All Topics  
Maximum prospective short circuit current

 

 
   Email Print
   Bookmark   Link
 

 

Maximum prospective short circuit current
 
 
  Topics Maximum prospective short circuit current Topic Home

The prospective short circuit current (PSCC) is the highest electric current
Electric current

Electric current is the flow of electric charge. The electric charge may be either electrons or ions.The International System of Units unit of electric current intensity is the ampere....
 which can exist in a particular electrical system under short circuit
Short circuit

A short circuit in an electrical circuit that allows a Electric current along a different path from the one intended.The electrical opposite of a short circuit is an "open circuit", which is an infinite resistance between two nodes....
 conditions. It is determined by the voltage
Voltage

Electrical tension is the potential difference between two points of an electrical or electronic circuit, expressed in volts. It is the measurement of the potential for an electric field to cause an electric current in an electrical conductor....
 and impedance
Electrical impedance

Electrical impedance, or simply impedance, describes a measure of opposition to a sinusoidal alternating current . Electrical impedance extends the concept of Electrical resistance to AC circuits, describing not only the relative amplitudes of the voltage and Electric current, but also the relative Phase ....
 of the supply system. It is of the order of a few thousand ampere
Ampere

The ampere is the International System of Units unit of electric current. The ampere, in practice often shortened to amp, is an SI base unit, and is named after Andr?-Marie Amp?re, one of the main discoverers of electromagnetism....
s for a standard domestic mains
Mains electricity

Mains is the general-purpose alternating current electric power supply. The term is not often used in the United States and Canada. In the US, mains power is referred to by a variety of formal and informal names, including household power, household electricity, domestic power, wall power, line power, AC p...
 electrical installation, but may be as low as a few milliamperes in a SELV (Safety Extra Low Voltage or, occasionally, Separated Extra Low Voltage) system or as high as hundreds of thousands of amps in large industrial power systems.

Importance
It is of particular interest when designing an electrical installation because fuses
Fuse (electrical)

In electronics and electrical engineering a fuse is a type of overcurrent protection device. Its essential component is a metal wire or strip that melts when too much current flows, which breaks the electrical network in which it is connected, thus protecting the circuit's other components from damage due to excessive current....
 and circuit breaker
Circuit breaker

A circuit breaker is an automatically-operated Electricity switch designed to protect an Electrical network from damage caused by Overcurrent or short circuit....
s must be capable of safely breaking the current in the event of a short circuit.






Discussion
Ask a question about 'Maximum prospective short circuit current'
Start a new discussion about 'Maximum prospective short circuit current'
Answer questions from other users
Full Discussion Forum



Encyclopedia


The prospective short circuit current (PSCC) is the highest electric current
Electric current

Electric current is the flow of electric charge. The electric charge may be either electrons or ions.The International System of Units unit of electric current intensity is the ampere....
 which can exist in a particular electrical system under short circuit
Short circuit

A short circuit in an electrical circuit that allows a Electric current along a different path from the one intended.The electrical opposite of a short circuit is an "open circuit", which is an infinite resistance between two nodes....
 conditions. It is determined by the voltage
Voltage

Electrical tension is the potential difference between two points of an electrical or electronic circuit, expressed in volts. It is the measurement of the potential for an electric field to cause an electric current in an electrical conductor....
 and impedance
Electrical impedance

Electrical impedance, or simply impedance, describes a measure of opposition to a sinusoidal alternating current . Electrical impedance extends the concept of Electrical resistance to AC circuits, describing not only the relative amplitudes of the voltage and Electric current, but also the relative Phase ....
 of the supply system. It is of the order of a few thousand ampere
Ampere

The ampere is the International System of Units unit of electric current. The ampere, in practice often shortened to amp, is an SI base unit, and is named after Andr?-Marie Amp?re, one of the main discoverers of electromagnetism....
s for a standard domestic mains
Mains electricity

Mains is the general-purpose alternating current electric power supply. The term is not often used in the United States and Canada. In the US, mains power is referred to by a variety of formal and informal names, including household power, household electricity, domestic power, wall power, line power, AC p...
 electrical installation, but may be as low as a few milliamperes in a SELV (Safety Extra Low Voltage or, occasionally, Separated Extra Low Voltage) system or as high as hundreds of thousands of amps in large industrial power systems.

Importance


It is of particular interest when designing an electrical installation because fuses
Fuse (electrical)

In electronics and electrical engineering a fuse is a type of overcurrent protection device. Its essential component is a metal wire or strip that melts when too much current flows, which breaks the electrical network in which it is connected, thus protecting the circuit's other components from damage due to excessive current....
 and circuit breaker
Circuit breaker

A circuit breaker is an automatically-operated Electricity switch designed to protect an Electrical network from damage caused by Overcurrent or short circuit....
s must be capable of safely breaking the current in the event of a short circuit. When a large electric current is interrupted an arc
Electric arc

An electric arc is an electrical breakdown of a gas which produces an ongoing Plasma Electrostatic discharge, resulting from a current flowing through normally Electrical conductance media such as air....
 may form and if the breaking capacity
Breaking capacity

The breaking capacity gives the current that an electrical apparatus is able to interrupt without being destroyed or causing an electric arc with unacceptable duration....
 of a fuse or circuit breaker is exceeded then it may not be able to extinguish this arc meaning that the current will continue, possibly resulting in a fire
Fire

Fire is the oxidation of a combustion material releasing heat, light, and various Chemical reaction products such as carbon dioxide and water....
 or explosion
Explosion

An explosion is a sudden increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases....
.

In domestic power installations in all countries (230 V
Voltage

Electrical tension is the potential difference between two points of an electrical or electronic circuit, expressed in volts. It is the measurement of the potential for an electric field to cause an electric current in an electrical conductor....
 50 Hz for Europe, 120 V
Voltage

Electrical tension is the potential difference between two points of an electrical or electronic circuit, expressed in volts. It is the measurement of the potential for an electric field to cause an electric current in an electrical conductor....
 60 Hz for North America AC
Alternating current

In alternating current the movement of electric charge periodically reverses direction. An electric charge would for instance move forward, then backward, then forward, then backward, over and over again....
 single phase power) the short circuit current available on the electrical outlets needs to be taken into account when designing electrical power wiring. The short circuit current should not be too high or too low. The effect of too high short circuit current is discussed in the previous paragraph. The short circuit current should be of the order of around 200 A
Ampere

The ampere is the International System of Units unit of electric current. The ampere, in practice often shortened to amp, is an SI base unit, and is named after Andr?-Marie Amp?re, one of the main discoverers of electromagnetism....
 or higher for normal 10 A or 16 A outlet to guarantee that the normal wire protecting fuse or breaker will quickly disconnect the supply in case of short circuit. Quick disconnecting is needed, because in live-ground short circuit the grounding pin potential on the power outlet can rise compared to the local earth (concrete floor, water pipe etc.) during short circuit to a dangerous voltage, which needs to be shut down quickly for safety. If the short circuit current is lower than this figure, special precautions need to be taken to make sure that the system is safe; those usually include using a residual current device for extra protection.

The short circuit current available on the electrical outlets is often measured with a suitable instrument when examining electrical installations to make sure that the short circuit current is within reasonable limits. Having a high enough short circuit current on the outlet will also tell that the resistance from the electrical panel to the outlet is reasonably low, so there will not be too high voltage losses on the wires when outlets are loaded normally.

See also


  • Breaking capacity
    Breaking capacity

    The breaking capacity gives the current that an electrical apparatus is able to interrupt without being destroyed or causing an electric arc with unacceptable duration....