spence (5 September 2008). Introductory Circuits. John Wiley and Sons. pp. 99–. ISBN978-0-470-77971-2. from the original on 2 May 2013. Retrieved 20 April 2011.
^U.A.Bakshi; A.P.Godse (1 January 2010). Linear Integrated Circuits. Technical Publications. pp. 4–. ISBN978-81-8431-773-2. Retrieved 20 April 2011.
External links
Look up short circuit in Wiktionary, the free dictionary.
Wikimedia Commons has media related to Short circuit.
Troubleshooting Strategy for US/Canadian Homes from The Circuit Detective
January 19, 2023
short, circuit, other, uses, disambiguation, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books. For other uses see Short circuit disambiguation This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Short circuit news newspapers books scholar JSTOR July 2019 Learn how and when to remove this template message 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 circuit The opposite of a short circuit is an open circuit which is an infinite resistance or very high impedance between two nodes Tree limbs cause a short circuit triggering an electrical arc during a storm Contents 1 Definition 2 Examples 3 Damage 4 Related concepts 5 See also 6 References 7 External linksDefinition EditA short circuit is an abnormal connection between two nodes of an electric circuit intended to be at different voltages This results in an electric current limited only by the Thevenin equivalent resistance of the rest of the network which can cause circuit damage overheating fire or explosion Although usually the result of a fault there are cases where short circuits are caused intentionally for example for the purpose of voltage sensing crowbar circuit protectors In circuit analysis a short circuit is defined as a connection between two nodes that forces them to be at the same voltage In an ideal short circuit this means there is no resistance and thus no voltage drop across the connection In real circuits the result is a connection with almost no resistance In such a case the current is limited only by the resistance of the rest of the circuit Examples EditA common type of short circuit occurs when the positive and negative terminals of a battery are connected with a low resistance conductor like a wire With a low resistance in the connection a high current will flow causing the delivery of a large amount of energy in a short period of time A high current flowing through a battery can cause a rapid increase of temperature potentially resulting in an explosion with the release of hydrogen gas and electrolyte an acid or a base which can burn tissue and cause blindness or even death Overloaded wires will also overheat causing damage to the wire s insulation or starting a fire In electrical devices unintentional short circuits are usually caused when a wire s insulation breaks down or when another conducting material is introduced allowing charge to flow along a different path than the one intended In mains circuits short circuits may occur between two phases between a phase and neutral or between a phase and earth ground Such short circuits are likely to result in a very high current and therefore quickly trigger an overcurrent protection device However it is possible for short circuits to arise between neutral and earth conductors and between two conductors of the same phase Such short circuits can be dangerous particularly as they may not immediately result in a large current and are therefore less likely to be detected Possible effects include unexpected energisation of a circuit presumed to be isolated To help reduce the negative effects of short circuits power distribution transformers are deliberately designed to have a certain amount of leakage reactance The leakage reactance usually about 5 to 10 of the full load impedance helps limit both the magnitude and rate of rise of the fault current A short circuit may lead to formation of an electric arc The arc a channel of hot ionized plasma is highly conductive and can persist even after significant amounts of original material from the conductors has evaporated Surface erosion is a typical sign of electric arc damage Even short arcs can remove significant amounts of material from the electrodes The temperature of the resulting electrical arc is very high tens of thousands of degrees causing the metal on the contact surfaces to melt pool and migrate with the current as well as to escape into the air as fine particulate matter 1 Damage EditA short circuit fault current can within milliseconds be thousands of times larger than the normal operating current of the system 2 Damage from short circuits can be reduced or prevented by employing fuses circuit breakers or other overload protection which disconnect the power in reaction to excessive current Overload protection must be chosen according to the current rating of the circuit Circuits for large home appliances require protective devices set or rated for higher currents than lighting circuits Wire gauges specified in building and electrical codes are chosen to ensure safe operation in conjunction with the overload protection An overcurrent protection device must be rated to safely interrupt the maximum prospective short circuit current In an improper installation the overcurrent from a short circuit may cause ohmic heating of the circuit parts with poor conductivity faulty joints in wiring faulty contacts in power sockets or even the site of the short circuit itself Such overheating is a common cause of fires An electric arc if it forms during the short circuit produces high amount of heat and can cause ignition of combustible substances as well In industrial and utility distribution systems dynamic forces generated by high short circuit currents cause conductors to spread apart Busbars cables and apparatus can be damaged by the forces generated in a short circuit Related concepts EditIn electronics the ideal model infinite gain of an operational amplifier is said to produce a virtual short circuit between its input terminals because no matter what the output voltage is the difference of potential between its input terminals is zero If one of the input terminals is connected to the ground then the other one is said to provide a virtual ground because its potential is ideally identical to that of the ground 3 4 An ideal operational amplifier also has infinite input impedance so unlike a real short circuit no current flows between the terminals of the virtual short 5 See also Edit Electronics portalAnnealing by short circuit Breaking capacity Conditional short circuit current Short circuit test Other electrical faults Ground fault Ohm s law Overcurrent electrical overloadReferences Edit Lab Note 105 Contact Life Unsuppressed vs Suppressed Arcing Arc Suppression Technologies April 2011 Archived from the original on September 30 2018 Retrieved February 5 2012 Bhatia A Introduction to Short Circuit Analysis PDF PDHonline sec What causes a short circuit Archived PDF from the original on 3 July 2019 Retrieved 3 July 2019 Bhatia A Introduction to Short Circuit Analysis PDHonline Synopsis Basic Electronics I K International Pvt Ltd March 2011 pp 184 GGKEY 9NLKFQ9D0F2 Archived from the original on 2 May 2013 Retrieved 20 April 2011 Robert Spence 5 September 2008 Introductory Circuits John Wiley and Sons pp 99 ISBN 978 0 470 77971 2 Archived from the original on 2 May 2013 Retrieved 20 April 2011 U A Bakshi A P Godse 1 January 2010 Linear Integrated Circuits Technical Publications pp 4 ISBN 978 81 8431 773 2 Retrieved 20 April 2011 External links Edit Look up short circuit in Wiktionary the free dictionary Wikimedia Commons has media related to Short circuit Troubleshooting Strategy for US Canadian Homes from The Circuit Detective Retrieved from https en wikipedia org w index php title Short circuit amp oldid 1133667289, wikipedia, wiki, book, books, library,
