Editing Arc-fault circuit interrupter (section)

{{short description|Circuit breaker that protects against intermittent faults associated with arcing}}
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[[File:Arc Fault Circuit Interrupter.jpg|thumbnail|upright=1.2|This AFCI (the circuit breaker with the yellow label) is an older generation AFCI circuit breaker. The current (as of 2013) devices are referred to as "combination type."]]
An '''arc-fault circuit interrupter''' ('''AFCI''') or '''arc-fault detection device''' ('''AFDD''')<ref>{{cite web |title=Do you know an Arc Fault Detection Device (AFDD) can prevent from an electrical fire? |url=https://blog.schneider-electric.com/power-management-metering-monitoring-power-quality/2013/07/03/do-you-know-an-arc-fault-detection-device-afdd-can-prevent-from-an-electrical-fire/ |publisher=Schneider Electric}}</ref> is a [[circuit breaker]] that breaks the circuit when it detects the [[electric arcs]] that are a signature of loose connections in home wiring. Loose connections, which can develop over time, can sometimes become hot enough to ignite house fires. An AFCI selectively distinguishes between a harmless arc (incidental to normal operation of switches, plugs, and brushed motors), and a potentially dangerous arc (that can occur, for example, in a lamp cord which has a broken conductor).

In [[Canada]] and the [[United States]], AFCI breakers have been required by the electrical codes for circuits feeding [[electrical outlet]]s in residential bedrooms since the beginning of the 21st century; the US ''[[National Electrical Code]]'' has required them to protect most residential outlets since 2014,<ref>2014 NEC(210.12)</ref> and the ''[[Canadian Electrical Code]]'' has since 2015.<ref>{{cite book |title=C22.1-15 – Canadian Electrical Code, Part I: Safety Standard for Electrical Installations |date=2015 |publisher=Canadian Standards Association |isbn=978-1-77139-718-6 |edition=23rd |page=Rules 24–724(f) & (g) |language=en |no-pp=y}}</ref>

In regions using 230&nbsp;V, the combination of higher voltage and lower load currents lead to different conditions being required to initiate an arc fault that does not either burn clear or weld to a short circuit after a short time, and there are different arc characteristics once struck. Because of this, in Western Europe (where in many countries a domestic supply may be 400V 3 phase) and the UK (where domestically a single phase 230V supply is common), adoption is slower, and their use is optional, only being mandated in specified high risk locations. The Australian and New Zealand regulations – Wiring Rules (AS NZS 3000:2018) do not require installation of AFDDs in Australia. However, in New Zealand all final sub-circuits with ratings up to 20&nbsp;A will require protection by an AFDD if they supply locations with significant fire risk, locations containing irreplaceable items, certain historic buildings, and socket-outlets in school sleeping accommodation.<ref name=ASNZS3000>{{Cite web|url=https://www.gses.com.au/wiringrulesasnzs3000/|title=Wiring Rules AS NZS 3000:2018 – Key Updates to the Standard and What They Mean for Installers|date=24 July 2018}}</ref> Most sockets in these countries are on circuits rated at 20 A or less.

In the US, arc faults are said to be one of the leading causes for residential electrical fires.<ref>{{cite journal|title=New Technology for Preventing Residential Electrical Fires: Arc-Fault Circuit Interrupters (AFCIs)|journal=Fire Technology|volume=36|issue=3|publisher=Kluwer Academic Publishers|date=Aug 2000|pages=145–162|url=http://www.cpsc.gov//PageFiles/108737/AFCIFireTechnology.pdf|doi=10.1023/A:1015410726786|first1=Douglas A.|last1=Lee|first2=Andrew M.|last2=Trotta|first3=William H.|last3=King|s2cid=108941129|issn=0015-2684|access-date=Feb 26, 2013}}</ref> Each year in the United States, over 40,000 fires are attributed to home electrical wiring. These fires result in over 350 deaths and over 1,400 injuries each year.<ref>Ault, Singh, and Smith, "1996 Residential Fire Loss Estimates", October 1998, U.S. Consumer Product Safety Commission, Directorate for Epidemiology and Health Sciences.</ref>

Conventional circuit breakers respond only to [[overcurrent|overloads]] and [[short circuit]]s, so they do not protect against arcing conditions that produce erratic, and often reduced current. AFCIs are devices designed to protect against fires caused by arcing faults in the home electrical wiring. The AFCI circuitry continuously monitors the current and discriminates between normal and unwanted arcing conditions. Once detected, the AFCI opens its internal contacts, thus de-energizing the circuit and reducing the potential for a fire to occur.<ref>"Arc Fault Circuit Interrupter (AFCI)FACT SHEET" accessed from http://www.cpsc.gov/CPSCPUB/PUBS/afcifac8.PDF. {{Webarchive|url=https://web.archive.org/web/20100720124540/http://www.cpsc.gov/cpscpub/pubs/afcifac8.pdf|date=2010-07-20}}, July 22, 2010.</ref>