View source for Selectivity (circuit breakers)

'''Selectivity''', also known as '''circuit breaker discrimination''', is the coordination of [[Circuit breaker|overcurrent protection devices]] so that a [[Electrical fault|fault]] in the installation is cleared by the protection device located immediately upstream of the fault. The purpose of selectivity is to minimize the impact of a failure on the network. Faults in an installation are, for example, overload and [[short circuit]].<ref>{{cite web|url=https://download.schneider-electric.com/files?p_Doc_Ref=LVPED318033EN|title=Selectivity, Cascading and Coordination Guide|author=|date=2021|publisher=[[Schneider Electric]]|page=A-2|language=en|format=pdf|access-date=18 September 2021|url-status=live|archive-url=https://web.archive.org/web/20210917145627/https://download.schneider-electric.com/files?p_Doc_Ref=LVPED318033EN|archive-date=17 September 2021}}</ref><ref name=NEC100Definition>{{Cite book | author=National Fire Protection Association | title= NFPA 70 National Electrical Code | access-date=October 9, 2023 | year=2017 | publisher=NFPA | location=1 Batterymarch Park, Quincy, Massachusetts 02169 |url=https://archive.org/details/gov.law.nfpa.nec.2017/gov.law.nfpa.nec.2017/page/n38/mode/1up | chapter=Article 100 Definitions | quote=Coordination, selective (selective coordination): localization of an overcurrent condition to restrict outages to the circuit or equipment affected, accomplished by the selection and installation of overcurrent protective devices and their ratings or settings for the full range of available overcurrents, from overload to the maxiumum available fault current, and for the full range of overcurrent protective device opening times associated with those overcurrents.}}</ref>

There are four ways in which selectivity is achieved:<ref>{{cite web|url=https://eduscol.education.fr/sti/sites/eduscol.education.fr.sti/files/ressources/techniques/3363/3363-ect201.pdf|title=Discrimination with LV power circuit-breakers|author=Jean-Pierre Nereau|date=April 2001|publisher=[[Schneider Electric]]|page=6|language=en|access-date=18 September 2021|url-status=live|archive-url=https://web.archive.org/web/20210917145624/https://eduscol.education.fr/sti/sites/eduscol.education.fr.sti/files/ressources/techniques/3363/3363-ect201.pdf|archive-date=17 September 2021}}</ref>
* Current selectivity: different [[Breaking capacity|breaking capacities]]
* Time selectivity: time delay before tripping of a breaker
* Energy based selectivity: analysis of the current waves
* Zone selective interlocking: communication between the breakers, forwarding a time delay instruction

==References==
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[[Category:Electrical engineering]]
[[Category:Electrical safety]]