Talk:Residual-current device

GFI/GFCI

From the article:

The terms ground fault circuit interrupter (GFCI) or ground fault interrupter (GFI) are used in the United States and Canada, but these terms are not, strictly speaking, correct (or at least complete), because a RCD will trip if current leaks anywhere, not just to ground.

In NEC terminology, power flows between the "ungrounded conductor" and the "grounded conductor" (with the load in the middle) . If more power is flowing through the ungrounded conductor then the grounded conductor (unbalanced), then there is a ground fault (a failure to ground properly), and so the circuit should be interrupted. Looking at it this way, the terms GFCI and GFI make more sense, and is how I always assumed they came about.

Notes: The "ungrounded conductor" is colloquially called "hot" or "line". The "grounded conductor" is also called the "identified conductor", and is colloquially (and sometimes incorrectly) called "neutral". Note that none of these are the "equipment grounding conductor", which is colloquially called "safety ground" or just "ground". Yes, NEC terminology is confusing.

--DragonHawk 15:23, 19 Jun 2005 (UTC)

But ground isn't the only place the errant current can go; it might return on the other hot leg of a split-phase system, the neutral leg of another branch circuit, or it might even leak unto a de-energized part of another circuit (the switched leg going to a lamp or a circuit de-energized by opening its breaker). I think it was this thought that provoked the original author to speak of "ground fault" being something of a misnomer. And it's certainly true that the devices sense "balanced current" and not a "ground fault" in particular. Compare this with certain ungrounded systems (for example, railway traction motor circuits) where there ctually are devices that are purely sensitive to ground faults; any grounding of the ungrounded system trips the detectors and removes power. Such devices would be properly called GFCIs.

Atlant 11:55, 20 Jun 2005 (UTC)

Yes, and also in many renewable energy systems, some of them are wired up in a balanced way with neither of the two wires connected to ground, in which case, of course, there must be a breaker on both sides. In this case there is no ground, and no concept of ground fault. Thus what's really being measured and detected is a balance fault, i.e. basically what would be a violation of Kirchoff's current law, were it not for the unknown existence of some other leakage current somewhere else (not necessarily to or from ground). Also the concept of a balance fault nicely generalizes to three phase, where, for example, a three-phase BFI could trip if there was any imbalance of total current (i.e. if the total current didn't sum to exactly zero). Glogger 23:02, 30 December 2005 (UTC)

I have (re-?) inserted a brief explanation that GFCI is the usual name in the U.S. and Canada, which it certainly is, regardless of arguments as to whether the term is strictly defensible. On a related note, is "Balance Fault Interrupter" used anywhere? If it does appear in documentation or industry literature, a cite is in order; if it's new coinage proposed by a Wikipedia contributor, it really doesn't belong. Sharkford 19:27, 1 February 2006 (UTC)

Strictly speaking, a GFCI is different from a RCD in that a GFCI will trip in the presence of a neutral-earth fault (even though there is no voltage difference). It does this by having a second coil around the supply conductors (as well as the sensor coil). This provides a positive feedback loop when the neutral-earth circuit is made (ground-fault) and the GFCI trips. A RCD will not do this.--210.55.171.62 23:14, 17 October 2006 (UTC)

miswirings

From the article:

Manufacturers are now designing such devices that will disconnect their circuit, even if they don't dectect electrical leaking, if they are wired improperly.

Really? How? Under all possible miswirings, or only some? -- The Anome 08:50, 26 May 2004 (UTC)

I don't understand this either. It's just a guess on my part, but since the most common wiring error is reversal of line and load connections on receptacle devices, the manufacturers may be doing something to detect that particular condition and trip. UninvitedCompany 14:44, 26 May 2004 (UTC)

Some types of RCD incorporate an additional device which trips if the voltage between the earth (ground) and neutral conductors rises above a certain potential. This would also detect a miswiring where the live (hot) and neutral conductors were reversed. --Ali@gwc.org.uk 13:20, 17 Jul 2004 (UTC)

How do RCDs actually trip?

Using the example of the illustrated "outlet-style" RCD, the description used to speak about the solenoid being continuously energized and that providing the latch that kept the RCD "reset". This description is clearly inconsistent with at least US-style RCDs as it would imply that a power failure would also lead to the dropping-out of all of the RCD solenoids, their subsequent tripping, and the need to manually reset all the RCDs after power was restored. This ain't the way it works in practice.

I conclude from this that the mechanism operates in the opposite fashion: The latch is mechanically held and the RCD activates the solenoid when it wants to "trip" the RCD by unlatching the latch. I've changed the text to reflect this view of the world. But if Europe has "outlet-style" RCDS and they operate as originally described, please feel free to extend the text to explain this.

Meanwhile, I guess I'll take an American RCD apart this week-end and check for certain. :-)

Atlant 19:27, 3 Jun 2005 (UTC)

In Europe you can get both passive rcds (which don't trip out on power failure) and active rcds (which do). Generally most rcds in consumer units etc are the passive type but the active type is considered advisible for supplying equipment which can pose a danger on unexpected re-energistation. Plugwash 20:57, 3 Jun 2005 (UTC)

Thanks! Atlant 23:22, 3 Jun 2005 (UTC)

What is the "residual" in RCD?

I accept the points of those who say that ELCB is not technically accurate but at least it is descriptive. I haven't been able to figure out what "residual" means. Any ideas? Harmonitron

THe residual current is the difference between the phase current and the neutral current. There shouldnt be any diff if you have no leakage to earth. But if there is a leakage it means some normally earthed part is live, and this will be sensed by the balanced coil and trip out.--Light current 23:51, 23 April 2006 (UTC)

RCD's and MEN connections

What are the implications of using RCD protection where MEN connections are present?

What are MEN conns? Is it the same as PME Protective_multiple_earthing (protective multiple earthing in UK?)--Light current 08:36, 5 May 2006 (UTC)

Assuming you mean a neutral thats tied to real earth at multiple points and/or used as a protective conductor as well as a neutral there are two reasons why a RCD shouldn't be used in such a core.

1. Paralell paths bypassing the RCD will cause it to trip when it shouldn't
2. Isolating a combined neutral and earth core is a BAD idea.

However its perfectly fine to feed a RCD from such a system provided neutral and earth remain seperate after the RCD and the only path from the outgoing neutral to the transformer neutral is to go through the RCD. Plugwash 09:09, 5 May 2006 (UTC)

There is a subtle issue with PME and this type of breaker. If you have a neutral to earth fault, you get a low impedance circuit through the PME connection and the fault, so you have a short-circuit around one of the sensing coils. The effect of this is to desensitize the breaker, esp. if the neutral to earth fault is close to the breaker. pjb 07:12, 25 January 2010 (UTC) —Preceding unsigned comment added by 90.203.67.235 (talk)

alternative names for the device

at this forum thread lots of different names for RCDs in English have been listed. TERdON 22:36, 8 May 2006 (UTC)

RCDs in Australia

The article doesn't seem to mention anything about Australia's regulations, so the short version:

RCDs must trip at no more that 30mA within 20ms (this is because anything over 35mA is likely to kill a person if it goes through their heart). RCDs must be installed for any new circuits added to a domestic situation (this includes lighting circuits). The only exception to this is where it would be deemed to add greater risk (such as emergency lighting or smoke alarms.) Also, if there is only one appliance wired into a circuit, it does not require an RCD (eg - an oven). It is common practice for electricians to run a dedicated circuit for older fridges that do not pose a risk. Also, RCD's are usually refered to as Safety Switches by the general public.

Hope that added to the info. Blaab 10:34, 28 September 2006 (UTC)

I have difficulty believing this. I live in Victoria, and we had three new circuits installed in September 2007, a year after the previous article, and none of them had RCDs on them. Two were for air conditioners, and one was a dedicated 20 A circuit for a dish washer. My understanding is that RCDs are only required where human contact with the circuit is possible. Groogle (talk) 06:05, 23 December 2008 (UTC)

Did you not note that "Blaab" wrote "if there is only one appliance wired into a circuit, it does not require an RCD (eg - an oven)"? In your case, you had "three new circuits installed" for (two) air conditioners and one dishwasher. This IS a case of each appliance being wired into its own separate circuit. It is almost certain that the air conditioners would have been directly "wired" into the (16 A) circuits concerned (without a socket outlet) and the dish-washer would have been connected to its own dedicated 20 A circuit, with which a socket outlet may or may not have been involved. (I am surprised to hear of a dish-washer which required 20 A at 230 V. This could be over 4,500 Watts, when most domestic dish-washers would draw less than 2,000 Watts. Hence, I presume that yours is an an industrial or restaurant situation.)Fredquint (talk) 15:19, 13 May 2014 (UTC)

Rename article to more commonly used term Ground fault circuit interrupter

I wonder if more of these devices are in use in the UK or in the US? What are they called in other English speaking countries? We should title the article with whatever is the more common term. Checking Google, I see for "ground fault interrupter" 96,100 hits, for "ground fault circuit interrupter" 167,000 hits, and for "Residual-current device" only 67,300 which reduces to 65,000 when Wikipedia and its mirror sites are removed. I propose renaming the article to "Ground fault circuit interrupter" unless there is a good reason to use the present term. Edison 22:30, 15 March 2007 (UTC)

Residual current devices are called as such in New Zealand, and presumably, Australia as well because we routinely purchase each other country's brands for such devices. --JNZ 21:21, 19 July 2007 (UTC)

Object Tabby (talk) 23:09, 7 December 2007 (UTC)

A GFI is a different device to an RCD. It has a second coil attached to the main sensor coil around the supply conductors. This enables a GFI to detect and trip on detecting a neutral (grounded wire)-to-earth fault. GFIs are covered by a different standard (UL943) which incorporate tests for the neutral-to-earth fault. Strictly speaking, there should be a separate entry on GFIs. --Kiwigpz (talk) 09:45, 27 December 2007 (UTC)

Do you have a ref for what standard RCDs are covered by in that same set of standards? And for the different arrangement of current sensing coils? GFI and RCD seem to be the same thing. Edison (talk) 06:15, 28 December 2007 (UTC)

There are no US, Canadian or Mexican standards that I know of for RCDs, only GFIs - I stand to be corrected on that as I have worked only on GFCIs for the US market. Internationally for RCDs, there is IEC61540 http://webstore.iec.ch/webstore/webstore.nsf/artnum/023695?opendocument, IEC61008 http://webstore.iec.ch/webstore/webstore.nsf/artnum/036223?opendocument, and IEC60755 http://webstore.iec.ch/webstore/webstore.nsf/artnum/034162?opendocument. Australia and NZ use AS/NZS3190 http://www.saiglobal.com/shop/Script/Details.asp?DocN=AS037588948321 as well as local adoptions of IEC 61008. The UK uses BS 7288 and BS 7071. All these standards refer to RCDs - not GFIs. It's interesting to note that 120V countries seem to use GFIs and never RCDs and 230V countries use RCDs and never GFIs - don't know why. If you follow this link http://www.fairchildsemi.com/ds/RV%2FRV4145A.pdf to the datasheet for the chip that is used by most electronic GFIs and RCDs (my opinion) you will see on page 4 a nice description of the differences in the circuit to give the different operation. Figures 2 & 3 show the standard circuits - you will see two coils in the GFI and one in the RCD.--Kiwigpz (talk) 10:23, 28 December 2007 (UTC)

I am trying to determin if the RCD and GFI are really different devices, or if it is just regional terminology difference. This afects how the article should be set up, or if there should be two articles. The standards referred to by Kiwigpz are only viewable in a preview format without paying a large sum, so the test standards are not viewable to determine the trip and nontrip conditions the RCD and GFI must satisfy. The chip data sheet shows first a circuit for a 2 wire ungrounded outlet which would trip if the neutral and phase currents differ sufficiently, as would be the case for a phase to ground leak, or a leak to the protected circuit's neutral from a different source (less of a concern). The arrangement for a three wire grounded outlet apparently provides for tripping if there is a low resistance connection between the neutral and the ground prongs of the outlet. Are you saying that the first trip condition is also characteristic of a RCD but it lacks the second trip condition? I am looking for the trip/notrip conditions for the two devices (if they are in fact different). Edison (talk) 17:31, 28 December 2007 (UTC)

Yes, to my knowledge, no RCD will trip on a neutral-to-earth fault. Sorry but I have no other references to back that up - just the standards listed. UL943 contains the test for the neutral-to-earth fault that GFCIs will pass, none of the RCD standards do. I will try to find a reference that confirms that.--Kiwigpz (talk) 09:52, 29 December 2007 (UTC)

I don't understand from your link to the RV4145A how it works when there's a neutral-to-earth fault. What is a "magnetic path between the sense transformer and the grounded neutral transformer"? How does this result in an "AC coupling" that closes a positive feedback loop around the op-amp? Eric Kvaalen (talk) 17:32, 2 August 2008 (UTC)

As well as I know, it is usual for European RCD to trip at 30ma, and US GFIs to trip at 5ma. That doesn't mean that the names are actually indicative of that, though. I don't know what the WP:MOS rule is regarding US vs. other countries and work usage. Gah4 (talk) 21:17, 7 March 2021 (UTC)

Naming on the basis of google results is a dubious approach in any case. Not only does it bias Wikipedia towards the nomenclature of dominant countries on the internet (i.e. the USA), but in cases like this, there are abbreviations which are used far more often than the spelled-out terms. e.g. a google for "RCD electric" turns up 710,000 results. 85.158.45.40 (talk) 01:12, 15 February 2011 (UTC)

Did you notice the dates on the thread? How about ELCB? What do you non-North-Americans call these things again? --Wtshymanski (talk) 01:32, 15 February 2011 (UTC)

Afaik RCD is the term used in international standards, produced by the IEC, which should rightly trump any country-specific terms. DiscreetParrot (talk) 00:02, 21 January 2025 (UTC)

Surge resistance

I do not understand the section entitled "Surge current resistance [in A]":

Peak current an RCD is designed to withstand (8/20 µs impulse). The IEC 61008 and IEC 61009 standards impose the use of a 0.5 µs/ 100 kHz damped oscillator wave (ring wave) to test the ability of residual current protection devices to withstand operational discharges with a peak current equal to 200 A. With regard to atmospheric discharges, IEC 61008 and 61009 standards establish the 8/20 µs surge current test with 3000 A peak current but limit the requirement to RCDs classified as Selective.

What is an 8/20 µs impulse? What is a "0.5 µs/ 100 kHz damped oscillator wave (ring wave)"? (Note that 100 kHz has a period of 10 μs.) What atmospheric discharge is it talking about? What exactly do IEC 61008 and 61009 concern, respectively?

Eric Kvaalen (talk) 17:32, 2 August 2008 (UTC)

I've rephrased that first sentence, it was unforgiveably jargon-y for a general reference encyclopedia. The 8/20 us impulse refers to a common shape of pulse used for electrical testing. --Wtshymanski (talk) 19:45, 2 August 2008 (UTC)

Bigger picture of internals of RCD needed

The current picture of the internals of the RCD is quite small, a larger picture would be nice. —Preceding unsigned comment added by 89.236.35.232 (talk) 13:20, 14 April 2009 (UTC)

3-phase picture

in the picture test button winding is incorrectly connected only to one side of torroid (both are up)-supposed to connect on one to up - other to the lower side —Preceding unsigned comment added by 88.196.129.215 (talk) 22:27, 16 June 2010 (UTC)

3-phase picture(corrected one)

3-phase.JPG —Preceding unsigned comment added by 88.196.129.215 (talk) 22:58, 16 June 2010 (UTC)

Great write ups regarding residual current devices however sensitivity can be higher than 300mA free standing electronic rcds with seperate cts for used for higher currents (usually up to 800A)have adustable sensitivity from as little as 10mA up to 2 amps (depending on the manufacturer).The protective circuit breaker (mccb ar acb) is tripped by means of an undervoltage/shunt release.Small modular rcbs for use with miniature circuit breakers have integral cts (or toroids)and are available with a sensitivity of up to 500mA. Dave Smith Maidstone UK. —Preceding unsigned comment added by 82.34.164.204 (talk) 15:32, 30 August 2010 (UTC)

Passive/active/latching/non-latching - cutting the Gordian knot

We've had a CN tag on that section for almost a year. There was a copy of one manufacturer's brochure for an RCD offered as an example, but strangely, none of the books I've found so far on Google Books talks about two types of RCDs. This makes me suspicious that it may be a peculiar offering by one manufacturer, and not necessarily standard practice. (North American GFCIs, to the limit of my knowledge, don't pay any attention to power interruptions and only trip for ground fault current. Perhaps North American practcies put the responsiblity for not restarting on power restoration in the standards for the connected equipment, and not on the GFCI's mandate? Seems a little weird to me to combine these two functions in the RCD). I've taken the section out. If someone finds a good authoritative reference that classifies two types, please restore that section with a good citation. --Wtshymanski (talk) 14:02, 19 August 2011 (UTC)

As well as I know, this is a European thing. I am not so sure why it is connected, but certainly in some cases being surprised by power restoration is bad. One might turn on some device, forget that it is on, and then leave it. As well as I know, rare in the US. Gah4 (talk) 21:28, 7 March 2021 (UTC)

2 errors

Whole installations on a single RCD, common in the UK, are prone to nuisance trips that can cause safety problems with loss of lighting and defrosting of food. RCDs also cause nuisance trips with appliances where earth leakage is common and not a cause of injury or mortality, such as water heaters. However such nuisance trips are easily corrected by removing the problem (such as a blown light bulb) and re-setting the RCD.

The last sentence is quite incorrect

1. blown lightbulbs are open circuit loads, removing them has nothing to do with resolving earth leakage issues
2. problems causing RCD trips are known for being not easy to correct, generally speaking
3. In the case of water heater leakage, it would be unrealistic to describe the solution as easily corrected and reset the rcd.

So I removed the faulty sentence.

This RCD contains a resistor with an improper value in the test circuit, which gives incorrect results for testing. Under certain circumstances it may prove lethal because it will not trip when expected. That is why RCDs should be tested by the socket tester with calibrated leakage

This makes little sense. I've not corrected it, as I didn't know what point the author. was trying to make. Tabby (talk)

As well as I know, tradition is for 5ma in the US and 30ma in Europe. Though with the different line voltage and plugs, people won't be using testers in the wrong system. Gah4 (talk) 21:31, 7 March 2021 (UTC)

What is an MCB?

"MCB" is not a universal explanation of a circuit breaker. Professional electricians across North America will never run into that terminology unless they speak with an electrician outside of that area. "MCB" should be linked to a correct page or explained as to what it is. — Preceding unsigned comment added by 208.65.73.107 (talk) 21:36, 28 February 2013 (UTC)

The term MCB (for Main Circuit Breaker) is widely used here in California in electrical power engineering. 173.164.209.28 (talk) 23:42, 4 December 2019 (UTC)

Although that's not what it means (in this article, at least). Andy Dingley (talk) 19:56, 16 December 2019 (UTC)

History Section Query

In the History section it is stated "In the early 1970s most North American GFCI devices were of the circuit breaker type. GFCIs built into the outlet receptacle became commonplace beginning in the 1980s. The circuit breaker type, installed into a distribution panel, suffered from accidental trips mainly caused by poor or inconsistent insulation on the wiring. False trips were frequent when insulation problems were compounded by long circuit lengths. So much current leaked along the length of the conductors' insulation that the breaker might trip with the slightest increase of current imbalance. The migration to outlet receptacle based protection in North American installations reduced the accidental trips and provided obvious verification that wet areas were under electrical code-required protection."

I find it difficult to believe that the insulation on the wiring in North American premises was so poor that GFCI circuit breakers installed at the distribution panel were "falsely" tripped by the leakage and that it was necessary to resort to the installation of (multiple) CFGI devices at the outlet receptacles to get over this problem. (Yet in Europe, and elsewhere, RCDs and RCBOs are normally installed at the distribution board without problems.)

If the above "History" true, this would seem to be an indictment of the quality of the insulation of North American cabling. I submit that in most countries, if it were found that when a GFCI, RCD or RCBO was installed it detected leakage of sufficient magnitude to cause it to "trip", the authority concerned would deem it to be a fault condition that required the replacement of the wiring concerned. Such wiring would not pass the normal (Megger) Insulation Resistance Tests. Fredquint (talk) 15:19, 13 May 2014 (UTC)

I remember stories about the early GFCI trip set at 1ma, and that caused too many problem. It was then changed to 5ma. Circuit breaker type are and were always much more expensive. I believe commonly used for bathrooms and showers in commercial settings, but rarely for home use. PVC wiring should have small enough leakage, but some older wiring might be leakier. Gah4 (talk) 21:35, 7 March 2021 (UTC)

History section correct?

The history section in the german version of this article ("Fehlerstromschutzschalte") goes back quite a bit further than to south africa 1955:

Der Fehlerstromschutzschalter wurde bereits 1903 von Schuckert unter der Bezeichnung Summenstromschaltung zur Erdschlusserfassung patentiert (DRP-Nr. 160.069).[20] Kuhlmann beschreibt bei AEG eine Methode zur Messung der Erdschlussströme im Berliner Netz. Weiterentwickelt wird die Technik, auf der auch heutige Fehlerstromschutzschalter basieren, von Nicholsen (1908, USA-Pat-Nr. 959.787).[21]

Maybe this should be revised in the english article? — Preceding unsigned comment added by 159.168.7.148 (talk) 10:36, 8 April 2013 (UTC)

A translation from the current article de.wikipedia.org/wiki/Fehlerstromschutzschalter is given below "The residual current circuit breaker was already 1903 patented by Schuckert under the name Total Current for Earth Fault Detection Circuit ( DRP No.. 160 069). [23] Kuhlmann describes AEG a method for measuring the earth fault currents in the Berlin network. Is further developed the technology, on which also present residual current circuit breakers are based, by Nicholson (1908, U.S. Pat no. 959 787). [24] In the early 1950s, after countless suggestions and technical studies on the basic applicability of the circuit for the first time presented as a protective device a mature residual current circuit breakers for wide use in the current client. [25] Busy is in it for 1951 a residual current circuit breaker of the company protection devices Society & Co. mbH. KG, Schalksmuehle / Westphalia. (Schupa) with the trade name cobweb , [26] which was designed in two-, three-and four-pole version for a nominal current of 25 A and voltages up to 380 V with a tripping fault current of 0.3A. A lower trigger threshold was discussed but rejected as economically unsound. The time allowable leakage in heating devices have resulted in a lower trigger threshold also in frequent false alarms. In the year 1957 by Gottfried Meier Biegel in Austria at Felten & Guilleaume a residual current circuit breaker. These were prescribed in Austria in 1980 in private households by law, the trip current was gradually reduced from the original 100 mA at 70, 65 and 30 mA. Since early 1985, this applies to the entry into force of the provision SEV 1000-1.1985 in Switzerland."

Fredquint (talk) 16:09, 13 May 2014 (UTC)

Use of RCDs for protection against shorts to earth

Undid revision 588089932 by TinyMark (talk) RCDs are used for earth fault protection. See talk.

RCDs are very much used for protection against short circuits to earth. See below link for reference. In the case of TT installations, where there is no metallic earth return to the supply transformer, the earth loop impedance may be too high to trip a circuit breaker, which is why RCDs are used for additional protection, typically with a 100 or 500 mA trip current, as compared to the 30 mA typically used for protection against electric shock.

http://www05.abb.com/global/scot/scot209.nsf/veritydisplay/c4e584f06cc6c4fbc1257ad800496193/$file/2CSC420004B0201_RCDs%20EN.pdf

I'm having problems with the terminology here. I must admit that I never had anything to do with these things when I lived in the UK. But surely, in a TT system, the circuit cannot be shorted to earth because a the circuit is not shorted, i.e. the current does not return directly to where it came from????? TINYMARK 12:14, 29 December 2013 (UTC)

If I recall the regulations do not use the term short circuit; it is simply referred to as a fault. But short circuit defines the term as current flowing along an unintended path, which is what happens - in the event of such a fault the current flows directly through the mass of earth to the supply transformer (usually via the earth electrodes). It's not relevant that that path isn't a metallic path. The RCD is used because depending on the local conditions the fault current may be only a few amps, which means a normal circuit breaker could take a long time to trip, or not trip at all. The circuit breaker is still relevant and used to provide overload protection and protection from phase-phase or phase-neutral faults. Alistair1978 (talk) 12:28, 29 December 2013 (UTC)

Well I have been living in Germany for ages now. The circuit breakers are marked with LS (Leitungsschutz) meaning that they are there to protect the power cable - from burning out or causing a fire, I assume. This will not happen with a higher resistance short as you described as the current is too low. Although a fault is present and the RCD will trip - but what is being protected??? TINYMARK 12:52, 29 December 2013 (UTC)

It's for preventing fire at the location of the fault (see page 16 of the PDF linked above). Otherwise, a fault to earth could deliver say 10 amps continuously, which might not melt the supply cabling but could easily cause a fire at the point of fault, as well as causing rise of earth potential which could cause a risk of electric shock. Note that such TT supplies are very common in the UK in rural installations with overhead supplies. Alistair1978 (talk) 14:19, 29 December 2013 (UTC)

Thanks Alistair. My mum's flat is on the first (top) floor of a house and I (2m) could reach up and touch the lines coming into the house! Obviously a TT system, but with very iffy plastic sleeves on the lines. In Germany TT systems are usually only in factories etc. TINYMARK 15:36, 29 December 2013 (UTC)

Lead opening sentence is iffy

A residual-current device (RCD), or residual-current circuit breaker (RCCB), is a device that instantly breaks an electric circuit to prevent serious harm from an ongoing electric shock. A fuse or circuit breaker also does that, 'instantly' of course, is subject to qualification. How fast a fuse or breaker reacts depends on its profile and the degree of overcurrent in the circuit. They can be made as fact as they need to be. An RCD also has a reaction time that can vary. Actually, it needn't be any faster than a breaker. That's not how it protects against electrocution. That sentence is bad; it misses the issue. Sbalfour (talk) 23:51, 14 November 2017 (UTC)

RCCB full form is Resudual case circuit breaker which are used in industry for prevent from electrical shock to human or animals.Its working sensing by current.Its woking principal of RCCB is its opeated when current is unbalanced from phase or netural . — Preceding unsigned comment added by 165.225.106.51 (talk) 09:21, 13 July 2018 (UTC)

Article Title

What is with this article title? Why does GFI/GFCI redirect here? As far as I know, RCD is only used in the UK and Australia. The US and Canadian population vastly outnumbers these countries. Having GFCI redirect here might confuse more people than if it were the other way around. 24.194.179.228 (talk) 05:38, 16 May 2019 (UTC)

I don't know the WP:MOS rule, but I don't think it is meant to give greater weight to US usage. Gah4 (talk) 21:40, 7 March 2021 (UTC)

Afaik RCD is the term used in international standards, produced by the IEC, which should rightly trump any country-specific terms. DiscreetParrot (talk) 00:01, 21 January 2025 (UTC)

LCDI

It seems that there is now LCDI, Leakage Current Detector Interrupter, designed to detect faulty power cords. They are required for some portable air conditioners. My understanding is that they put some wire mesh inside the power cord, and outside the actual conductors. If current goes into it, then there is a fault in the cord. That seems somewhat different from RCD or GFI, but maybe it could redirect here. It seems like they can also use Arc Fault Detectors instead, which I think are not well described here, but might be, or might have their own article. Gah4 (talk) 09:57, 20 March 2021 (UTC)

Is there an official definition of an LCDI somewhere, perhaps in the requirements for its presence in certain appliances such as air conditioners? My current understanding of an LCDI is that it is a dedicated GFCI installed together with a mesh-shielded power cord. Please correct or refine this impression if necessary. Reify-tech (talk) 15:07, 23 September 2021 (UTC)

is this wording correct?

"Any difference between the currents in these conductors indicates leakage current, which presents a shock hazard."

there MUST be a leakage current for there to be a difference.

a leakage current is not a shock hazard, but it indicates a possible shock being in progress

Can we please have a citation for a claim in the second paragraph?

Hi,

The second paragraph has the claim:

"Alternating 120-volt current above 20 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."

Where is the citation for this?

Thank you, James Pedersen— Preceding unsigned comment added by Watcher00090 (talk • contribs) 03:11, 23 March 2022 (UTC)

Motors

No mention of how certain devices such as certain styles of electric motors causing nuisance trips? 71.173.19.20 (talk) 15:33, 6 June 2022 (UTC)

Type A-SI

There is no mention of SI (super immunised) RCDs. My understanding is that these are a subclass of Type A RCDs, but that they provide more resistance to nuisance tripping. I have no idea whether these are standardised, or whether they are manufacturer-specific. As a result I am hesitant to add this type to the article since I don't have access to the IEC standard. Found these links though: https://www.farnell.com/datasheets/607776.pdf https://www.electrical-installation.org/enwiki/Sensitivity_of_RCDs_to_disturbances JanCeuleers (talk) 17:35, 18 March 2023 (UTC)

uni or bi directional RCDs

There is no discussion of this topic which is becoming important in solar installations where the current can flow in either direction. Apparently some types of RCD are unidirectional and some bidirectional. It would be good for wikipedia to cover this if possible. I do not know enough to provide any guidance. 31.185.161.39 (talk) 22:24, 10 May 2024 (UTC)

Added mention! DiscreetParrot (talk) 02:25, 21 January 2025 (UTC)

History

The history section focusses heavily on the invention of the American GFCI. RCDs are a mere footnote at the end and it completely misses the development of the voltage-operated ELCB that preceded the RCD. Both voltage-operated ELCBs and RCDs are types of ELCB, as discussed in the ELCB article, and thus presumably GFCI too, so really the best place for this background history of developing earth leakage protection technology from which specific devices were born, is actually the ELCB page.

Though I figure some may argue that a GFCI is not a circuit breaker, so maybe the ELCB article would need renaming to 'earth leakage protection system/technology' or something, and ELCB would then be a redirect to it.

Edit: After a quick bit of googling it's now clear to me that GFCI is essentially a technology and can exist within either a circuit breaker or a 'receptacle'/socket, just like RCD technology. So I feel that it would indeed be a good idea to both clarify that within this article, and to rename and rework the ELCB article so it's no longer circuit-breaker specific. Going to work on that now. DiscreetParrot (talk) 07:03, 21 January 2025 (UTC)

Update, I went ahead and renamed the ELCB page, I'll come back to think about further changes after sleep. DiscreetParrot (talk) 08:10, 21 January 2025 (UTC)