Talk:Arc-fault circuit interrupter

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Detection Method
I came to this article seeking information as to the method used to detect arcs. I found no information in this regard. LorenzoB (talk) 03:20, 29 August 2011 (UTC)

75.150.19.214 (talk) 01:33, 10 January 2012 (UTC)

(anonymous) I had the same issue. Doing some further research, several methods exist. One involves sensing the current and applying an "arc signature filter" (as an EE this is insanely vague but presumably fault arcs vs. normal arcs have a unique frequency domain spectrum). This document from one vendor (Eaton) has a block diagram:

http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/1037920105765.pdf

A NEMA document on the Eaton site has a frequently reproduced diagram with more information (if you zoom in - no one reproducing the diagram has figured this out yet!).

http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/ct_135970.pdf

Zoomed here

http://imgur.com/nxCAX

Apparently ground (serial) arcs are detected like ground faults (regular ground faults are triggered at 5-6 mA already with a GCFI). Parallel faults (line to neutral) are detected by "signature" and must exceed 75A (which is pretty high for a 20A/30A but this is a transient 75A while a conventional breaker detects a sustained 20A/30A).

This IEEE paper by an Eaton engineer shows current-voltage waveforms that are part of what the arc signature is detecting though it isn't very specific mathematically:

http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/ct_136020.pdf

Related to this is an interesting note in an Eaton FAQ: you can neutralize false positive trips caused by appliances by using a surge protector (which apparently filters out arc signature currents from reaching the breaker). Detection is a dicey proposition in other words.

http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/ct_206788.pdf

GE's, Schneider and Siemens information is essentially useless. I'm guessing Eaton invented the primary technologies and the others just license patents from Eaton.

One other method involves Spread Spectrum Time Domain Reflectometry (SSTDR). Fairly expensive (ICs for this run US$ 50 a piece) so probably not typically used for home use.
 * Patents somtimes are good resources for figuring out how something works. I wonder what the patent numbers are? I'd have to look at some arcing GCFIs...--Wtshymanski (talk) 14:57, 10 January 2012 (UTC)

How does it work
Why is not described in the article how such device works? — Preceding unsigned comment added by 91.46.185.127 (talk) 20:06, 3 February 2012 (UTC)


 * The article does not give specifics because the industry and manufacturers have not authoritaritively published detailed functionality or internals. The links in the section above are the best sources I have seen.  They hint that the current waveform is analyzed (by digital and/or analog electronics) with additional logic for a time factor to determine a valid trip condition.  The documents also hint that a dangerous arc can occur with as little as 0.25 amps, so strictly current based detection is not adequate.  Most AFCIs tolerate 75 to 85 amps inrush current, the condition that occurs for a few milliseconds when a motor or incandescent lamp is first turned on.  —EncMstr (talk) 21:34, 3 February 2012 (UTC)


 * and, both assigned to Eaton Corporation provide operational details and a few specifies. —EncMstr (talk) 09:55, 8 February 2012 (UTC)
 * Whoops. 204949 is a 19th century patent for musical instruments.  The other one seems relevant.  What was the first patent number supposed to be? --Wtshymanski (talk) 17:47, 8 February 2012 (UTC)
 * Hmmm, this link seems to have been intended, but it is a submission—not an actual patent. I have puzzled over it for a couple minutes, but I don't see a cross reference to a patent.  —EncMstr (talk) 18:02, 8 February 2012 (UTC)

If there is no published, open-source specification on how a AFCI is supposed to work, then how can a AFCI device be certified safe and effective to use? --71.10.155.250 (talk) 22:46, 26 November 2016 (UTC)
 * As well as I know, it is the high frequencies usually generated by arcs. That is, the same physics as spark gap radio transmitters. Gah4 (talk) 10:02, 20 March 2021 (UTC)
 * As well as I know, it is the high frequencies usually generated by arcs. That is, the same physics as spark gap radio transmitters. Gah4 (talk) 10:02, 20 March 2021 (UTC)

Playful circuit interrupter
1,000 deaths are caused each year from fires caused by playing with electricity. Play Circuit Interrupters (PCIs) interrupt a circuit when they detect the signature current patterns caused by children who are flipping the light switch on and off too fast. They will be required in the 2013 NEC.

PCIs article should be linked to AFCIs because they are basically the same idea, to make more money for device manufacturers. — Preceding unsigned comment added by 173.66.54.78 (talk) 15:17, 1 May 2012 (UTC)


 * Got a citation? Is there such an article?  Searches for playful circuit interrupter show nothing close.  —EncMstr (talk) 19:22, 1 May 2012 (UTC)


 * no citation for the fire death data as it is plain wrong. Just look at the NFPA stats: http://www.nfpa.org/assets/files/pdf/os.homes.pdf Looks like the contributor is trying to be humourous! Interestingly AFIs are designed to ignore inrush currents when coils (in GLS light bulbs and motors for example)are energised....and repeatedly switching lights on and off is not an accepted cause of fire. Can't find a citation for that other than 20 years in fire investigation — Preceding unsigned comment added by Lardyl (talk • contribs) 23:53, 19 February 2013 (UTC)


 * I have the 2014 edition of the NEC (NFPA-70) and there is nothing in the index about a "PCI" or "Playful Circuit Interrupter".--71.10.145.225 (talk) 20:43, 7 December 2014 (UTC)

Safety - but at what cost?
Just to note that AFCI and GFCI breakers are much more expensive than regular breakers. If I were to follow the NEC code (NFPA-70), over half the breakers in my 20 year old house would need to be replaced with AFCI's, which cost 5x more than conventional circuit breakers and might also be prone to false arc events. For my house, that would cost a minimum of $600 in materials alone. Section 210.12 of the 2014 NEC (regarding AFCI's) states: "All 120-volt, single-phase, 15- and 20-ampere branch circuits supplying outlets or devices installed in dwelling unit kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas, or similar rooms or areas shall be protected..."   Plus I don't get an insurance discount for upgrading to AFCI's, and AFCI dual-breakers at 15- and 20-amp are not available to match my electrical box, so I would need to add a sub-panel too. At one time, NFPA was pushing to have new houses have sprinkler systems installed throughout a new house too. Mandates like use of AFCI's (and also TR Tamper Resistant and WR Weather Resistant receptacles) don't offer much opportunity for risk management. To be compliant, the price must be paid, and I am bothered that the price is high and the benefits seem low to me, considering that I already have circuit breaker protection of all branch circuits, and GFCI's at all required locations; as well has smoke detectors, CO detectors, and three ABC fire extinguishers. There is plenty of opportunity to debate the merits of AFCI's, but the mandate is IMO a hardship. I also suspect there may be cheaper techniques for preventing Arc Faults or their effects. 71.10.145.225 (talk) 15:48, 15 November 2014 (UTC)
 * A referenced summary of authorities' discussions of the cost/benefit and justification for including AFCIs in current electrical codes would be a useful contribution to the article. --Wtshymanski (talk) 21:15, 19 November 2014 (UTC)


 * Existing installations are not generally required to be refitted for compliance with later electrical code unless you're remodeling, modifying branch circuits, or changing the certificate of occupancy somehow (e.g., converting to a residential day-care). Under NFPA 70 (2014) you do not have to replace any circuit breakers; you can add an AFCI at the first outlet on each branch requiring protection, provided it is within the distance limit (e.g., 70 ft for 12 AWG), or is wired using a metallic wiring method (metal conduit or armored cables and metal junction boxes). 210.12(A)(5). Lupinelawyer (talk) 01:58, 14 August 2016 (UTC)

Questions on AFCI behaviour under non-ideal power source conditions
Not knowing exactly how they work (since that information is lacking), I'd like to know how AFCI's would behave if I switched power over from city main to generator power after a power outage (and also back). Or when there is a thunderstorm in the area. Is "spectral purity" from a generator (or city power) required for proper AFCI operation? I'd hate to fire up my generator only to find all my household AFCI breakers keep false-tripping on it. If this cannot be answered, then I would question whether AFCI technology is sufficiently reliable/mature for mainstream use.--71.10.145.225 (talk) 23:36, 19 November 2014 (UTC)


 * I researched it a year ago or more but have not gotten around to adding it to the article. I found that arcs have a repeating pulse pattern in the 100 kHz to 2 MHz range and this is the key characteristic that most—if not all—AFCIs are triggering upon.  Generators and thunderstorms do not have those characteristics, so an AFCI would be safe with any combination of common power sources, even when struck by lightning.  —EncMstr (talk) 05:54, 20 November 2014 (UTC)

Questions on AFCI behaviour under non-ideal power load conditions
And what of loads which are subject to drawing occasional transient current spikes ? For example an high-power audio amplifier fed from say an AM radio tuned to a weak station riddled with static interference. Could such loads cause nuisance tripping when AFCI's are utilized ? 2.127.209.195 (talk) 21:32, 24 May 2015 (UTC)


 * This is unlikely since your radio probably has a AC-DC conversion, and whatever noise on the AM station is unlikely to propagate backwards onto the power line due to power supply filtering.  From the standpoint of a "load", the AFCI sees an abstract device with a (likely regulated) DC power supply, not what is being received by the radio.   Its the same with digital noise in your alarm clock or cell phone or any other device operating from DC conversion - noise gets filtered by the power supply before it shows on on the AFCI line.  --2600:6C48:7006:200:D84D:5A80:173:901D (talk) 23:45, 27 May 2017 (UTC)

AFCI standby power information requested
Does anyone have any information on how much standby power a AFCI circuit breaker requires to maintain operation? I am struggling to find this information. There could be an operational cost having an AFCI draw standy power 24/7 even under no-load conditions. --71.10.145.225 (talk) 23:17, 19 November 2014 (UTC)

Colocar la información sobre el AFD detector de arcos en español
Mi nonbre es Ariel Dyfort "trabajo en Siemens Argentina, y me gustaría colocar la información del detector de arco en español. ¿Hay alguien en la comunidad de Wikipedia que está en desacuerdo con ello? — Preceding unsigned comment added by 194.138.184.221 (talk) 17:15, 10 September 2013 (UTC)
 * El lugar adecuado para preguntar es en la Wikipedia en español. [The proper place to ask is on the Spanish Wikipedia.]  —EncMstr (talk) 21:15, 10 September 2013 (UTC)


 * How do I translate this category/question?  --71.10.145.225 (talk) 20:49, 7 December 2014 (UTC)


 * If you are asking what the question/comment means in English, it from someone who says he works at Siemens in Argentina and wonders if a Spanish version of this article would be okay to write. —EncMstr (talk) 21:27, 7 December 2014 (UTC)

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AFCIs warm?
I took infrared pictures of my panel and found that the AFCIs were warm. None of the other breakers were, and no special loads are on those circuits, certainly not on both of them. Curious if that is inherent to the design and how much energy is wasted by whatever heats them up. — Preceding unsigned comment added by Tenbergen (talk • contribs) 23:07, 12 January 2017 (UTC)

2600:6C48:7006:200:D84D:5A80:173:901D (talk) 23:52, 27 May 2017 (UTC)
 * this "thermal image" looks suspicious.  Note the sharp corner and edge transitions between hot and cold regions.   Plus it would be better to take such an image with the cover removed.--

It’s really amazing how much people use talk pages for electrical topics on Wikipedia to post DIY questions. I don’t think that’s what the tag pages for. Is there a talk page for the talk page where we can talk about these types of problems with the DIYers on the talk pages?

Power fault circuit interrupter
There are several references in this article to Power Fault Circuit Interrupters, but I cannot find any further information about them online. All I found are brief mentions in sites advertising proprietary receptacle products. I am marking these references as "citation needed" for now, but I think it would be good if someone with more knowledge in this area can either find citations or remove the references altogether. 75.71.97.154 (talk) 03:30, 19 November 2017 (UTC)

Overspecific Limitations
There are a few claims under the limitations heading which seem pretty irrelevant for example:

"Also, AFCIs provide no specific protection against glowing connections also known as a High Resistance Connection, excess current, high line voltages or low line voltages. AFCI circuit breakers include a standard inverse-time circuit breaker. Glowing connections occur when relatively high current exists in a relatively large resistance object. Heat comes from power dissipation. This energy, when dissipated in a small junction area, can generate temperatures above 1000 °C (1800 °F) and can ignite most flammable materials."

Might as well say a bullet proof vest does not protect against drowning. Shall we keep this text or clean it up?

Bostwickenator (talk) 14:36, 5 January 2018 (UTC)

National Electrical Code cleanup needed
Right now we have a nice summary of the US NEC requirements in 1999 and then new paragraphs for each year stating only the differences of how the Code changed from the previous revision. It is interesting as a history, but not so useful for people wanting to understand the present situation. It would be good if somebody merged them into a new first paragraph that summarizes the current state of the Electrical Code. Ben (talk) 04:12, 10 March 2021 (UTC)


 * NB: the version of the current electrical code adopted (required) varies by state, so I favor keeping the current presentation. Gorbag42 (talk) 01:42, 27 December 2023 (UTC)

arc lamps
There is a section on causes of false positive triggering. I do wonder, though, about arc lamps, such as fluorescent lamps or HID lamps, which obviously also have an arc. Do they avoid them, and if so, how? Gah4 (talk) 10:06, 20 March 2021 (UTC)