Editing Residual-current device (section)

{{Short description|Electrical safety device used in household wiring}}
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{{Infobox electronic component
 | component         = Residual-current device
 | photo             = FISkizze.svg
 | caption           = '''Basic diagram'''<br />1: Electromagnet<br/>2: Current transformer secondary winding<br/>3: Transformer core<br/>4: Test push-button<br/>L: {{Not a typo|Line}} conductor<br/>N: Neutral conductor
}}
{{Electrical Wiring Sidebar}}

A '''residual-current device''' ('''RCD'''), '''residual-current circuit breaker''' ('''RCCB''') or '''ground fault circuit interrupter''' ('''GFCI'''){{efn|''RCD'' and ''RCCB'' are international terms used in standards produced by the [[International_Electrotechnical_Commission|IEC]], upon which many national standards are based, such as that of the [[United Kingdom]] and [[Europe]]. In the [[United States]] and [[Canada]] ''GFCI'', ''ground fault interrupter'' (''GFI''), ''appliance leakage current interrupter'' (''ALCI''), and ''leakage current detection interrupter'' (''LCDI'') are used.|name=othernames}} is an electrical safety device, more specifically a form of [[Earth-leakage circuit breaker]], that interrupts an [[Electrical Circuit|electrical circuit]] when the current passing through {{Not a typo|line}} and neutral conductors of a circuit is not equal (the term ''residual'' relating to the [[remainder|imbalance]]), therefore indicating [[Leakage (electronics)|current leaking]] to [[Ground (electricity)|ground]], or to an unintended path that bypasses the protective device. The device's purpose is to reduce the severity of injury caused by an [[electric shock]].<ref>{{Cite web|url=https://www.osha.gov/SLTC/etools/construction/electrical_incidents/gfci.html|title=Construction eTool {{!}} Electrical Incidents - Ground-fault Circuit Interrupters (GFCI) {{!}} Occupational Safety and Health Administration|website=www.osha.gov|access-date=2019-04-05}}</ref> This type of circuit interrupter cannot protect a person who touches both circuit conductors at the same time, since it then cannot distinguish normal current from that passing through a person.<ref> Philip Coombs Knapp, ''Accidents from the Electric Current: A Contribution to the Study of the Action of Current: of High Potential Upon the Human Organism.'' Damrell & Upham, 1890, page 13 </ref>

A [[#RCBO2|'''residual-current circuit breaker with integrated overcurrent protection''' ('''RCBO''')]] combines RCD protection with additional [[overcurrent protection]] into the same device.

These devices are designed to quickly interrupt the protected circuit when it detects that the [[electric current]] is unbalanced between the supply and return conductors of the circuit. Any difference between the currents in these conductors indicates [[leakage current]], which presents a shock hazard. Alternating 60 Hz current above 20&nbsp;[[Ampere|mA]] (0.020 amperes) through the human body is potentially sufficient to cause [[cardiac arrest]] or serious harm if it persists for more than a small fraction of a second. RCDs are designed to disconnect the conducting wires ("trip") quickly enough to potentially prevent serious injury to humans, and to prevent damage to electrical devices.

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File:Residual current device 2pole.jpg|A two-pole, or double-pole, residual-current device. The test button and connect/disconnect switch are colored blue. A fault will trigger the switch to its off (down) position, which in this device would disconnect both conductors.
File:IEC TS 60479-1 electric shock graph.svg|Log–log graph of the effect of alternating current ''I'' of duration ''T'' passing from left hand to feet as defined in [[International Electrotechnical Commission|IEC]] 60479-1<ref>Weineng Wang, Zhiqiang Wang, Xiao Peng, [http://papersub.ivypub.org/Global/DownloadService.aspx?PARAMS=Sm91cm5hbElEXjM3OF5JRF4xNDAzOQ_0_0 ''Effects of the Earth Current Frequency and Distortion on Residual Current Devices''], Scientific Journal of Control Engineering, Dec 2013, Vol. 3, Issue 6, p. 417–422.</ref>
File:Residential GFCI receptacle.jpg|Typical GFCI receptacle found in North America
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