This is an archive of past discussions about AC power plugs and sockets. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.
Ambiguity of some terms
Hi everybody.
I am working on a translation of this article into German. At a first glance I found two things I do not quite understand.
The first one is that about the "British site isolation transformer". What is it exactly? Does it isolate whole sites — e.g. buildings, industrial zones — from the general neutral level, or is it just used "on site" to do this work for a restricted number of connected devices. While it's rather obvious why it could be done in the second case — what should it be good for in the first one? Or is this already the answer to my question? I checked it on google, but I only get the info that a site isolation transformer is a "big yellow thing". And that's not even a British one. Not very informative.
The second ambiguity is in the paragraph on the NEMA 2-15, 2-20, and 2-30 plugs. There it says "The 2-15 has both pins rotated 90 degrees; the 2-20 has one pin rotated 90 degrees, and the 2-30 is rotated." So, in how far is the 2-30 rotated, then?
Any helpful answers are welcome.
ok the first question i can answer the trnansformers are used to run power tools on building sites and give an output of 110V centre tapped (so each side of the output is at 55V relative to earth) the output sockets are usually of the IEC 309 110V industrial variety on the smaller transformers usually the 16A
as to the second question i've looked at an external link that lists it (look at the links on industrial and multiphase power plugs) but im unsure on the meaning of the diagrams there probablly best if an american answers that one Plugwash 18:10, 14 Nov 2004 (UTC)
Thanks for your quick answer. Well, what you say about the isolation transformers makes a lot of sense. You get a voltage below the critical 60 V relative to earth and can run 110V devices.
As for the 2-30: in the diagrams linked under lots of diagrams of non-locking american recepticles the 2-30 looks very much like the 1-15 as the positions of the pins is concerned. So we'd really better wait for an "insider" to get it right. I think this should also be put right in the article.
ok i've decided to comment it out of the english version of the article for now until someone can fix it. I think its a pretty rare type anyway if some american who has heared of it wants to put it back with proper information then i welcome them doing so. if you are going to make a translation of this page then its probablly best to keep it on your watchlist so you can migrate improvements over. Plugwash 19:46, 16 Nov 2004 (UTC)
The NEMA 2-15, 2-20, and 2-30 devices are essentially dead. What we now call the 2-15 was once a common device in the 1920s or thereabouts. All of these have been superseded by grounding versions. I have never seen any of these devices installed in the real world. I am a licensed electrician practicing in Texas. Yak9922:39, 22 April 2007 (UTC)yak99
Undefined term
Re Safety notes second item:
What is an RCD? Safety notes need to be written for the very ignorant.
It is defined near the beginning of the article. See Domestic AC power plugs and sockets#Earth/Ground. Now I moved the definition to the very first use. Probably the abbreviation should be linked again at the end of the article when it is so far from the first use of the term. What do you think? Next time please try to use the search function of your browser and RCD gives you the explanation too. --pabouk01:28, 2 December 2006 (UTC)
Isn't the last part of this statement, 'just trying to make life difficult for the Brits' extremely racist or at the very least guilty of flaming? I am offended and I am a British republican! —Preceding unsigned comment added by 86.150.251.249 (talk) 09:52, 7 April 2008 (UTC)
The discussion centered around the abbreviation RCD and whether it stood for Residual Current Device or Royal Canadian Dragoons. I haven't made life nearly as difficult for the Brits as my ancestors did when they were there raping, pillaging, murdering and burning a thousand years or so ago. As a consequence of all that raping, we're basically the same race so I don't see how the accusation of racism applies. I don't mind British pretensions as long as they don't mind me laughing at them ... RockyMtnGuy (talk) 18:14, 8 April 2008 (UTC)
French plug
seems we have no pictures of french plugs (i mean plugs for france only NOT the CEE 7/7 combo plugs)
i tried looking at the french wikipedia but i don't speak french and was unable to find anything even with the help of autotranslators.
anyone here able to produce such a photo? Plugwash 00:27, 12 Dec 2004 (UTC)
Well i found someone in the end after much pestering of people in #fr.wikipedia on freenode Plugwash 10:07, 6 Apr 2005 (UTC)
I'm writing and translating the french page of this article. I also add many details. The french plugs are C and E type and the earth picture details are on commons or on the french pictures:
The plugs listed here are used for normal appliances in most situations NOT merely in domestic situatations. I propose the title of General purpose AC power plugs and sockets. any comments? Plugwash 18:51, 30 Dec 2004 (UTC)
Why not just "AC power plugs and sockets"? Gene Nygaard 19:12, 30 Dec 2004 (UTC)
All the relevant IEC standards [1] make a clear distinction in their title between "domestic and similar general use" or "household and similar purposes" plugs on one side and "industrial purposes" on the other. The "domestic" ones are generally intended for currents below 16 A and single-phase applications where there is only one single voltage and frequency. The "industrial" ones are designed for higher currents, possibly multi-phase, higher mechanical robustness, and with coding systems to allow the safe coexistance of different voltages and different frequencies on sockets in the same building. So if you don't like the "domestic" in the title, it could in principle be expanded to "domestic and general-purpose". However, I prefer to simply leave it as it is. Markus Kuhn17:29, 24 May 2005 (UTC)
Not sure i was considering that one but then i thought about pages like industrial and multiphase plugs and sockets.
Another possibility would be to split this article putting the general section (stuff that isn't specifc to plug type) at "AC power plugs and sockets" and then having the actual socket types split between "general purpose AC power plugs and sockets" and "Industrial & multiphase power plugs & sockets". Im not sure what the procedure for making a major split of a featured article is though. Do both become features one become featured or neither become featured?
I think things should stay as they are. Chamaeleon 16:16, 10 Jan 2005 (UTC)
The article says The situation in the United Kingdom is slightly more clear-cut, with BS 1363 plugs (3 to 13 amperes, depending on the fuse inside) almost universal in homes.. One reference I have(Boy Electrican, 8th ed., 1965) says there were up until 1950 three sizes of round-pin plugs (2 A, 5 A and 15 A) and since that time a single 13-A plug with flat pins. This doesn't sound very clear to me at all; in the US and Canada I can travel from St. John's to Victoria, from Iqaluit to El Paso, 20 million square kilometres, in buildings where the paint is still wet down to homes that got knob-and-tube wiring during the Great Depression, and any appliance small enough to lift will plug in without adapters. How prevalent are old-style plugs in UK homes? Do British appliances still come without plugs? --Wtshymanski16:45, 24 May 2005 (UTC)
All British appliances come today with a BS 1363 plug fitted to the chord. However, the cords all come with a warning label that explains the colouring scheme of the chord to anyone who thinks they must replace the plug. This may have been a sensible idea 30 years ago, but is today a ridiculous anachronism. IMHO, it is time the relevant standard gets updated. Markus Kuhn17:29, 24 May 2005 (UTC)
2 5 and 15A bs546 plugs are still seen in the uk although more often than not in specialist applications. but i still thik its sensible having stickers that explain the color scheme for anyone who does need to put a new plug on. for example they may want to fit an IEC plug to fit thier ups or a waterproof plug for outdoor use or simply fit a new 13A plug after cutting the original off to thread the flex through a small hole in a shelf worksurface or whatever. Plugwash 00:25, 8 Jun 2005 (UTC)
I remember seeing BS1363 to BS546 adapters (homemade) when I was in the UK, back in 1990. I hear they're not so common now. As to the prevalence of a single standard in the USA and Canada, what about the grounding (NEMA 5-15 and Canadian equivalent) that didn't become standard until after 1962 or so? What about the confusion involved with "cheater plugs"? Yak9922:22, 22 April 2007 (UTC)yak99
It seems to me that the heading of "Domestic Plugs and Sockets" is justified. Yes, it's true that these configurations are found in industrial and commercial settings, but this is a general article which is likely to be consulted by persons wishing to know the standards in a particular country for the 99%+ of electrical appliances covered by the most common standard. Here in the US, there are a couple of dozen receptacle standards, but a guest here will be perfectly covered if he or she brings a NEMA 1 or NEMA 5 adapter. Polyphase and industrial standards belong in other articles. Yak9922:22, 22 April 2007 (UTC)yak99
This is called a "Domestic" lalala because the page was started by someone with that regional colloquiolism, just as British people like to refer to the mains where we Americans refer to the power line.
This same person was probably responsible for the section of the power supply article which used to refer to a domestic mains adapter which I have renamed to just AC adapter. A Google search for "domestic mains adapter" turned up about 8 hits across the entire planet and half of those hits were just links back to the wikipedia article.
There isn't any good reason to make a distinction between "home based" and "industrial" products because commercial businesses and industry make no such distinction. "home based" plugs are used in every business and industrial setting anyway for low amperage devices so they are not purely domestic. In the same way businesses and industry use "domestic" voltages in their offices and for general power so it's not domestic only either.
In general the naming of this as "domestic" is meaningless and should be removed from this article title. Just because this article has retained that undescriptive word in the title for so long does not give it a "historical significance" of needing to stay in the article title.
I will move the article to "AC power plugs and sockets" and turn this page into a redirect, unless someone can give a really clear reason for why it should stay this way. DMahalko (talk) 16:24, 14 May 2008 (UTC)
The industrial plug page is humorous in that it spends 1/3rd of its time discussing European only standards and then the rest of the page is north american which makes no such distinction between industrial and domestic and so should not be there but over here.
These articles are a mess and need to be merged into one, with a section discussing European "domestic/industrial classifications" and then another section which is North American that simply classifies them all together.
Yet another reason why I think the British just ought to have their own en-uk encyclopaedia because so much stuff is weirdly different in strange little ways from American standards -- and I'm sure they have to say the same for us Americans. DMahalko (talk) 16:33, 14 May 2008 (UTC)
There is no real split between domestic and industrial plugs & sockets, obviously common plugs & sockets used in the home will be used in industry too. And the other way round sometimes, some people have "site isolation transformers" for powering low-voltage tools at home. These use the yellow "commando" plugs & sockets which aren't very common in domestic settings. I think the split between the two articles is about right, but maybe different names are needed? "Common" or "General use" might be a better description, and they appear in the IEC standard as mentioned above. The other article could be called "high power" or "high current", as that's what they are for? Maybe a third page for "un-common"? Or does that already exist? I'm thinking for, for example, the Australian 15 A 250 V plug & socket which is fairly common but probably not common enough to warrant more than a small mention in this article. Then there's the Australian 10 A 250 V with a round earth pin/hole. That's not common at all. Then there's all the variations on the NEMA plugs & sockets. I think they have their own page though so that's ok. I'd probably say that the NEMA 20 A 120 V plug & socket is about as common as the Australian 15 A 250 V plug & socket so would deserve a mention and link for more information. Ziltro (talk) 21:03, 20 May 2008 (UTC)
Contributors to this page should probably take a look at Light switch, which at the moment is almost entirely about switches in the United States. Jooler 09:02, 10 Jan 2005 (UTC)
seen it and it needs ome form of reconcilation with switch but im not sure what yet. (i think this was an unsigned comment of mine but i don't remember for sure Plugwash)
Edison Plug
The Type A and B connectors (American 2 and 3 pin) are frequently (at least in the theater and film industries) referred to as "Edison plugs". This information doesn't appear anywhere else on Wikipedia. Would it be appropriate to add it here, or perhaps create a page on theater and film terminology? Guido del Confuso 02:19 2005-Jan-15 (UTC)
I would want to see sources backing this up. The name seems like a misnomer which makes me dubious about the inclusion of this without strong sources. Plugwash 02:22, 15 Jan 2005 (UTC)
Hmmm... I'm not sure where the term comes from, but I know that it is regularly used in film and theater. A Google search for "Edison plug" turns up about 1500 (mostly theater equipment related) hits, and "Edison connector" turns up almost 300 more. My guess is that it has something to do with the Edison power company rather than Thomas Edison himself. Guido del Confuso 05:26 2005-Jan-15 (UTC)
I've added this information to the section about type B. Is it definitely also used for type A? I did a Google search and it seemed to refer to type B. What do you mean by "theater": actual theatres, or cinemas? I don't know of the Edison Power Company. Is it big in the US? Is it likely that the term comes from them? Chamaeleon 11:45, 15 Jan 2005 (UTC)
Well, the truth is that most people in the US don't make much of a distinction between the grounded type and the ungrounded type of plug. More often than not "Edison plug" will refer to the three pin kind because that's what's generally used, but people will also use it to refer to the two pin kind. This is as opposed to, say, twist-lock [2] or stage pin [3] which are the most frequently used connectors for lighting equipment. By theater I mean actual theaters where plays are performed. My guess is that the term actually originates in theater: Consolidated Edison provides electricity for most of New York City--the major center of theater production in the US. The term "Edison" was therefore used to refer to the sort of "generic" power connector you might find that could plug into anyone's wall outlet. Again, this is just a guess as to the name--theater and film etymology, like most etymology of slang and professional terms, is shrouded in mystery. Guido del Confuso 23:57 2005-Jan-15 (UTC)
I'm just adding my confirmation of this fact -- "normal" US household connectors are called "Edison plugs" in theatre settings. This is almost universally true in the US -- nearly any stagehand who works with electrics will understand what you mean. It is especially used to distinguish from "stage pin" and "twist-lock" connectors, as a theatrical production may use any or all of those (my show, for example, uses Edison connectors for moving lights, stage pin connectors for conventionals, and twist-lock for special FX lights.) kmccoy(talk) 03:09, 16 Jun 2005 (UTC)
I am a licensed electrician practicing in Texas. To me, an "Edison" plug is anything using the North American standard light bulb thread (i.e. the "Edison base"). For example, a "plug fuse" is an "Edison base" unless permanently modified by a Type S adapter. The term "Edison plug", when used to identify a NEMA 1 or NEMA 5 device, should be clearly identified as a theater term.
Anyone happen to have information on when each plug type was put into use?
Type I (Australian 2/3-pin)
I'd like to mention that Australian plugs have insulated pins (and have had for a few years) but I'm unsure about removing the information on the regulations (perhaps it should be left in) - Diceman 15:08, 12 Apr 2005 (UTC)
Case ground via neutral
In the US only the cases of clothes dryers and cooking appliances were permitted to be grounded to the neutral. Though I have no cite for it, I've read somewhere ( probably on the Mike Holt Web site) that this was meant to save copper during WWII. Since the 1996 revision of the U.S. NEC it is no longer permitted for new installations. It was misleading for the article to say that "appliances" in general used the neutral for grounding and I have removed that sentence for this reason. Typical 2-wire portable devices like lighting, etc. didn't use a case ground. No portable appliance could ever rely on the return pin actually being near earth potential since there are innumerable ways to defeat this, even after the introduction of polarized plugs. Grounding of these cases to the neutral was not to my knowledge ever permitted in the Canadian electrical code, though the oldest copy I have access to is only from 1984.--Wtshymanski06:01, 25 May 2005 (UTC)
Very true, 240V outlets for clothes dryers and ranges were NEMA 10-30 and 10-50 (3 wire) with the neutral also used as the ground. After 1996 New installations had to be the NEMA 14-30 and 14-50 (4-wire) with separate neutral and ground. A new dryer or range purchased today in the U.S. can be wired for either standard. Dryers and ranges usually have 120V parts, such as timers and lights, that pull power from one leg of the system, making the shared neutral/ground a current carrying conductor. In general, the 10 standard is sufficiently safe, but the 14 standard is much better. In U.S. household panelboards/load centers, the neutral and ground from all circuits share the same bus. that bus is attached to a grounding rod and the neutral from the service entrance cable.JAK8316:08, 5 February 2007 (UTC)
It's not exactly correct to say that In U.S. household panelboards/load centers, the neutral and ground from all circuits share the same bus. This is only true at the Service Entrance; that's where neutral and the protective ground (earth ground) are bonded together. But everywhere downstream of that, the neutral and protective ground are entirely separate and the neutral bus is insulated from the case of the panelboard or load center. In my house, this is even true of my main load center because the "Service Entrance" point (and its associated "main breaker") is remoted from the main load center.
Yes, thank you for clarifying my oversight on that, the neutral and ground are separate until they reach the panel board. My house has a combo service disconnect which is also the main breaker. The neutral bus is bonded to the neutral service conductor and ground cable, and the panel is grounded via a jumper. It would be wise to have a separate ground and neutral bus, but only if the house is wired past the 1996 code when the NEC specified separate neutral and ground for 240V applications... JAK8318:00, 5 February 2007 (UTC)
A precis of the National Geographic article from the June 2005 issue: Harvey Hubbell patented a plug in 1904, eliminating the need for an electrican to hook up appliances. The US standardized on that plug in the early 1900's, but world-wide there are 13 different systems in use. European Union CENELEC hasn't yet standardized on a plug design, so sockets now take different types. Voltage and frequency are different, though everyone uses AC. A Hubbell employee says he hopes one day plugs will be standaradized the world round, but doesn't expect to see that in our lifetimes. There's a map showing 5 different zones of plug use, but the types and voltages aren't described. No facts worthy of adding to the Wikipedia article, in my opinion. --Wtshymanski16:16, 27 May 2005 (UTC)
Actually, the US never standardized on Harvey Hubbell's plug design. As far as I can tell from the patent drawing, it incorporated round pins. The only consistent standard in the US from about 1910 to the late '20s was the "Edison base" light bulb thread. Here is text from page 609 of the Fourth Edition of The American Electrician's Handbook (McGraw-Hill, 1936): "22C. Attachment Plugs were formerly made in a variety of designs. In general, a plug of each different design required a correspondingly-designed receptacle to engage it. Almost endless confusion resulted. But now, largely through the efforts of Electrical Merchandising, the Standard plug cap with parallel blades is almost univerally employed." Yak9922:02, 22 April 2007 (UTC)yak99
New title (& -> and)
Using "and" in a title is preferred: see naming conventions. I am in the process of cleaning up the redirects, etc. (I read and noted the previous discussion on page title, which didn't establish a clear favorite for "&"). DemiT/C 21:52, 2005 Jun 6 (UTC)
i kinda agree. i think the thing that put others off was after all the other comprimises the title was already very long. Plugwash 20:13, 13 Jun 2005 (UTC)
Many people may bring in electrical appliances from the Mainland of the People's Republic of China. These appliances come with a CPCS-CCC plug. Note that there is no British Standard adaptor can solve the teething problem between a BS1363 socket and a CPCS-CCC plug. Even though there are relevant adaptors on the market, they are not legally sold. Lacking a BS1362 fuse, safety shutter and irregular-shaped socket holes are the weaknesses of such adaptors. The Electrical and Mechanical Services Department discourages (not prohibit) bringing in appliances from the Mainland China. For safety, Hong Kong users of Mainland appliances must have their plug replaced with a BS1363 one, fitted with a suitably rated (3A, 5A, 13A) BS1362 fuse.
While the point is valid (if we're talking about a BS1363 30/32 Amp "Ring Circuit"), I'm not sure it's unique to Mainland Chinese gadgets brought into Hong Kong. It seems to me that the point must be equally true anywhere an appliance can be brought from a world-wide typical, low-amp branch circuit into a BS1363 30/32 Amp "Ring Circuit" environment. Should the point remain in this article? And if it should, whouldn't we write it to apply more generally?
go ahead and make it more general. — Chameleon 17:51, 13 Jun 2005 (UTC)
travel adaptors sold in the uk for visiters here are deffinately fused are you sure the ones sold in hong-kong for similar conversions are not? (i'd like photographic evidence of this since i find it very surprising). Plugwash 20:01, 13 Jun 2005 (UTC)
I know the BS5733 visitors' adaptor sold the UK. However, they are not sold in Hong Kong.
"Safety notes" section
The safety-notes section is now getting a bit out of hand. Some of the statements in it are plain wrong, others are at least questionable or exaggerated. Some are written in an imperative or advice style, which in itself is inappropriate for an encyclopedia. Some of it has bad grammar. Whoever feels strongly about this section, please keep in mind that you are editing an encyclopedia and not a travelers' guide or the like. If you make claims (e.g., about what is safe and what is not safe), then please do so only by quoting authoritative references. Make sure that the terminology you use sticks closely to that defined in the relevant standards documents. It is not the place of the Wikipedia to tell its readers what is acceptable use of plugs, but Wikipedia can provide pointers into authoritative literature (for example IEC standards) on that subject. I suggest that this entire article should stick closely to the content of the relevant IEC and regional standards and regulations, as opposed to becoming a wild collection of various contributor's personal opinions on the subject. There is a well-established body of literature on the safety of these plugs, based on peer-reviewed research and decades of accident statistics. We should summarize and quote that existing literature as encyclopedists, and not attempt to write our own amateur essays on the subject. Markus Kuhn 10:22, 20 Jun 2005 (UTC)
one anon made exccessive additions to that section with no backup at all which i have now reverted. what is there now is very basic and generalised advice on what to avoid without going into too many specifics (which would make a huge article in itself and probablly not one that is appropriate to wikipedia). Plugwash 22:43, 20 Jun 2005 (UTC)
I put my safety notes into discussion part for your reference.
Moreover, I previously made some additions to the safety note, which you guys think it is not very appropriate. But I believe that it is the case that many people do make mistakes in using adaptors.
Now I put the extra safety notes here. Please kindly do not delete. Interested readers can refer these articles. If you guys find the point made are incorrect or questionable, put your concerns here. In fact, most points made by me are reasonable, valid and worth-noticing for a travellers' guide but they are just not suitable for wikipedia.
I do think that some of the electrical travel advice on some tour guide books and discussion forums are not true or misleading, one of the books in China says:
You should bring an adaptor (from China) to the UK when you study there.
In fact, adaptors sold in China could not meet the relevant British Standards. They will leave the appliance unprotected by a BS1362 fuse.
And as a student studying electronic engineering (and an IEE student member) in an university in Hong Kong, I do see that so many exchange students (mainly non-engineering students) from China and overseas using adaptors inappropriately, at least could not meet the relevant British standards. And the examples below are the mistakes they made.
I have done some research work and read many relavent materials before editing this article of wikipedia.
Please put up with my English as I am not a native speaker. You guys can give me some recommendations on how to rewrite the essay. it would be better if there is a spell checker in wikipedia.
In the future, if I want to make a point or some 'travel advice' which is not appropriate for wikipedia, I will put it here for your reference.
British National (Overseas) from Hong Kong
Extra safety notes (for your reference)
In general, it is not advisable to bring electrical equipments from overseas countries.[4] Even the voltage and frequency of the equipment matches with your home system in some cases, you will probably need an adaptor or get your plug modified/replaced. However, improper modification of plug or wrong usage of adaptor (these cases are quite common as people failed to realise the not-so-obvious safety concerns) may lead to fatal consequences, for example, electric shock or fire.
If you study overseas, for safety reasons, you should purchase electrical equipments inside the country you are staying. And please refrain from bringing the equipment to you home country. Sell them to the local or international students (say at a car boot sale) staying there instead. Too many students make mistakes in using adaptors, which can be lethal.
This is hugely exaggerated, and is far too general anyway. It may be a fair comment for things like hairdryers and toasters, but would you seriously suggest that someone should give up a £1500 laptop computer because they may not know how to use an electrical adapter safely? 217.155.20.16313:51, 8 April 2006 (UTC)
Shaver adaptors sold in the UK are for shavers and electrical toothbrush only and should never be used for any other appliances. Never insert a Schuko or French plug into a shaver adaptor, as the fuse likely to be too weak and it is not possible to make the earth clip/strip of the plug make contact with the wiring system counterpart. Earthing is omitted in this way.
in much of europe its common to see houses with no earths on the sockets at all yet people happilly use class 1 equipment there all the time and you very rarely seem to hear about accidents caused by this . Plugwash 14:07, 22 Jun 2005 (UTC)
Common mistakes in plug modification include: (British system only)
Using a BS1362 13A fuse for the equipment that normally takes far less current (say 0.5A). Use a 3A or 5A fuse instead. See BS1363 for details.
The cord grip is not clamped on the outer layer of the power cable properly.
using a 13A fuse for a small appliance whilst bad practice is no worse protection than those exact same small appliances get when thier unfused europlugs are plugged into sockets elsewhere in the world which tend to be on 16A or 20A breakers afaict.
as for not getting the outer insulation in the cord grip again it is bad practice but before fitted plugs became the norm it was seen all the time and it didn't seem to be a huge issue. Plugwash 14:07, 22 Jun 2005 (UTC)
Examples of wrongly using an adaptor include:
An user in United Kingdom/Hong Kong inserts a Schuko or French plug into a BS1363 shaver adaptor (or an adaptor with BS546 5A sockets), then insert the adaptor into a wall outlet. The earth connection is omitted in this case. It cannot be overemphasised that "shaver adaptors" are for shavers only.
shavers only is a bit of an exaggeration. those adaptors are usually designed to take quite a variety of plugs including europlugs and 2 pin american plugs. but they are only suitable for use with small class 2 equipment (i often wonder who the f*** designed plugs with earth contacts done in such a way the plugs can be inserted into non-earthed sockets in the first place).
Some adaptors sold in Hong Kong are with irregular socket apertures and without a BS1362 fuse and without any safety shutters at the socket aperture.[5]
i don't seem to be able to access that site. yes there is almost certainly s*** out there but mentioning every specific case would lead to an insane ammount of text.
Note: The unfavorable language for wikipedia talk page is deleted, as ****. BN(O)
Extra safety notes for existing installations
Some caution is advised when working with existing installations, especially older structures with wiring that could date back decades. Formal standards may vary by jurisdiction, and may be commonly misunderstood, or outright ignored. More importantly, standards almost always change over time. Many of these changes occur when the old standards proved inadequate for safety. Older structures will often have several "generations" of wiring, with the oldest being of dubious safety by modern standards. New wiring may be improperly adapted to old wiring. Wiring can deteriorate over time. Safety features may be inadequate or bypassed. Conductors marked for safety grounding may not be properly connected to earth ground. Different installers may have different idiosyncrasies which, when combined, lead to trouble. Be alert, don't make assumptions, and test important safety features before depending on them.
First table
In the table that first appears (from top to bottom), there are two sections of the same title "Standard wire colours for wall sockets" but with different contents. Why?193.52.24.125 08:10, 25 Jun 2005 (UTC)
Looks like it just got mixed up on accident during an earlier edit. I've set it back. The first section is supposed to be for plugs, the second for sockets. Seems like it could probably be merged, though. Thanks for the catch. :) kmccoy(talk) 09:32, 25 Jun 2005 (UTC)
Plugwash, please refrain from using any undesirable language (even in form of X*** is not acceptable) in any page of wikipedia.
I retained your wording in your previous contributions because I didn't want to alter your meaning. It does not mean that you should use them in the future.
BN(O)
Warn for readers, and take care when translating
I'm writing the French article but the point will interest other langages: I must warn everyone that the English 'polarised' can mean different things. For example the plug do NOT have + and - polarisation. In French, for example, we have 2 words "Polarisée" (mean there's a + and a -, not the case with plugs) and "Détrompée" or "Détrompeur" (wich mean there's a non-symetrical shape to avoid inverting 2 slots). [NB "fiche (or, colloquially, plogue) polarisée is the usual term for polarised plug in Canadian French] the In English it seems there's not the equivalent for the second one.
So in english polarised may be also about anything else than +/- : computers connector, etc. About plugs in our case: Neutral and Live are the 2 slots to be distinguished. May be a bad word because some people think there's always a + and - with electricty and the Live is quite the same than a + BUT Live is not a + slot ! So that's why, after discussing with a friend, it seems better to try other words: "symetrical" for example seems better than unpolarised. The French "Détrompeur" do not seem to have a real equivalent, but "locating pin" will do the job. I think theses words will:
help people to forget the +/- question with plugs. (Some people say the current come "from" the Live and go to the Neutral: but in fact it changes 50 times a second !)
help translators (other langages Wiki) to avoid misunderstanding!
To me locating pin seems to imply a pin which only exists to polarise the plug which is certainly not the case with many polarised plug types. Plugwash18:20, 30 July 2005 (UTC)
I'm not expert with English and I can not be sure the new word is the best one. But I saw this "locating pin" expression in some (english speaking) datasheets. Maybe "non-symetrical" or "unsymetrical" are better to avoid this polarisation question ? (I hesitated, but my american friend make me choose locating pin) Today I may think a "locating Neutral" could be the best. I try the change. The important point to me is to avoid thinking about polarisating AC ;> (as well with your readers as with translators) fr:user:DC2
btw i don't speak french but i thought i'd take a look at the french article anyway to see if you had kept the structure and if you had any nice images ;). I noticed that you only have pictures with the french/german hybrid plugs in that article not the plugs that only fit one system Plugwash20:04, 30 July 2005 (UTC)
Do not want to add them because the article was explicit. Enought to understand some plugs may have only one earth system. Maybe I will whange my mind if I think this gives an illustration. But first some other works are needed at then end of the fr article. fr:user:DC2
I think if I see that a connector is "polarised" I would tend to think it means that it can only be inserted in one way, whether that is because of shape, size, layout of pins or the shape of the shell. --jmb12:43, 12 July 2006 (UTC)
Thank you for translating. In addition to "unsymmetrical", another English equivalent for "Détrompeur" I occasionally see is a "keyed socket", indicating that the socket is shaped so plugs (and only the right plugs) can only be put in the right way. --76.209.28.7217:23, 21 June 2007 (UTC)
In English, when something is "polarized" (or polarised) it has two opposite and mutually exclusive conditions. These may be "live" and "neutral"; or "positive" and "negative"; or "north" and "south"; or "capitalist" and "communist". When something (a device) is "keyed", it has a notch or grove or pin, usually made of metal, that enforces the correct use of the device. When you try to insert a plug into a socket with the wrong "polarity", the "key" stops you from doing so. In Type A plugs, the neutral connector is wider than the live connector and is the "key" which stops you from inserting the plug incorrectly. In Type B plugs the ground (earth) pin does two things. It is the ground (earth) connector, and also is another "key" to prevent the live and neutral connectors from being inserted incorrectly. The Type B socket has two different "keys" to stop incorrect insertion, one for Type A plugs and the other for Type B plugs. A better translation for détrompeur is "polarizing pin" or "pin which stops you from inserting neutral and live incorrectly". RockyMtnGuy18:11, 21 June 2007 (UTC)
IEC TR 60083 (the successor of the old CEE 7 document) assigns a number to each type of plug it lists. Perhaps the article should be structured according to IEC 60083, which is better maintained and more up-to-date than the US document mentioned. Unfortunately, it is a bit expensive to order. Markus Kuhn10:01, 31 July 2005 (UTC)
sounds like a reasonable idea but are there any details of this structure availible free or would the restructuring need to be done by someone who has the full document? Plugwash11:49, 31 July 2005 (UTC)
Separable Attachment Plug [6]
The drawing on this 1921 patent shows that the holes are to keep the plug in the socket more secureley. There are other patents for similar designs and most of them have some form of catch which would cause the plug to "click" into place. --Ziltro00:00, 9 November 2005 (UTC)
TT earthing
Re: "rv dubious edit by american who had obviously never heared of TT earthing" -- that would be me and I indeed hadn't. If I am not mistaken, TT earthing is not permitted under the U.S. National Electrical Code. However, the section in question, "The three contacts--earth" is written in a way that leads the reader to believe it is universal. No reference is made to it applying only to TT earthing systems. To the extent I understand it, the text as written is not correct when applied to the grounding systems (TN-S, TN-C-S) used in the U.S., among other places. This text needs to be fixed, particularly since it deals with matters of life safety. --agr
I think in its present form it adequately gets accorss both possiblilties. If you still have any specific problems with it go ahead and point them out. Plugwash23:12, 5 November 2005 (UTC)
It's been edited since I wrote the above and is better, but still, I think, confusing. I believe what needs to be made clear is that the "Earth" contact in a socket is connected to a third wire. That wire is then connected at some point either to neutral (TN) or actual earth (TT). Referring to this wire as simply "earth" is ambiguous. I also would like to see mention of the fact that in a TN system, a human connection between live and earth will not generally trip a circuit breaker even if a hazardous current flows, and that RCNs are advised/required in places where such an accidental connection is more likely, such as bathrooms, kitchens and other wet spaces. Finally, the RCN links need to be disambiguated. --agr23:36, 7 November 2005 (UTC)
BS 546
I have lived in England all my life and have been interested in electrical plugs and sockets for as long as I can remember.
There seems to be a lot of confusion about the old British standard BS 546, and I see a request for pin dimensions mentioned above.
BS 546 actually consisted of 5 different plug and socket combinations, not one of which would fit in to any of the others. All plugs were un-fused.
Here is a list of the types:
15 Amp 3 pin. (Still used in theatre lighting probably due to the large currents required and not wanting to have fuses in hard to access areas.)
5 Amp 3 pin (Still used in hotels, offices, houses, etc. for wall-swtched lighting.)
2 Amp 3 pin (Still used occasionally/rarely for wall-switched lighting, I have seen them in a person's home and in a pub)
5 Amp 2 pin (This is the standard the shaver plug came from.)
2 Amp 2 pin (Never seen these in use.)
I own at least one of each plug and socket excet for the 2 Amp 2 pin plug, which I have never even seen.
There are 4 dfferent sizes of pins used, I will call them 1, 2, 3 and 4 where 1 is the smallest.
All distances in mm. (although the standard is so old they were probably specified in inches; maybe someone who knows the inch system can work out what they could have been?)
There is a pattern to the use of the pins. Each type of plug uses 2 of the same size pins for Live & Neutral and the next size up for Earth.
The 2 pin plugs use the same Live & Neutral pins as the 3 pin version but are spaced further together.
Pin usage and distances:
2 Amp 3 pin:
Live & Neutral are Size 1. Earth is Size 2.
Distance between Live & Neutral: 14.60
5 Amp 3 pin:
Live & Neutral are Size 2. Earth is Size 3.
Distance between Live & Neutral: 19.00 (same as European plugs/sockets?!)
15 Amp 3 pin:
Live & Neutral are Size 3. Earth is Size 4.
Distance between Live & neutral: 25.40
2 Amp 2 Pin:
Both pins are Size 1.
Distance between pins: 12.70 (measured on socket as I have no plug)
5 Amp 2 pin:
Both pins are Size 2.
Distance between pins: 16.90
A Europlug will fit in to both the 2 and 3 pin 5 Amp sockets, however the 3 pin sockets have shutters.
These plugs and sockets were also used in British (ex)colonial countries. It seems that these countries have since chosen their current standard to be either the 15 Amp 3 pin, the 5 Amp 3 pin or have converted to BS 1363 like the UK did.
The British Shaver Plug may well have it's own standard now but it is the same size as the 2 Amp 2 pin BS 546.
Notes for travellers: If you see a round 3 pin socket in a hotel room it is BS 546 5 Amp 3 pin and is for lighting only. It will be controlled by to a switch next to the door and/or bed. If taking your shaver to a European country you might think the British Shaver Plug will fit in to their socket with no adapter, but it does not. It is possible to force it in, but don't expect to get it out again.
The 15 Amp 3 pin and 5 Amp 3 pin plugs/sockets are quite often confused when looking at photographs. It is impossible to tell which one is which because the photographs have no sizing reference.
I just found a good comparison of the hole sizes here: [7] —The preceding unsigned comment was added byZiltro (talk • contribs) .
The wiring colours for fixed wiring in the UK have changed, since 2006/04/01 red & black are no longer usable.
Info on new UK colours available here: Harmonised Cable Colours - The IEE
I was going to change the UK's entry to say "before 2006/04/01" and change the colours in that entry to only red & black, but the EU & Australia colours have red & black listed for live and neutral! This can't be true because black is an extra live in the EU colours.
Australia, as far as I know is still red & for fixed wiring, although they may allow brown & blue to be used?
Also, the colours for "plugs" are really for flexible wiring (including ceiling light fittings and wall heater flex) and the colours for "sockets" are really for fixed wiring.
Here is my proposed table, is it anywhere near correct?
AFAICT brown and blue fixed wiring is not even available in australia. I spoke with an electrical supply shop and he was of the opinion that only cords use brown/blue/green-yellow, fixed wiring is still all red/black/green-yellow by law.
Black wire is live in Croatia. As Standards here are alighed with German DIN, my guess was that black wire is live in EU as well. After reading above explanation, I am pretty certain about this. I marked word "black" with "?". If someone can confirm my view I propose to move black wire to live wires. Blue is only colour for neutral in Croatia. DarkoS17:59, 18 April 2006 (UTC)
Black is live in most of the EU, the UK (note: black is now used as a phase condutor in the UK but only on 3-phase installations) being the exception, i think brown is officially the preffered color for the live in single phase in europe (and its certainly what is used in appliance flex) but in many countries black is more common. Plugwash23:52, 19 June 2006 (UTC)
In the US, the live can be any color except white (neutral) or green (ground). Black and red are commonly used for single phase 120/240 systems, but blue is commonly used for the third phase in three phase systems. Blue and other colors are also used in single phase installations when multiple circuits share a conduit, etc. The screw colors are also applicable to the fixed cable section. --Rich02:55, 20 July 2006 (UTC)
I thought that, here in the US, we also excluded grey as valid color for non-neutral conductors. But I don't have a reference in front of me and could very well be mis-remembering this.
It is true that according to the NEC, grey represents a grounded (neutral) conductor. Typically, white is neutral on 120/240 or 208Y/120 systems, and grey is neutral on 480Y/277 systems, although there is much local variation.Yak9923:29, 22 April 2007 (UTC)yak99
I've got a draft copy of the 2008 NEC in PDF from the NFPA site. Section 200.7(C)(1) (page 70-33) confirms that. Ungrounded conductions shall be a color other than white, gray, or green. There is a note to be careful because, in the past, gray may have been used for ungrounded conductors. So you're right. --DragonHawk13:50, 20 July 2006 (UTC)
As pre-1969 wiring colours in the UK are listed in the table, it might be useful to add other old wiring colour codes. Although no longer in use for a long time, they obviously remain present in existing home installations for a century or so.
Perhaps it would be an option to split the table in "current colour codes" and "historical" or "old" codes, such a table might come in handy as reference when working on old installations. Codes I am familiar with mean nothing to a younger generation. Moreover, the "historical" table will be much larger than the current one.
A first addition : pre-1969 codes in The Netherlands (and likely other EU countries):
RED = neutral, GREEN = phase, GREY = ground, BLACK = switched phase (as today).
Pre-1969 codes in Belgium (where many different codes were in use, which may have differed per installer...): RED = ground, BLACK = phase, GREY = neutral. Further YELLOW and GREEN have been used for phase in BE.
Erik de Lange, AUG 31st 2006
active(hot)=brown;neutral=light blue;
ground=green/yellow;
For North American appliance cords:
active(hot)=black;
neutral=white;
ground=green. The international color code is also frequently found on appliance cords sold in North America. The link cited above should demonstrate the futility of creating a table of color codes predating international harmonization.
Yak9923:29, 22 April 2007 (UTC)yak99
image that came from the source this article was made from, VERY POOR
image in the article up until 17:11, 15 September 2006
nice image but the rather straight shot angle makes it a little difficult to see some of the defining features especially at smaller sizes.
2 French extension leads, added by ziltro, look pretty promising with a little work to extract one socket.
rotated and cropped version of ziltros image, now in the article. - Now removed and replaced with the next one Ziltro04:46, 8 December 2006 (UTC)
Better late than never... is this good ? - Even made by Legrand, how French! This looks much better so I have replaced the article's photo. Ziltro04:46, 8 December 2006 (UTC)
Because we don't have a GOOD picture. The one we have in the article now is low res and a powerstrip socket but at least shows all the essential features of the socket type reasonablly well. The image from the source this article was copied from (with permission) is absoloutely terrible. If you have a better image under a suitablly free license feel free to bring it up.
ok ziltro those powerstrips you added look quite promising, i'll see if i can get a good crop out of them sometime if someone else doesn't do it first. Plugwash13:16, 15 September 2006 (UTC)
Well, maybe a litte late (it's been months since I saw this article lacks a good picture of a french socket, and now you have one... ^^; ) but I uploaded a photo I just took of a french plug, feel free to use it :) If you want, I can try to take a better one ;) FF7Sephiroth13:55, 30 November 2006 (UTC)
The history of the self-dependent wiring
I tagged this section for cleanup. I think it is not well written and the implication that polarity doesn't matter in two wire circuits is not true in the U.S.--agr20:38, 16 April 2006 (UTC)
I agree with User:Plugwash that the section should just go. I've reproduced it below. A properly sourced history of which countries used two-wire, non-polarized systems and when they changed might belong here or in a separate article, but this section contains no specific historical info. Instead it seems to be trying to convey the author's opinion that in some ways thing were better in the old days when people could safely do their own wiring. (At least in the U.S., people still do.) That's an interesting argument, but as a personal point of view, it does not belong here. --agr02:21, 18 April 2006 (UTC)
Yeah you have to be pretty brutal with an article like this or you just end up in a flood of well intentioned but poor edits (either poorly written or taking the article offtopic). Plugwash12:54, 18 April 2006 (UTC)
The history of the self-dependent wiring
Some countries have used the two contact plugs and sockets in the past. There was no ground contact, and the live and neutral were treated fully equally. Despite such design is less safe in general, it is difficult to imagine how to make a wiring error, because there are only two wires, and swapping them is not a mistake. Any device was counted as energized as long, as the plug stays in the socket, and it was stritcly forbidden to replace the light bulb without disconnecting both wires with the main house power switch. The self dependent plug and socket replacement was widespread in such countries, being a kind of work that every self-respecting man should be able to do.
The modern installations are safer if done correctly, but the third (ground) contact opens possibilities for dangerous mistakes. Probably because of that reason it is now widely advised not to do wiring self dependently.
T-slot receptacles and their legality in Canada
(Speaking of confusing the Americans... :-) )
In the US, 20-amp receptacles commonly use a "T" slot on one side or the other, allowing the use of either a 15 Amp or 20 Amp plug. For at least some time, T-slots were banned by CSA in Canada. (I know this because Digital Equipment Corporation, my employer at the time spent a lot of money redesigning their AC power distribution systems to accommodate this CSA requirement.)
Now, though, it appears that T-slot receptacles are "OK" in Canada.
Can someone who actually knows the details add a brief history of all of this to the article?
Canadian electrical standards are being synchronized with American ones under the North American Free Trade Agreement (NAFTA). This means that anything approved by Underwriters Laboratories (UL) in the US is also approved in Canada, too. So, T-slot receptacles are now okay in Canada, as an alternative to the split-duplex receptacles that apparently frighten electricians in the US. I'd elaborate but I'm going to Peru for the next three weeks. RockyMtnGuy15:00, 10 May 2006 (UTC)
I've just removed the following, its probablly more detail than this article needs and it is contradicted by the post above, i have changed the html comments to bold text so they can be seen here.
In Canadian kitchens, it is mandatory to run a three-wire 240 volt cable to duplex NEMA 5-15 outlets and split the phases at the outlet, which is easily done by breaking off a metal tab on the outlet. This results in the duplex outlet being on two different 120 volt circuits (known as a split duplex outlet). Since the two live conductors are on opposite phases, the net current cannot exceed the capacity of the single neutral. The circuit is protected by a duplex circuit breaker supplying 240 volts on opposite phases, with a tie bar, so if one side trips, the other side trips, too. <!-- This has three hazards, however. 1) Modern electrical devices often have non-sinusoidal load currents, leading to incomplete cancelling of the neutral current and the subsequent overloading of the neutral. 2) If a future electrician moves the phase wires to other breakers but ends up with them on the same phase bar, the neutral will definitely smoke. 3) If the neutral line become open, excessive voltages can appear on the phase lines, and complete de-energization of the circuit requires opening both line breakers. Because of this, this sort of circuit is frowned upon in the US and *ONLY* permitted when the breakers are arranged for common trip. --> <!-- It may be frowned upon in the US but it is *MANDATORY* in Canadian kitchens. They just do it to confuse Americans. The thing I didn't mention is that they can be rewired for European 240 volt appliances. -->
Not in the US (AFAIK), so long as you meet the constraint of using a two-pole breaker or tying the handles of two single-pole breakers. But my comments about high-neutral currents for non-sinusoidal loads still apply.
The "high-neutral" currents will never exceed 15 amps, so there's no problem in sharing it between the two hot conductors. This has been used in Canada for decades. However, the 20 amp T-slop receptacles used in the US were prohibited by Canadian authorities because they thought they were dangerous. However, neither method killed that many people, so either one can be used in Canada now.
Speaking of killing people, you should see the outlets in Peru. They accept 220V Europlugs and American 110V Type A plugs, they're unpolarized and ungrounded, and they may be 240 volts by 30 amps! And they put them in bathrooms! Woo woo! But the electricity is safer than the water... RockyMtnGuy18:52, 28 August 2006 (UTC)
Actually on most newer Peruvian socket, the "American" part of the receptacle hole is polarized, if you look carefully (I have a powerstrip with such sockets in my collection of wiring devices and it accomodates polarized plugs just fine). Assume that a Peruvian socket is 220 volts, no matter what the shape of the plug; whether "American" or "European".Stephanie Weil19:43, 15 March 2007 (UTC)
Unfortunately, here in the days of non-sinusoidal load currents, it actually is possible to develop more than 15 (or 20) amps RMS on the neutral sitting between two 15 (or 20) amp phase conductors. The problem occurs when each phase is drawing a substantial pulse of current somewhere along the sine wave cycle but the pulses from each phase are not synchronized in time. This also occurs when the two phases have loads that produce different (so non-cancelling) harmonic spectra. In these modes of operation, the neutral can cook. It is partly for this reason that various regulatory agencies are starting to get up-in-arms about non-sinusoidal load currents, harmonics, etc.
I realize that if you have a building full of 3000 hp electric motors that strange things can happen, but the Canadian electrical code has a lot of restrictive rules that limit the potential for weird harmonics in household power. The idea in kitchens was to get away from nuisance circuit breaker tripping due to multiple appliances on the same circuit, and either split-duplex 240 volt 15 amp or single phase 120 volt 20 amp will do that. Now, ideally, they would use single-phase 240 volts, but that's not an option in North American homes. RockyMtnGuy21:28, 28 August 2006 (UTC)
3,000 HP motors aren't the problem; nowadays, they have fancy controls that allow them to draw sinusoidal current. The problem is much more the cheap electronic power supplies that are found in computers, many modern microwave ovens, fluorescent lampballasts, and the like. These are the loads that cause weird current flow in the neutral wire.
I don't know, buildings full of 3000 hp electric motors seemed fairly problematic to me. I used to install computers in gas plants, and the plant motors could induce 200-volt surges in the network wiring, nevermind what they did to the commercial power (dim the lights for 50 miles around when the plant started up). The only solution was fiber optics and running the computers on a good UPS. Canadian electrical code requires putting microwaves on their own separate circuit. RockyMtnGuy02:31, 29 August 2006 (UTC)
Really? 26-720 only requires a separate branch circuit for a microwave oven plug only if it's installed in a cupboard; sounds like this has nothing to do with power quality. --Wtshymanski18:22, 30 August 2006 (UTC)
Well, on actually reading the code, if it's not a built-in microwave you could just plug it into a kitchen counter outlet. (Both my microwave manual and my friendly local government just said "a microwave should be on a separate circuit") And I don't think it makes much difference as long as you don't plug a stereo into the same outlet. I'm just having trouble with the idea of one of the phases on a split duplex circuit getting more that 90 degrees out of sync with the opposing phase, which is what it would take to overload the shared neutral. RockyMtnGuy03:50, 31 August 2006 (UTC)
thats because you are thinking in terms of magnitude and phase and not considering harmonics. Harmonic currents are nasty because they don't represent any net power transfer and they can't cancel with anything except other harmonics of the same freqency and even then the phase of the harmonics must be right for canceling (e.g. 3rd harmonics in three phase systems basically don't cancel at all). Having said that i think in domestic use with half decent power supply filtering the issue isn't too series. Plugwash11:07, 16 September 2006 (UTC)
Italian/Swiss plugs in Spain?
I'm assuming that what you thought was an Italian socket with the third hole was just a regular two-pin socket. The "hole" in the middle probably is where a mounting screw is supposed to fit - probably what holds the base and the housing together? I've seen some sockets like that. StephanieNYC 13:36 24 May, 2006 (EDT)
I´ve moved into an apartment here in Spain where all the earthed sockets are of a three-pin type, but like the Swiss rather than the Italian type. I can´t find any corresponding three-pin plugs locally to fit them and don´t have any Swiss plugs to hand! The only possible mention of them I can find anywhere is the following line that was under ´Type J (Swiss 3-pin)´, but for some reason has subsequently been deleted:
This type of socket also be sporadically encountered in buildings in Spain, where they may be erroneously referred to as enchufes americanos — American sockets.
Btw, the building dates from 1981 so is relatively new! If I don´t find plugs to fit them, I´ll have to replace them all for safety´s sake..
110v vs 220v
Is there someplace (or someone) that can tell me why the US & some other countries use 110 while most of the world uses 220? Are there advantages/disadvanteges to either one? -- UKPhoenix7911:25, 3 June 2006 (UTC)
I'm sure I've seen this described somewhere on the Wikipedia (thought it might be at List of countries with mains power plugs, voltages and frequencies but it's not). Voltages near 100 Volts make for more rugged and longer-lasting incandescent lamps, at least with the technology of the late 19th century. There was also a feeling at that time that 100 Volts was a safe ptential to touch (Lord Kelvin evidently thought so), but our ancestors must have been hardier and we don't think that it's a particularly safe voltage. The advantage of voltages near 200 V is that for large-ish loads you need smaller wires for a given quantity of power. The advantages of one voltage over another have not compelled anyone to switch. One advantage of a 240/415 V three-phase system is that you can tap single-phase lighting circuits off the same panelboard that feeds 3-phase motors without the need of lighting transformers; for example in Canada we'd run lighting off a 600 V to 120-208 V small transformer. No doubt if someone did a complete economic analysis they'd find the absolute optimum system was 173 V at 33 1/3rd Hz but no-one would convert now. --Wtshymanski19:32, 3 June 2006 (UTC)
"The advantages of one voltage over another have not compelled anyone to switch." does any country still use 120V single voltage in new homes? I'm pretty sure most such countries are now using dual voltage systems with 120V for small appliances and lighting and 240V for anything that actually uses significant power. Plugwash21:57, 3 June 2006 (UTC)
The use of 110 volts in the U.S. is primarily due to Thomas Edison, who invented the light bulb but insisted on using no more than 100 volts DC. It was Westinghouse who introduced AC. Tesla calculated that 240 volts 60 Hz AC was optimum, but cautious regulators limited Westinghouse to 110-125 V. Later, they came around to Tesla's point of view, but by then North America had too many 100-110 volt appliances to switch. They compromised with today's system - which is actually split-phase 240 volts. It is 120 volts phase-to-ground and 240 volts phase-to-phase. They use the safer 120 volts for lighting and small appliance outlets and the more efficient 240 volts for electric stoves, clothes dryers and arc welders. RockyMtnGuy21:11, 28 August 2006 (UTC)
So what voltage/frequency (out of the whole range, from 0 to stupidly large) *is* optimum?
Perhaps a better question is: What sorts of things would one include in such an economic analysis?
I've thought about this a bit, and here are a few considerations:
lamp lifetime: Yes, 100 V gives "more rugged and longer-lasting incandescent lamps" compared to 240 V, but 12 V would be even better. (Most of the long-lasting halogen light bulbs I've seen run on 12 V).
The only voltage vs. lifetime effects I know of is the opposite. Below about ten volts, one must use special gas inside the envelope to make the lifetime practical. For example, 12 volt flashlight bulbs have an average lifetime of about 1000 hours. 1.5 Volt flashlight bulbs have an average lifetime of about 10 hours. Main reason being is that the manufacturer does not add the noble gas to the latter in order to save money. A referral to 1950's era bulb spec's for the latter bulbs reflect this, giving lifetimes of about 1000-2000 hours. Another effect is current. Higher currents tend to 'deplete' the filament near the negative end, weakening it over time. Studies have shown that in high reliability applications (such as vacuum tubes), DC filaments tend to fail at the negative end when driven by DC current, and higher current causes higher failure rate. So one could conclude that higher voltage lamps, which require less current for the same light output, would last longer.
I suspect there is a breakpoint somewhere between different affects, as the voltage increases and i'd imagine the affects that are most important in a comparison of say 6V vs 12V would be very different that those in a comparison between 120V and 240V. Beyond a certain voltage the filament is going to get very thin, that means more prone to mechanical damage. Plugwash21:38, 9 February 2007 (UTC)
safety: In general, lower voltages are safer; however High voltage mentions that "On the other hand, voltages above approximately 500 V have a natural defibrillating effect, so sometimes a higher voltage can be safer than a lower voltage, though by no means safe. A DC circuit may be especially dangerous because it will cause muscles to lock around the wire."
I've heard rumors that some military aircraft use 400 Hz, because for the same power rating, a transformer designed to run at 400 Hz weighs much less than one designed for 60 Hz. Most switched-mode power supply run much higher frequencies, because higher frequency allows them to use smaller and lower-cost inductors and capacitors for the same power rating).
As a general rule higher frequency means cheaper/lighter but less efficient, very low frequencies also have other problems such as light flicker.
acoustic noise: electronic equipment *seems* much quieter if it runs off frequencies outside the human range of hearing (20 Hz to 20 000 Hz). Most switched-mode power supply run at over 20 000 Hz, so humans can't hear the noise they make.
I can well belive that, but missing at the bottom end would cause percivable lamp flicker and missing at the top end would cause much lower efficiancies. Plugwash21:38, 9 February 2007 (UTC)
wiring cost: The higher the voltage, the less metal is required for the power cables. (But for domestic flexible power cords, the thicker plastic is required for insulation).
efficiency / energy loss cost: The higher the voltage, the less energy is lost in the transmission lines (until you get high enough to get corona discharge).
IIRC higher frequencies bring lower weight but higher losses so they are mostly popular in mobile stuff (aviation, military etc). Generally higher voltages are considered more dangerous (i don't think i've ever seen that defribrilating effect mentioned outside wikipedia and i would therefore take it with a grain of salt).
A few comments about this:
In North American, George Westinghouse's early generators produced 133 Hz, but when Nicola Tesla invented the polyphase electric motor, he designed it to run at 60 Hz. Tesla's electric motor wouldn't run at all at 133 Hz, so Westinghouse had to reduce the frequency of his generators to match, because Tesla owned all the patents.
Historically, a wide variety of frequencies were used, from 25 Hz to 133 Hz. It mostly depended on how fast the generators rotated. A four-pole generator turning at 1800 rpm would produce 60 Hz electricity.
If the frequency was much lower than 50 Hz, some people would be able to see the lights flicker. That defines the lower limit commonly used.
The higher the frequency, the smaller the transformers required. 60 Hz requires somewhat smaller transformers than 50 Hz. 400 Hz permits very small transformers, but you can't transmit 400 Hz very far, which is why it is used in aircraft.
Locomotives don't care much about frequency. DC is often used. North American railroads mostly use variable-frequency AC on their diesel-electric trains.
The higher the voltage, the smaller the wire that is required to transmit the same amount of power. 240 V requires half the amount of copper as 120 volts, which is why it is used for heavy appliances even in North America.
Higher voltage increases the risk of electrocution, which is why it is limited to 240 volts in households. Industrial equipment runs at 400 to over 4000 volts.
I don't think I'd trust the "natural defibrillating" effect. There are a few more useful tricks. One is, after you shut the power off and open up an electrical box, hold a screwdriver by the insulated handle and touch the blade across the live, neutral and ground wires. If the breaker wasn't really off before you do this, it certainly will be afterward. And, the first time you actually touch a wire, touch it with the back of your hand rather than the front. If it's really live, your hand will jerk away from the wire rather, than toward it. RockyMtnGuy00:48, 31 October 2006 (UTC)
I found the reason that some locomotives used 16.7 Hz. See 15 kV AC. The choice is because of technical limitations at the turn of the last century. At higher frequencies they had commutator arcing problems with the electric motors. Most of these systems have been converted to 25 kV, 50 Hz a.c., Overhead Line because it avoids having to have a separate 16.7 Hz power grid, and the higher voltage is more efficient. Some railways in desert areas use 50 kV because it is even more efficient over long distances. RockyMtnGuy20:21, 31 October 2006 (UTC)
The major reason for 16 Hz to 20 Hz Locomotives goes back to turn of the century limitations. The earliest use of Electricity was lighting, and motors. DC motors came first, with AC motors being invented by Telsa. AC won out because of the advantages in distributing it. But the operators of heavy DC Motors had a problem. DC Motors produced much more torque. So DC motors continued to be used for such things as Industrial, Elevators, and trolley cars. Problem was, you either had to build your own DC power plant, or convert the AC to DC at high current. Unfortunately, the only practical way to convert AC to DC at the time with any kind of current capability was to use mechanical switches. Their mass prevented them from operating much above 20 Hz, so heavy equipment such as Industrial motors, Trolleys and Elevators got their own distribution network, giving then the advantages of DC Motors with the ease of AC power distribution. Early Radios reflect this by having two types of AC power supply, 20 Hz and 60 Hz. When Electric Locomotives came along in the late Thirties, the Engineers simply used the electric motor standards and equipment in their field, i.e. 16-20 Hz.
No it won't fit. The pins in the new Israeli socket are spaced exactly as the old one, meaning the ground pin is much more off center than in the Swiss plug.
194.90.21.7410:26, 19 July 2006 (UTC)
The NEMA 2 connectors are basically obsolete 240V devices that you're not likely to see in a household (or anywhere else). That section could be usefully be removed from this article. Missing are the NEMA 14 connectors. The NEMA 14-30 plug is now standard for electric clothes dryers, the NEMA 14-50 plug is standard for electric stoves. RockyMtnGuy01:03, 9 September 2006 (UTC)
Do sockets really exist that can take both Schuko plugs and the 16A variant of CEI 23-16/VII? I wouldn't have thought such plugs would have fitted in the cavity even if the needed holes were there.
Yes, I've seen such combo sockets in Italy. The cavity of these sockets is indeed wider than the cavity of normal Schuko sockets. 194.90.21.7406:36, 4 October 2006 (UTC)
Yeah, they exist. But the 16A variant won't (always) fit in a Schuko cavity like this, it needs an enlargement of the cavity. I'll post pictures of a 10A/16A/E/F socket as soon as I can. Danilo Roascio11:37, 22 June 2007 (UTC)
Article Cleanup
This article is currently going a cleanup to ensure it meets Wikipedia standards. There are some issues involved with this.
Terminology
There are significant differences between British English and American English in this area. There are 60 million people in the United Kingdom versus 300 million in the United States (and 33 million in Canada). The Americans are generally unfamiliar with British English so it's important to translate it for them. Keep the English simple and use terminology that laymen can understand.
Earth is known as ground in American English.
Flex is known as cord' in American English
Trouble is, in English 'cord' means rope, which has no links to electricity at all. I assume 'flex' has a similar lact of link with electricity in American English? How about 'flexible cable' instead? Or maybe 'lead' depending on where it is used? Ziltro19:32, 2 October 2006 (UTC)
"Appliance power cable" might be universal. Long and tedious, but universal.
The trouble with flex is that, according to the Random House Unabridged Dictionary it is British: Any flexible, insulated electric cord; an electric cord or extension cord. Wiktionary says, (mostly British) insulated electrical wiring. I noted in my reading that the Australians seem to use cord. To be safe, you'd have to say flexible electric appliance cable. RockyMtnGuy23:12, 2 October 2006 (UTC)
RCD in Britain is GFI in America. And GFI sockets cost about $7.00 apiece in the U.S. so they're used everywhere.
Also known as RCD in Australia. Google search for "Residual Current Device" returns 5,010,000 hits, search for "Ground Fault Circuit Interrupter" returns 278,000 hits. Wikipedia even has an article called "Residual Current Device". Ziltro19:32, 2 October 2006 (UTC)
The article also notes that it is more accurately called a balance fault interrupter or BFI. Unfortunately, hardly anybody uses that term. RockyMtnGuy23:12, 2 October 2006 (UTC)
TN vs TT grounding is too technical for most readers (and is covered in another article on earthing.)
Yes its technical but insisting there must be a low impedance path back to the transformer neutral when that simply isn't the way its done in much of the world is very misleading. To explain earthing at all and keep a worldwide sense you have to explain that there are two basic options (get the EFLI very low or use a RCD). Earth=ground was already mentioned not sure about flex VS cord. Plugwash15:43, 21 September 2006 (UTC)
I didn't say anything about a low impedence path back to the transformer neutral. What I said (in an attempt to keep it nontechnical) was, It is intended to provide a very low resistance path back to the source of the power so that in the event of a fault, enough current will flow to cause a breaker or fuse to open and automatically disconnect the faulty equipment.... If it was modified to say "...earth, or source of the power.." and "...an RCD, breaker or fuse...", you would have other earthing systems covered.
The acronyms TT and TN are not commonly understood or used in North America because, if you only have only one system, you don't have to distinguish it from anything else. (I think it would be called TN-C-S if I understand what I am reading.)
People in Britain have to realize that, while they understand the American dialect because they hear it all the time in the movies and on TV, Americans do not hear everyday British English very often, and it tends to baffle them. (In Canada, we are confused and use British and American words interchangeably without knowing which is which, but in the area of electricity we use American terminology and technology almost exclusively.) RockyMtnGuy21:33, 21 September 2006 (UTC)
but "It is intended to provide a very low resistance path back to the source of the power" is essentially a less technical way of saying "low impedance path back to the transformer neutral". Either way it is plain wrong in the case of a TT installation! Plugwash01:47, 22 September 2006 (UTC)
And that is why I suggested adding a couple of extra words to the non-technical explanation to cover the TT case, rather than converting the explanation into technical language. Some of this technical jargon will confuse many readers who are only concerned about how their simple power plugs work. RockyMtnGuy22:39, 26 September 2006 (UTC)
I don't know about the technicalities of different earthing types, but I thought the idea of having an earth connection is that it is connected to the chasis of a metal device and if the live wire comes in contact with the chasis then rather than energising the chasis it will cause a short circuit which will melt a fuse or trip a circuit breaker. Does the article really need to go into any more depth than that? I also don't know what you mean by "the transformer", the one at the local substation? Surely the electricity goes all the way back to the power station? ;) Ziltro19:32, 2 October 2006 (UTC)
That is essentially correct. The above-mentioned RCD is actually a form of circuit breaker that trips on a current imbalance rather than an overload situation. I was trying to get phrases like residual current device, low impedence path and transformer neutral out of the article because many people don't really understand them. The transformer Plugwash is talking about is located close to your house and steps the high voltage down to 120/240 volts for delivery to you and a few of your closest neighbors. Many people don't know where it is, and don't need to know about it to understand how a plug works. RockyMtnGuy23:12, 2 October 2006 (UTC)
Turgid Prose
It's important to avoid circumlocutions and convoluted sentences (and words like turgid, circumlocution, and convolution). The English must be kept simple and straightforward for the benefit of the readers.
References
This article needs more references. Hunt them down and put them in.
Where an article has both references and footnotes (and I'm adding footnotes now). The Wikipedia standard is to have one section for References and another for Notes. Let's stick to that.
Length
This article is basically too long. It's difficult to condense it, given the number of incompatible standards it's dealing with, but try to keep the text short and pull any lengthy sections off into their own article, with a short summary here and a link to the sub-article.
The Europlug deserves its own article (and, I believe, has one).
The American Type B plug probably has enough variations to deserve its own article.
Would it be better to have some sort of indication of scale on the various pictures otherwise some of the different ratings of plug can look very similar. A ruler in the picture is the easiest way.
Yeah, there are two issues though, firstly this article is already pretty chock full images wise (pretty unavoidable given that a photo of both plug and socket of each type really is desirable info). so adding scales to images would mean either making the actual pictures of the plugs smaller or the images as a whole even more dominant. Secondly unless someone here has both a good camera (and the skills to use it) and a big collection of plugs re-doing this articles photo selection would be a big big job. Plugwash19:57, 28 September 2006 (UTC)
I have a collection of a lot of plugs & sockets and a good camera. I have "properish" wall sockets for: USA 2 & 3 pin, France, BS 1363 (I'm in the UK so loads of these), every socket in BS 546, Australian 10A, 15A and 10A with a round earth pin. I want to do a group shot of all the sockets so they can be compared visually but feel that I have a lot missing. So if somebody could send me sockets (and plugs!) for types F, H, J, K and L suitable to be mounted on a piece of wood then I'll photograph them. ;) I have photographed my collection a few times (some are even on Wikipedia) but I haven't felt they are good enough to replace anything on here. One problem is the dark bakelite ones, here for example, brown bakelite is hard enough to photograph but next to white plastic? That took a while! And it's still not as good as I would like. Ziltro18:30, 2 October 2006 (UTC)
Domestic power plugs
What do people think of this one? We've said that a lack of inline citations will override keeps, and this only has a 11 plus the comment "The original content for this article came from http://users.pandora.be/worldstandards/electricity.htm." But then, there is a large number of different links, so the info can be easily checked. Marskell19:41, 30 September 2006 (UTC)
Type E (French 2-pin, female earth) - live / neutral connection
Recently there were changes to the Domestic AC power plugs and sockets#Type E (French 2-pin, female earth) regarding the connection of the live and neutral lines. User:195.162.202.45 inserted statement that the socket is installed with live wired to the right hole. He/she supports the edit by the following statement: Looking into the socket, in correspondence with BS 546, cut any IEC C13 CEBEC/VDE computer cord.
I cannot agree. In the Czech Republic these sockets are installed with live wired to the left hole. Unfortunately I do not know the standards (IEC 60083) but I think that the position of the live and neutral is probably not specified by the international standards.
I hope I will find time to go to the library and to study: IEC 60083, ČSN IEC 60884-1 (+ Opr.1), ČSN 35 4516, ČSN IEC 60083, Věstník ÚNMZ 2004/12 (revoking ČSN IEC 60083).
I have a few French plugs & sockets and I don't remember ever seeing any markings on them showing where live and neutral go. Earth was marked, but nothing else. I suppose it doesn't really matter, especially as they don't generally use switched sockets. I don't think there is a standard, but I have no way or proving either way! Ziltro18:56, 23 October 2006 (UTC)
After reading this comment I checked 5 power cords and a detachable IEC C13
line socket. This C13 is marked N-E-L when looking into the socket with
the earth hole upwards. The moulded CEE 7/7 plug to IEC C13 socket cables
are wired as follows:
1. Hitachi Hirakawa-FP Japan VDE/CEBEC: C13 markings N-E-L, earth hole
upwards, live is wired to the right hole of a mains type E socket,
After a search I found two moulded plug counterexamples, both unterminated:
4. A pre-1989 cable which came from a Nilfisk vacuum cleaner: brown=left hole,
5. Brennenstuhl 1-17205-4 h07rn-f 450/750 V 3G 2.5mm^2: brown=left hole.
So, it indeed seems that there are two customary practices. I have once
received a leaflet describing recommended socket wiring for renewed 3P+N
installations and will report it here if I come across it. User:195.162.202.45 29 Oct 2006.
To follow up: I found a straight CEE 7/7 plug model
K 616 / 8X 1-31 / CEBEC / VDE in black bakelite-like plastic
probably dating from 2002. It has markings on the inside which define
the socket holes, with the earth pin upwards, as follows: left is live
and right is neutral. The white variant of this plug sells under the Lucas
brand, model P220W, part number 43.616.8, EAN 54.11408.00220.9.
195.162.202.4500:44, 30 October 2006 (UTC)
In France, the common practice is to wire the live on the right (facing the socket and earth upwards. — I learned this during my electrical engineering course ("BEP Électrotechnique"), and during my trainig period with an electrician), but this is not mandatory. FF7Sephiroth10:20, 30 November 2006 (UTC)
In Czech republic is live on the left, neutral on the right and earth upwards (Max)
In France, although the plug cannot be physically reversed in the socket, there is no defined polarization of the socket. Indeed most double outlets and two way adapters have the two sockets hardwired internally the opposite way around. A few areas of France have both main supply conductors 'live' as neither are at or near earth potential, so it isn't possible to define either conductor as a neutral. —Preceding unsigned comment added by 81.187.162.109 (talk) 11:49, 13 October 2007 (UTC)
U.S. Type A power plug
Wonder what the hole in the flat pin is for? Type A jacks use the spring action of the leaf contacts in the socket to make good contact. Early metalurgy was not that reliable, the spring action weakening over time. So instead, contacts in the socket had a small metal ball held in place by a regular coiled spring. When the plug was inserted, the ball would drop into the hole in the pin. Metalurgy has improved, and the ball is no longer needed, but the artifact remains. —Preceding unsigned comment added by 151.199.25.48 (talk • contribs)
That is one of about two or three explanations i have seen for the feature, so this will need a REALLY strong cite before i will even consider adding it to the article. Plugwash21:48, 19 November 2006 (UTC)
Well, the hole is handy for clipping your test probes into, and if you want to lock-out a device, you can pass a small padlock through it [:-) / 2]. But it's clear that the hole isn't really required for anything as certain plugs (usually on cheap imported devices) have just solid prongs with neither spring contacts nor the hole.
The holes are so that the socket can clip on to the plug. I don't know why modern USA sockets don't seem to have this, they really could do with it! Maybe that's only a theory, but it is shown on the page in the US patent image, parts 35 and 29. I even found similar things in other US plug/socket patent drawings when looking for the currently used one. (Which I never found - anyone know it's US patent number?) Ziltro16:39, 21 November 2006 (UTC)
I'd actually bet that the holes were useful in the past, but are now obsoleted by the materials and surface treatments chosen for the socket contacts and plug prongs. But I have no citation to back this up.
According to NEMA, the holes are optional and are for manufacturing purposes only. However, if they are present they must be of the exact specified dimensions. Some people claim that they are used during manufacturing to hold the blades in place while they mold the plug. As to the other claimed purposes (for bumps in contact slides to fit into, for a locking pin, for attaching a tag saying "Do this before plugging it in, or you will die!") - they may all be true. Once you put a feature in a standard, and don't explain why, you can never get rid of it because people will use it for things you didn't intend. RockyMtnGuy21:01, 21 November 2006 (UTC)
Unique Safety feature of Schuko sockets
One feature I cannot find mentioned is that the German Schuko sockets have a special safety feature: The socket's cavity avoids the possibily of being able to touch the "hot" line while inserting the plug into it because its pins won't touch the socket's connectors until the the plug's casing has enclosed (and sealed) the socket's "hole". Contrary to this, most other sockets would allow to stick a small (children's) finger or other conductor between plug and socket and get an electrical shock.
-- Tempel09:18, 21 November 2006 (UTC)
Modern BS 1363 plugs also are safe in this way. Because the BS 1363 prongs only have a conductive portion at the tip of the live and return prongs (with the rest of the prong lengths being plastic-coated), the conductive portion of these prongs are well-inside the socket holes before they contact the socket's conductors. Many (all?) Europlugs are also built this way. Mostly it's just the plugs designed on the American pattern (with very slender blades that aren't conducive to partial insulation) that can still zap you on insertion.
Its a problem that most first world countries that use 230V (or thereabouts) as thier main domestic voltage have solved in one of two ways. Schuko french danish and swiss plugs use the cavity system while british italian australian and europlugs use the partially insulated pins system. The americans don't seem to have bothered possiblly because thier lower voltage lowers the risk. Plugwash13:47, 21 November 2006 (UTC)
American voltage is only half as much as European voltage, and the American plug design makes it difficult to hold the plug close to the contacts. The grippable part is usually at least 25 mm away from the contacts, or has an insulated rim between it and the contacts. Also, American standards require any socket in a potentially wet area or close to plumbing fixtures be a Ground Fault Circuit Interrupter (GFCI) design, which will trip on a 6 mA current imbalance (i.e. much less than is required to electrocute anyone.) RockyMtnGuy15:52, 22 November 2006 (UTC)
In my experience the american plug is very easy to touch the live contacts, if you pull it out and down at an angle there is a lot of live metal exposed. I am assuming (hoping?) that this apparent lack of concern for safety is because of the low voltage, but I wouldn't want to bet my life on testing it! The main reason for plastic shielding on Aussie plugs (from what I read somewhere) is because of the possibility of sliding a sheet of metal between the plug and the socket. It is impossible to touch the live pins because of the size/shape of the plug. I believe the Europlug has plastic pin tops by definition, otherwise it is not a Europlug. Ziltro18:33, 23 November 2006 (UTC)
I to think that it is easy to touch the live contacts on an American plug, as many times I have attempted to plug something in complete darkness, guiding the blades with my fingers feeling for the outlet... Foolish I know. However, generally most users touching one contact are ungrounded, so they would become just an extension of the circuit if it became energized while a finger was still on it. Partially insulated blades are a great safety control, but require plugs to be (generally) larger. JAK8304:42, 5 February 2007 (UTC)
Could this be somehow discussed in the main article? I mean the facts. If the cavities for Schuko and E type sockets and the insulation on the plug pins were designed for safety it should be mentioned. And it would be great if it could be mentioned why the US system does not use it (low voltage is safer, was considered but too expensive, or whatever). (BTW I touched the pins in US twice, both time I was lucky it was a GFCI sockets). Also shouldn't the article say that some countries use GFCI in the socket (US), some use the "fourth" wire (Europe). I am no expert so I cannot do these changes, sorry. --Jirka605:24, 29 August 2007 (UTC)
illegality of cheater plugs
Firstly what does most places reffer to? if its just most places in the US and canada then that should be mentioned explicitly.
Secondly what exactly is illegal? making cheater plugs? posessing cheater plugs? selling cheater plugs? using cheater plugs? Plugwash01:16, 23 November 2006 (UTC)
Most places means "more than 50% of places". And by that I mean more than 50% of places using Type B plugs.
Remember, Canada, the US, and Mexico are federal states, not unitary states like England, and electrical standards are set at the state/province and local level. The U.S. National Electrical Code and Canadian Electrical Code are just guidelines, and each state and province sets their own regulations. The Mexican electrical code is just a Spanish translation of the US NEC. Any state or province can make these things illegal within its jurisdiction, and most (or all) do. How they make them illegal is up to them. Some can be quite creative about drafting laws.
In general, national governments don't make selling these things illegal in case some state/provincial government wants to make them using them legal under some circumstances. And there are legitimate uses for them, other than circumventing the electrical codes. For more details, just get yourself a huge pile of lawbooks and start reading. RockyMtnGuy15:40, 23 November 2006 (UTC)
This describes the situation in the US, where the NEC is written by a consortium of interested industries and adopted at will by states and municipalities. If there is any local area which has not adopted the NEC (and surely there must be a few), the contractor would have to contemplate having to explain in a court of law why the generally accepted standard of electrical safety was not followed. Therefore, the NEC is the de facto standard throughout the US, although it does not have the force of Federal law (except for installations on Federal property). I cannot speak to the Mexican situation; I too have heard that the Mexican electrical code is a verbatim translation of the US NEC, but I cannot verify that. FWIW, my travels in Mexico tell me that if this is the case, it is not very well enforced. I have heard the situation is different in Canada: if a specific device is not certified by CSA, it cannot be sold. This situation does not exist in the US. Yak9923:58, 22 April 2007 (UTC)yak99
What I don't understand about these is why anyone would bother with them, surely if you have a two pin socket then it can be reasonably assumed that there is no earth connection on it at all. And if there is an earth connection, why install a two pin socket? In Florida I bought a two pin socket (standard "duplex" type) and it was more expensive than the three pin equivalent. So use of these devices is pretty much guaranteed to be dangerous in that there is no earth connection where one is required. How many places still have two pin sockets anyway? I never saw any in use. Ziltro17:34, 23 November 2006 (UTC)
The two-pin sockets are more expensive because they sell a lot more of the three-pin ones. Two pin sockets were prohibited for new construction in 1960, but a lot of older homes that haven't been rewired still have them. And, since a lot of equipment comes with three-pin plugs, people living in these houses buy these cheater plugs or break the ground pin off, both of which are dangerous. If the device didn't actually need a ground connection, it would have a two-pin plug. The accepted method of fixing these sockets per the NEC is 1) running a ground wire to it, or 2) using a ground-fault interrupter socket and labelling it as ungrounded. Both are legal (in most jurisdictions, per the discussion above).
There's another issue involving audio equipment. Ground loops can put a hum or buzz on the wires. Some people use a cheater plug to disconnect the ground to get rid of the hum. This is still dangerous, so you should use a ground loop isolator or buy equipment with a ground lift switch on it. Presumably if the equipment has a ground lift switch, it is safe to use it. But, at the end of the day, the real problem is with people that are too cheap or ignorant to do things properly and safely RockyMtnGuy22:22, 24 November 2006 (UTC)
People persist in questioning that these things are illegal. I added a reference that shows they are illegal for sale or use in Canada. Cheater plugs are still sold (possibly even legally) in the U.S., but using them would violate the National Electrical Code, which requires a functioning equipment ground, and a lot of jurisdictions have prohibited them under health and safety regulations. These things have killed a lot of people, particularly musicians who use them to eliminate the ground noise on their equipment, but apparently a lot of people think they can make an intrinsically dangerous electrical installation safe somehow. RockyMtnGuy16:28, 9 December 2006 (UTC)
My understanding of "cheater plugs" is that they're to be used when the outlet itself is ungrounded, but a ground can be arranged through other means -- thus the tab sticking out. A common application I've seen suggested is to connect that grounding tab to the casing of the outlet, I think because the idea is that the casing is grounded via the conduit (assuming metal conduit.) kmccoy(talk)14:19, 5 February 2007 (UTC)
You're exactly right. You cannot assume that there is no ground at a two-pin receptacle, especially if it's on metal conduit or flexible armored cable. The house I grew up in was built in 1959. and the code at that time and place (Eastern Oregon) required metal junction boxes to be grounded, but did not yet require receptacles that would accommodate a grounding pin. In such cases, a "cheater" if properly connected to a metal screw would in fact be a safe installation. ---RDV 26 Feb, 2007
In theory it would be a safe installation. In reality, that green tab is so thin it is easily broken when the appliance is unplugged. Any person capable of verifying a ground is probably also capable of replacing the receptacle. Yak9923:43, 22 April 2007 (UTC)yak99
Diagrams
I don't know if these could be of any use. I have created some diagrams using the measured sizes of plugs & sockets I have here. They aren't the official sizes but they are close. They are all shown in an 80mm box to help with size comparison. All diameters taken from the pins, but diagrams are looking towards the sockets. I have entered the dimensions in to the SVG files because I wanted them to be 'correct' rather than using pixel sizes which might look ok but wouldn't actually describe anything. (Also if you print them they should come out actual size.) I don't seem to be able to make the AS3112 (Australian) one due to the 30º angle rotating the angle of the X and Y coordinates as well as the object! I will have to have another go at it some time. SVG does seem to be lacking in the idea of user settable origins, circles are centre/centre and rectangles are top/left which makes the sizes in the SVG files look a bit odd. I should be able to make the Schuko socket soon. Ziltro05:10, 8 December 2006 (UTC)
Not bad but i think we'll wait until the complete set is done before putting them in the article, also we will probablly have to push some photos out when we add them as the article is already image heavy. Plugwash21:29, 9 February 2007 (UTC)
Consolidate and standardize terms used
Specifically, the terms 'plug' 'socket' 'outlet' 'receptacle' and 'connector' are used frequently in the article, sometimes incorrectly or in place of a more preferable term.
'Plug' generally refers to the male end of an electric cord, but can also refer to the female end of the same cord. (In North America)
Same in the UK, some people call a socket a plug. I have never worked out why. But 'plug' is the best description of the male connector. Of course because 'cord' means 'cordon' ie. rope, so isn't used in the UK to describe an electrical cable. Ziltro17:36, 5 February 2007 (UTC)
'Socket' generally refers to the female part of a lighting fixture, used with some sort of light bulb. (In North America)
I think this is refered to as a 'bulb holder' or 'light fitting' in the UK. I don't ever remember hearing one refered to as a 'socket'. Ziltro17:36, 5 February 2007 (UTC)
'Outlet' generally refers to a typical wall mounted electric source, that is used to 'plug' in appliances and lighting fixtures. (In North America...)
Yeah, I suppose there is no good way to standardize these terms because of the lack of an international standard to begin with...LOL JAK8318:04, 5 February 2007 (UTC)
BTW I did not pull definitions from a dictionary, this is what somebody off the street would (probably) tell you if you asked for a definition.
JAK8304:35, 5 February 2007 (UTC)
There are some major differences in terminology between American English and British English in this field of technology. You almost need an English-to-English dictionary to translate from one to the other. Australian English also uses some unique terms. This makes it rather difficult to write an article that makes sense in the international context. RockyMtnGuy10:01, 6 February 2007 (UTC)
230 Volt that should be, it should not be 220V, nor should it be 240V!
> There are two basic standards for voltage and frequency in the world. One is the North American standard of 110-120 volts at 60 Hz, which uses plugs A and B, and the other is the European standard of 220-240 volts at 50 Hz <
This is not true, the entire Europe has been unified at 230V/50Hz for at least five years now. The western 240V went down ten and the ex-communist 220V went up ten volts to meet at 230V. This is well within the toleranca of appliances and now there is a lot of electricity export-import going on between the EU and Ukraine for example. 82.131.210.16208:44, 8 February 2007 (UTC)
IIRC the EU standard is 230V±10% which puts both 220V and 240V well within spec, some countries did change the actual average voltage, others just relied on already being in spec. Also iirc most of continental europe was 220V before not just the ex-soviet countries.
sorry dream on!!!
You think that they can just drop 10 V taking 240 to 230 in the U.K , all the equipment in the substations is based on a multiple of the hi voltage line , and not just some abitory system where they can drop 10 v
Basically to get 230vac in the U.K they would have to allow the network to be "overloaded" so that the voltge drops down to 230vac, now obviously this is fairly hard to accomplish and regulate effectively.
and in the U.K the spec is not 10%
That turns out not to be the case, as a little thought would suggest (Think hard: why would the regulatory authorities in all these countries accept a standard that could be damaging to electrical grid operations? Answer: The people who *set* the standards *run* the networks and know what they are doing.) Transformers in electrical substations have tapchangers that allow a variable ratio between primary and secondary voltage. Besides, as I understand the European situation, no-one is really initially changing voltages, instead the standard is being diluted to allow a wider range that covers everyone. Talk pages on Wikipedia would be shorter if we weren't so afraid of creeping credentialism. --Wtshymanski15:50, 19 October 2007 (UTC)
That's true. The standard is 230V±10%, which means anything between 207V and 253V. Neither the French at 220V nor the British at 240V have to change anything to meet it. RockyMtnGuy02:40, 20 October 2007 (UTC)
Also final distribution voltage is completely irrelvent to buying and selling power between countries. What matters for that is if the grids are locked in sync (a prerequisite for running in sync being running at the same frequency). if they are then they essentially become one grid once you stick some transformers between them, if not then you have to go via DC. I belive that the grids in continental europe from poland through to portugal are run in sync (the UK i know is connected by a DC link) but don't quote me on that. —The preceding unsigned comment was added by Plugwash (talk • contribs) 09:11, 8 February 2007 (UTC).
In North America, IIRC, the voltage is nominally 120/240V at the transformer, drops to about 115/230V at the circuit breaker panel, and may be as low as 110/220V by the end of the line. The actual voltage might be any of these, depending on where you measure it. The plugs themselves are rated for a maximum of 125/250V. RockyMtnGuy19:14, 15 February 2007 (UTC)
The all-important word here is nominal -- most devices will accept a range of voltages without any problems. It's only when you get into the extremes of low or high that problems beging to appear, which is under 90v or over 140v for 115v nominal devices. DMahalko (talk) 20:03, 15 May 2008 (UTC)
13 amps in Switzerland
I'll put my question here in domestic as well. I'm looking for information on 13 amp plugs and sockets in Switzerland. I have a 13 amp ceramic kiln that I want to plug in domestic, but the plug is unlike any socket in the apartment. It is three pin with the pins in a triangle and with the center pin being larger than the other two. Typical three pin in Switzerland is triangular, but with all pins the same size. I had been told that the sockets in the apartment were 13, but they could be 10. I need to check on that. If they are 10, then I'm wondering if it is possible to replace the lead and plug with a regular three pin and plug into the lower half of a 16 amp socket (which is five pin.) The dishwasher appears to do just that. Hope someone can understand all this. Thanks. --brough18:22, 14 February 2007 (UTC)
If anyone can find a spot for it, this is an image of an American 3-prong receptacle, grounded. It is outdoors and has protective, weatherproof doors over the sockets. Steevven1(Talk) (Contribs) (Gallery)03:05, 11 March 2007 (UTC)
I notice that someone put "more info on Japanese plug" on the to-do list. What info is needed? The Japanese plug is the same as the American plug. The only difference is that the approval agency markings are different.
If anyone wants, I have a few two-pin Japanese plugs (and a cordset) I could take pictures of. I don't have a female wall-socket, however. I'd just have to learn how to post these pictures onto Wikipedia.Stephanie Weil20:28, 19 March 2007 (UTC)
Japanese frequency
There is no explanation of why Japan uses two freqencies in different parts of the country. Anyone know why? --24.252.10.22817:15, 13 May 2007 (UTC)
I don't know for sure but i'd guess like most things electrical it's probablly historic. The thing with frequency is its a bitch to convert big motors and generators to run on a different one and its also a bitch to convert between frequencies. When joining the grids I guess they must have decided that a central converter station was more economical than paying for major changes to/replacement of/converters for all the motors and generators that would be affected by switching over half a country. Plugwash23:31, 17 May 2007 (UTC)
I think the problem is that in the absence of national standards, individual electric power companies adopted different standards. In the U.S. Westinghouse built their generators to run at 60 Hz, setting the North American Standard. In Europe Siemens built theirs to run at 50 Hz, setting the European standard. Japanese electric power companies apparently bought generators from both places, resulting in a mix of incompatible power systems. This isn't really unusual. Some third-world countries have quite a mix of different frequency and voltage systems. RockyMtnGuy03:38, 16 June 2007 (UTC)
NPOV!?
The following
"The reason that there are now over a dozen different styles of plugs and wall outlets is that when European countries adopted 220-240V electricity, for nationalistic reasons they developed their own unique national plug designs instead of agreeing on a European standard plug. In contrast, the 38 different countries which adopted the American 110-120V standard electricity also adopted the U.S. type A and B plugs."
doesn't make too much sense to me. I feel it is written in a confrontational style, partial to the US.
If you look at the map, notice that the green EU standard covers more space than the wine-red US one. Therefore I feel it is misleading to emphasize the "nationalistic reasons" when discussing Europe, while writing "in contrast, .. 38 different countries .. adopted the American .. standard".
I am slapping a npov tag onto this. Feel free to rewrite in a more neutral tone and then remove the tag.
For instance, if you say that "the British, the Americans, the French and the Germans all decided to have their own plugs" that's fine. Bunching together stupid europeans and contrasting that with the usefulness (as exampled by the adoption rate) of the American plug is not. America is simply only one of all the nations that "for nationalistic reasons" decided to go their own way.
Besides, please provide a source for the claim that the plugs were developed "for nationalistic reasons" instead of, say, because they were simultaneously developed or some other reason.
It could perhaps be also argued that each European country adopted their system for commercial reasons as well because there was less influence from big multi-national companies. There also were not the international bodies setting international standards of course. In most areas (not just connectors) the US ignores international standards and adopts there own standards. --jmb14:24, 15 June 2007 (UTC)
The U.S. has nearly as many people as all European countries (except Russia) combined, which means it has huge power to set standards. The problem in Europe is that, while most European countries are quite small, Europeans just will not get together and settle on a single standard because each country just has to run its own show in its own individual way. A European standards committee has proposed a standard European electric plug, it's just that the only country to adopt it has been ... Brazil. Meanwhile, in the U.S. it was not the government which set the standard, it was the electrical industry that settled on one standard through intense competition. Canada and Mexico fell into line because they wanted to sell and buy equipment to and from the U.S., followed by 35 other countries. RockyMtnGuy03:57, 16 June 2007 (UTC)
According to the map, Brazil doesn’t even use European plugs that’s what I get for not zooming in on the thing, and they happen to use both 230 and 120 both at 60 (a somewhat similarly unique situation to Japan). :) Most of Africa seems to though, probably as a result of French colonisation and such. The Koreas appear to be green to me too. -- Ralesk22:40, 23 July 2007 (UTC)
round pins vs flat blades
So which is better, round pins vs. flat blades?
Imagine a hypothetical organization that designed/picked a plug and socket based on its technical merits.
Imagine that it completely ignored backwards compatibility or compatibility with any other plugs and sockets on Earth.
What kind of plug and socket would it pick?
I would imagine that any one person would be convinced that *either* round pins *or* flat blades are better. So I would expect such an organization would never pick a mixture of 2 flat blades and 1 round pins, such as the "Type B (American 3-pin)".
So which is better:
all flat blades, like the C13 and C14 IEC connector and Type G (British 3-pin) ?
all round pins, like the Europlug and the Type D (Old British 3-pin) ?
Or would this hypothetical organization pick something entirely different? Perhaps something more like
IMHO, flat pins should be easier to cut in production and, with a flat inner contact on the female side, should provide less contact resistance. Round pins can be "touched" by a female contact just on a smaller surface. And I see no reason in mixing round/flat pins. Danilo Roascio11:20, 22 June 2007 (UTC)
If one started with a completely blank piece of paper, one would probably design a plug that had three flat blades arranged in a triangle, like the C13/C14. It would be as small as the American Type A plug, but have three contacts, like the Type B. The earth/ground contact would be wider than the live or neutral so it could not be inserted in the live or neutral sockets, and the earth/ground would also be longer than the live or neutral so it could activate a child-proofing mechanism, like the British plug. The bases of the live and neutral blades would be insulated so that people could not accidentally touch a hot contact while inserting a plug, like the Australian plug. It would be designed for 240 volts, 16 Amps and 60 Hz; and would be the only domestic plug in the world, replacing all the other types. Of course, we're not starting with a blank piece of paper so we're never going to have a plug like this. RockyMtnGuy05:39, 23 June 2007 (UTC)
You don't want a flat inner contact on the female side (and you won't normally find one in a socket designed to take a flat male plug). It wouldn't result in enough pressure to cut through oxidation and other films on the contacts. Instead, they use a smaller contact area (but still plenty to handle the current) and get the wiping effect every time you insert and remove the plug. As long as the conductor cross section widens out within a millimeter or so, there's really no need to have a wide cross section at the contact point. Bryan Henderson06:09, 24 June 2007 (UTC)
TOC vs. table -- ready, fight!
So, uh, what's up with the table placement? It looks like it's being pushed aside by the TOC, which feels it is more important. Because it gets pushed aside like that, it hangs down past the TOC and crushes the first section below the TOC. Here's a screenshot of what I see. It's definitely visually displeasing. I messed around with alignments, placing, etc., but I wasn't able to get it to look good. (In case anyone cares, I'm using Swiftfox 2.0.0.4, which is basically Firefox of the same version.) — SheeEttin {T/C} 03:52, 3 July 2007 (UTC)
My guess is whats happening is that on screens beyond a certain width the image next to the intro is pushing that table into the middle focring it up against the TOC, i've wrapped the intro and its image in a table so that it forms a rectangle that is gauranteed to stay above the TOC and the table next to it. I've also moved the intro image up to the very top alongside the disambig links. Tell me if it looks ok for you now. Plugwash21:32, 8 July 2007 (UTC)
There is ambiguity created after reading the article.
It is mentioned in the article that plug type D (Old british standard) is used in India. That seems to be true. But in one of the diagram it is shown that plug type K (Danish) is used in India which I think is not true.
Refactoring and redistributing content
The history of why 120/230 V and why 50/60 Hz is probably better covered at length in Mains electricity, with which there is considerable overlap. I propose to move the historical section out of this article; it will be easier to maintain if the history and origins are all in one place. Also see utility frequency. --Wtshymanski21:56, 17 August 2007 (UTC)
Title "History of plugs and sockets" inaccurate?
Having read the short section titled "History of plugs and sockets" I am left with the impression that the author intended the article to be for the US only. No mention is made of anything outside of the USA.
Statements such as "The original two prong electrical plug and socket were invented by Harvey Hubbell and patented in 1904.[1]" are not helpful in a global context. Many countries in the world had original 2 prong plugs which were not invented by Harvey Hubbell. Likewise the comment "The three prong plug was invented in 1928 by Philip F. Labre" appears inconsistent with the Wikipedia entry for Schuko, which claims that the 3 contact Schuko plug was patented in 1926.
I feel the easiest solution is to modify the title to "History of plugs and sockets in the USA". However as I am new to Wikipedia I would welcome the views of others before attempting any action.
Joe kibble14:07, 9 September 2007 (UTC)
If you have sources - be bold and write it! Though I suspect that the US history is as early as any history you're going to find. The problem is endemic to Wikipedia - rather than write nothing for a history section, a quick Web search turns up a US company (that has actually gone to the trouble of documenting some history) and so that's what gets quoted. Wikipedia research is often a mile wide and an inch deep (and if some bot changes those to SI measurements I'm going to join the Butlerian Jihad myself).
There's an amusing strain of anti-Americanism on the Wikipedia considering that the Wikipedia was invented by Americans, as was the Internet itself - it's like those pictures of the crowds yelling "Yanqui go home!" while wearing Coca Cola T-shirts. Don't doubt that if it furthered American national interests that those Florida servers would go dark in milliseconds - so much for the "international" en.wikipedia. And meanwhile consider the advantage that 350 million people can travel from the Arctic Ocean to the Rio Grande, from St. Johns to San Jose, with their portable electrical gizmos, and need never doubt that their hotel rooms will have a plug that will run their gear. Unlike a European traveller, who must pack a knapsack full of adapters because Denmark and Holland can't agree on what a wall plug should look like! --Wtshymanski15:11, 9 September 2007 (UTC)
We need more history of plugs. (did I mention that those standardized plugs I mentioned have been standardized for well over 50 years? I need to find old NEMA publications...) --Wtshymanski19:23, 14 September 2007 (UTC)
Well, if you really wanna get technical, the Netherlands and Denmark both agree on the same non-grounded plug -- two round pins. :) Stephanie Weil21:53, 9 November 2007 (UTC)
Colours of Wire
Is there really any point of having the UK, Ireland and Australia's standard wire colours for flexible cable, from before 1969, in the same table as current wire colours? All three of these countries now use different colours, and seperating them from other regions, which they're included in above, just makes the table look confusing. The same goes for the 'Standard wire colours for fixed cable' table. Although Australia still uses these colous for fixed wires, the UK no longer does so should be removed. Sneyton15:25, 19 October 2007 (UTC)
Australia and New Zealand use Brown (Phase), Blue (Neutral), Green/Yellow (Earth), in flexible cords, it's been like this for some years. Trumpy (talk) 03:03, 18 November 2007 (UTC)
In the UK, one still comes across quite a bit of wiring in the old colours. It should be documented somewhere but perhaps not here or in this way. Is there a separate article about electrical wiring colour standards? --DanielRigal (talk) 11:29, 18 November 2007 (UTC)
Slightly separate, but still on colours of wire, why, in an article about domestic plugs and wiring, is there a confusing (and ambiguous) list of 3-phase wire colours for EU fixed wire installation? I propose this should be removed and stick to the single phase wire colours (Brown for live, blue for neutral.) By the way, the ambiguous bit is the order of colours for 3-phase live - the new harmonised standard specifies BROWN - L1, BLACK - L2, GREY - L3. (article currently lists Black, Brown, Grey).Opep (talk) 18:04, 10 December 2007 (UTC)
Fair use rationale for Image:CCC (China Compulsory Certification) Mark.jpg
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What about the different grades of plugs? There is hospital grade (identified with a green dot), specification grade, industrial grade... I have no clue about what makes them. Could someone research and add this info here? Thanks Matias (talk) 03:00, 6 January 2008 (UTC)
In what country do these grades exist? What is meant by the term "grade" in this case? I think I understand what "industrial grade" means - more robust than usual construction and/or materials, but "hospital grade" and "specification grade"? In South Africa there is a variant of the standard 3-pin 15A plug/socket with the upper surface of the normally round earth pin flattened. This is used to "reserve" certain circuits for specific equipment such as critical hospital equipment such as respirators etc. Roger (talk) 20:41, 6 January 2008 (UTC)
In the US. Even a standard receptacle can be hospital, industrial, specification or audio (hi-fi) grade. See here for exemple: http://www.hubbell-wiring.com/Hospital.asp. I think (not sure) that their contruction and quality is different, even if the type of plug itself is the same. Matias (talk) 20:07, 24 January 2008 (UTC)
These are North American grades - see http://www.ul.com/regulators/ReceptacleGrades_Kurten_JF2005.pdf Under the North American Free Trade Agreement (NAFTA) they apply in the U.S., Canada, and Mexico. "Hospital grade" is more robust and reliable than industrial grade and is built to withstand severe abuse while maintaining reliable operation. "Specification grade" means it is built to US (and under NAFTA, Canadian and Mexican) government specifications, but otherwise is the same as industrial grade. The plugs and sockets themselves are the same design, and there is nothing (other than cost) to stop people from using hospital grade equipment in their private homes.RockyMtnGuy (talk) 17:36, 25 January 2008 (UTC)
Hospital grade equipment is much stronger and more robust than general purpose equipment because it costs money to build things stronger. Also, it can take quite a strong pull to remove a plug from a socket, because they don't want people knocking the plug for the heart-lung machine out of the socket by accident. It's not unreasonable to use it in a private home if you have small children. On the other hand, for sheer cost, you should try buying "military spec" or "explosion-proof" equipment. That's where the $700 hammer and $5000 coffee maker originated. It's so you can still build a shack and brew a steaming hot cup of coffee after your airplane has crashed. RockyMtnGuy (talk) 19:14, 29 January 2008 (UTC)
The "$700 hammer and $5000 coffee maker" were used to develop secret stuff such as the F117 stealth plane. The hammer really cost the normal price but the change was diverted into the secret account. Roger (talk) 20:43, 29 January 2008 (UTC)
This is an archive of past discussions about AC power plugs and sockets. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.
Ziltro 17:31, 3 February 2006 (UTC)
image in the article up until 17:11, 15 September 2006
nice image but the rather straight shot angle makes it a little difficult to see some of the defining features especially at smaller sizes.
2 French extension leads, added by ziltro, look pretty promising with a little work to extract one socket.
rotated and cropped version of ziltros image, now in the article. - Now removed and replaced with the next one Ziltro 04:46, 8 December 2006 (UTC)
Better late than never... is this good ? - Even made by Legrand, how French! This looks much better so I have replaced the article's photo. Ziltro 04:46, 8 December 2006 (UTC)
BS 546 2A 2P
BS 546 2A 3P
BS 546 5A 3P
BS 546 15A 3P
BS 1363
France / Belgium
NEMA 5-15
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