Talk:Edison screw

E26. Mion 00:32, 2 March 2007 (UTC)

Female Half
This article unfortunately discusses only the Male-half of the E-xx connector. The Female-half also deserves discussion, since it frequently is the source of the major hazards associated with this rather crude and outdated system of connectors.

The hazards arise from thermal ratcheting and from the thermal disintegration of the raw paper frequently used as insulation in the receptacle.

Has anyone figures on how many electrocutions per year occur attributable to insulation failure in these devices ?
 * I added a picture of the female half, anyways. A discussion of it is very much warranted, IMO Hustvedt (talk) 23:34, 14 January 2009 (UTC)
 * That picture disappeared from the article. Peter Horn User talk 16:02, 11 April 2020 (UTC)
 * Can you supply that picture again? Peter Horn User talk 16:08, 11 April 2020 (UTC)
 * [[Image:Light bulb socket E26 three way.jpg|thumb|50px|left|A three-way E26 light socket]] Mea culpa, it is still there. Peter Horn User talk 16:22, 11 April 2020 (UTC)

E26 / E27
Are these really two separate sizes, or two names for one standard size? And, although metric is now the international standard, these sizes originated in a non-metric culture, and it is surely no accident that this most common bulb base in the US actually measure one inch -- that article should mention this!-69.87.202.161 14:44, 13 May 2007 (UTC)

Utter nonsense. Technical pioneers of the late 19-th century, such as Edison, Eastman and Bell, were very strong metric proponents. Bell even spoke before a congressional committee promoting metric adoption. These pioneers made sure that standards based on their discoveries used rounded metric units. That is why we have metric based bulb screws, metric film sizes and other products of their involvement. More than likely, other American metric haters made attempts to re-describe these metric products in not so metric terms giving the illusion they originated in a non-metric culture. Even phonograph records later given inch trade names originated as rounded metric sizes. There never was a 12 inch record, it started out as a 300 mm, but the American industry tried to change it to inches and the nearest practical fraction they could find made the record diameter 302 mm. This is not 12 inch. The 10 inch is a true 250 mm and the 7 inch was a true 175 mm.

If you have any old records, measure them and you will be joyfully surprised they don't live p to their inch trade names. 68.105.199.216 (talk) 14:26, 15 July 2012 (UTC)

It seems like both E26 and E27 are actually one-inch diameter, and the E27 is longer, with a more pointy tip contact. So, E27 is a particularly bad example to use in the intro; I'll change it.-69.87.201.38 13:58, 5 June 2007 (UTC)

I was still confused on the E26/E27 issue. I found this (from http://www.ledlightbulb.net/store/index.php?main_page=index&cPath=4_6 ) :

"Ball bulbs with E26/E27 Base, E26 and E27 are standard medium Edison socket, They has same diameter screw in 26.38mm, Just the length of socket are different, The length of E26 is 26mm, The lenght of E27 is 27.5mm, They are the normal ubiquitous bulb socket in the world. The E27 Base can replace E26 Base." (bad grammar and spelling are copied as was)

That seemed to pin it down, except then I found this: http://donsbulbs.com/cgi-bin/r/b.pl/socket-db-e26-1.html

Looking at the drawings it seems clear that E26 bulb bases have a 26 mm diameter and E27 sockets have a 27 mm diameter except when looks at the detailed dimensioning on the drawings the diameters of both bulb bases are the same.

I did some more reading on the web and still wasn't exactly sure what was right. In the end, possibly the only way this will get resolved with certainty is to look at the relevant specifications which don't seem to be readily accessible on the web.

FWIW, I measured the height of some bulb bases that we had in our house (we're in the US) and found them to be almost exactly 26mm, but with my primitive measuring techniques I couldn't rule out the possibility that they were 27.5mm. Davefoc (talk) 20:42, 18 September 2009 (UTC)
 * Above are now two dead links. Peter Horn User talk 15:49, 11 April 2020 (UTC)

Reading the NIST screw base info from the 1950’s, the screw thread is just +/- 0.033” from a 1.000 inch nominal to crest and trough. The tolerance on the major and minor diameters is just +/- 0.003” for lamps, +/- 0.010” for lamp holders. The go/no-go gauges have a 0.003” pass/reject separation. It’s evident that although it would be possible to translate the dimensions to millimeters, changing any of the key dimensions by 0.07mm would result in a 100% reject rate. There is no reason to believe that any of the controlling dimensions has its origin in any metric dimension, it’s clearly a design that forms a rounded thread on a 1.000” cylinder. There is no reason beyond convenience to describe the base as 26mm other than it being the nearest whole integer for the major diameter. PolychromePlatypus (talk) 13:22, 29 September 2020 (UTC)

more details
"Most domestic and industrial light bulbs have standard fittings compatible with standard lampholders. The most common types of fitting are:
 * E12 or candelabra
 * MES or medium Edison screw (aka E26), used in the USA and Japan for most 120 and 100 volt lamps
 * BC or double-contact bayonet cap, used in the UK, Ireland and Australia for most 240 volt mains lamps (although MES is also common in the UK)
 * E14 / E27 screw fittings, used in continental Europe. (E27 is very similar to MES, but not identical.)

In each designation, the E stands for Edison, who created the screw-base lamp, and the number is screw cap diameter in millimetres. (This is true even in the United States, where other designations involving the diameter of the bulb itself are still given in eighths of an inch.) In North America, there are four standard sizes of screw-in sockets used for line-voltage lamps: candelabra (E12), intermediate (E17), medium or standard (E26), and mogul (E39). In continental Europe, these are instead slightly different: candelabra (E10 or E11), intermediate (E14), medium or standard (E27), and mogul (E40). There is also a rare "admedium" size (E29), and a very miniature size (E5), generally used only for low voltage applications such as with a battery. Bayonet bulbs have similar sizes, and are given a B designation.

Halogen bulbs often come inside one of these standard bulbs, but also come with pin bases. These are given a G designation, with the number being the centre-to-centre distance in millimetres.

General Electric introduced standard fitting sizes for tungsten incandescent lamps under the Mazda trademark in 1909. This standard was soon adopted across the United States, and the Mazda name was used by many manufacturers under license through 1945." -69.87.201.38 13:58, 5 June 2007 (UTC)


 * You, of course, mean The General Electric Company (GEC) of the UK, not to be confused with General Electric (GE) of the US. Only problem being that the MAzda light bulb company was nothing to do with GEC - and never was throughout its history.  It was a subsidiary of AEI - totally different company. 109.153.242.10 (talk) 17:10, 25 January 2012 (UTC)

Admedium
When I was a child, our family had a (G.E., iirc) mercury-arc sunlamp (a floor lamp) that had a conventionally-shaped screw-base bulb with an admedium base. The socket was large enough that a conventional bulb's base would be quite loose, and considering that the lamp operated base up, any conventional bulb would not stay in place. More recently, I have read that UV screw-base lamps sometimes have admedium bases, but, that's not reliable info. In appearance, the admedium base looked very much like an E26 base; only if looked at more closely did it seem a bit big.

Should admedium bases be included in the article? I'd say so.

Regards, Nikevich (talk) 14:27, 6 April 2011 (UTC)
 * Fixed. I was surprised it wasn't already in the table. Found it in the ANSI standard which you can look at for free on the NEMA Web site; oddly, to buy a hardcopy is $450, but the .PDF is free to download. I'd print it and mail it for a lot less, myself. --Wtshymanski (talk) 15:33, 6 April 2011 (UTC)

Actual role of Thomas Edison
I thought that Thomas Edison cut his light bulb research practically back to zero after the formation of General Electric, so did he have any role personally or via his lab in the development of this? And his bulbs had screw threads way before 1909. How did the 1909 version differ from earlier ones? See Lewis Latimer's 1890 book, (which was actually written years before) page 31, which says the lamps had a screw thread.. Page 73 of this 1884 book shows a screw thread which looks different from the one used 1909 to present. I have what I believe to be a pre-Mazda carbon filament bulb with the tip from evacuation which fits in a modern socket. An ad from 1910 for Mazda lamps says "Screw them into any socket just like the ordinary incandescents" indocating that the arrangement was not novel to the 1910 Mazda lamp.Edison (talk) 05:41, 2 March 2008 (UTC)
 * " Forty Years of Edison Service, 1882-1922: Outlining the Growth and ... - Page 80 by Thomas Commerford Martin says on page80 that the squirted filament was developed in 1894.  "Edisonia," a Brief History of the Early Edison Electric Lighting System" by Committee on St. Louis exposition shows what looks like modern Edison lamp base threads on page 108 and says on  that the changing of the screw thread took place with the change to squirted filament. I have seen no discussion of a change in lamp sockets being necessary when the carbon filament or metalized carbon Gem filament was replaced by the Mazda filamen starting 1909-1910, so I think the modern Edison screw thread can be dated to 1894, not 1909 as this article states. Edison (talk) 07:00, 2 March 2008 (UTC)
 * The basics of the Edison screw thread may date back to December 1880, although then the lamps had a wooden collar above the socket to hold while screwing them in or out, per the Paul Israel book. Edison (talk) 01:52, 3 March 2008 (UTC)

Which diameter are you talking about?
Perhaps I'm being stupid, or perhaps this is just something 'everyone' knows, but there are two diameters: the diameter of the peaks of the screw thread and the diameter of the valleys of the screw thread. My bulb has large diameter of 14mm and a small diameter of 12.5mm, so I'm guessing it's an E14, but it'd be nice to have the article explicit about that. —Preceding unsigned comment added by 81.102.157.139 (talk) 18:59, 6 March 2009 (UTC)


 * Not stupid. As defined in the ANSI and IEC standards, the diameter refers to the outside diameter of the thread (across the peaks). This is generally true for threads for practal reasons; if you wanted to make a 14mm male thread you know you would need a 14 mm rod and run a die down it!. ---CPES (talk) 21:47, 18 February 2014 (UTC)


 * A machinist refers to major, minor and pitch diameters of a screw thread. See Screw_thread.  Regards, ... PeterEasthope (talk) 16:06, 11 October 2016 (UTC)

E27 lamp-holder outer screwing tread
Hello

I want to know the name of the outer screwing tread of a E27 socket. The outer diameter is 40 mm.

Regards, Stef —Preceding unsigned comment added by 86.92.132.118 (talk) 18:21, 10 May 2009 (UTC)


 * That's not an E27 then, it's an E40. Unless you've measured something incorrectly. 193.63.174.211 (talk) 15:01, 25 January 2012 (UTC)

Need a corresponding article on bulb sizes
I don't know if it's part of this article or a separate one, but we need something on the various bulb sizes, like A19. I thought C7 and C9 were thread sizes, not bulb sizes, which is why I came to this article, but I'm still confused. Rees11 (talk) 14:48, 28 December 2009 (UTC)
 * You don't think that perhaps at that point you should be consulting a manufacturer's catalog or more specialized literature than an encyclopedia? Wikipedia is not the world's shopping guide or indiscriminate collection of facts and I think even the exhaustive listings of socket sizes is getting a little overboard. However, my anti-parts-catalog stance seems to be a minority opinion, as many Wiki contributors are happy to type in pages and pages of catalog information. It improves the edit count and bulks up the page count of the encyclopedia, and is much much easier than writing text that actually explains anything. --Wtshymanski (talk) 17:25, 28 December 2009 (UTC)


 * I actually agree with you about parts catalogs and miscellaneous lists in general. But I don't think what I'm asking for is a parts catalog. Thread and bulb sizes are standardized, and I wouldn't know where else to go for this information. I don't think I'm asking for anything covered by wp:not. Compare, for example, List of battery sizes. Would you consider that inappropriate? Rees11 (talk) 21:46, 28 December 2009 (UTC)

It is some good information to understand the LED Light Bulbs of future energy saving lighting.

The market already have the gu10,e27 and e14 led lamp,you can view led light for more —Preceding unsigned comment added by 183.1.58.167 (talk) 02:34, 8 November 2010 (UTC)


 * C7 and C9, or as well as I remember it, C7 1/2 and C9 1/4, are Christmas lamps sizes, each with a corresponding thread. There is also C6, which is long gone by now, but I remember up to about 50 years ago, which is a smaller bulb, thread, and designed for series strings. C6 is now a common size and shape for LED bulbs, but it is the plastic covering that has that shape. In any case, the thread sizes have names, but it might be common enough to describe them based on the bulb that they go with. Gah4 (talk) 20:08, 11 April 2020 (UTC)
 * OK, the C7 lamps have candelabra base, and C9 intermediate base. These bases are also used on other lamps, though. Not so long ago, I needed one for a dryer, and go the wrong one. Gah4 (talk) 20:14, 11 April 2020 (UTC)

In-article max current warning for MES sockets
The article says that the 25A maximum rating "may limit the output of low-voltage bulbs" (paraphrase...) - But, given that most "low voltage" (or more properly, extra-low (sub-25V) voltage) bulbs run at 12V, that's still 300W! Or in other words, exactly the same as the general upper wattage limit for these sockets. Are there many applications that run less than 12V through an MES socket? (9V would still = 225W, 6V = 150W ... would you seriously run a 150W bulb off a 6V supply? The wiring and thermal loss considerations start to become quite troublesome at that point, and it would only be practical for, e.g. specialist automotive applications (rally spotlights on a classic car?). It's much more likely that if you're running a low voltage system that you've got smaller, lower wattage bulbs using smaller and lower-rated sockets).

On the other hand, it's enough - if the overall cap is ignored - for 2.75kW at 110V (or 5.75kW at 230V!), matching or far exceeding the ratings of normal earthed/fused/RCD'd power outlets, so it might even be more accurate to say that this current limit ONLY applies to "extra low"-voltage bulbs (and then, only 12V and below; a 24V system would be capped at 12.5A per socket)... regular "low" (i.e. sub-1000V) bulbs have much lower effective current limits anyway; as low as 2.75A for 110V or 1.3A for 230V.

In all, it's a rather odd statement to make... 193.63.174.211 (talk) 14:55, 25 January 2012 (UTC)


 * I seem to recall that's what the GE publication said...it's hardly a critical limitation as you point out. Doubtless someone looked at doing some weird projection lamp with an Edison base and sadly turned away because it was only good for 25 amps; but life goes on in spite of this. --Wtshymanski (talk) 15:03, 25 January 2012 (UTC)


 * Some illuminating devices take more current than normal under certain conditions. For example a filament bulb typically takes 10x its operating current until it warms up (often other lamps in the same circuit will momentarily dim when a filament bulb in turned on, especially with lower voltage mains supplies). Low energy bulbs also take more current at start up due to the built-in inverter. I haven't researched this and only mention it as food for thought. ---CPES (talk) 21:15, 18 February 2014 (UTC)

Sticking one's finger in a light socket
Being a safety issue with this type of fixture, and a thing that sometimes happens and is talked about, isn't it notable enough to have coverage in this article? MarshallKe (talk) 02:08, 14 April 2016 (UTC)

Possible consolidation of overlapping WP articles on lamp caps and lampholders.
A discussion is taking place at Talk:Bi-pin_connector on the possible consolidation of overlapping WP articles on lamp caps and lampholders. Please make any comments there, rather than here. JimmiCheddar (talk) 18:22, 3 January 2018 (UTC)

Light bulb or incandescent lamp?
IP editor 38.69.12.5 recently replaced all occurrences of "light bulb" with "incandescent lamp."The edit summary was "An incandescent lamp is not a "bulb"" Yet "light bulb" is a common term for these devices as well as LED bulbs and compact fluorescent bulbs. Most people would expect a "lamp" to be a ceramic or brass item with a cord, switch and shade, into which a light bulb is screwed. "Incandescent lamp" is inaccurate, given the other two common light bulb types using the base.accurate but less common than "light bulb." I am reverting the edit pending development of consensus here on the talk page, per WP:BOLD. "Incandescent light bulb would be accurate for uses before the compact fluorescent and LED were developed. Halogens are technically incandescent, but also deserve proper distinguishing. Edison (talk)
 * I am in the process of restoring some of the parts of the major edit by IP editor 38.69.12.5 which improved the article. Edison (talk) 21:59, 10 April 2018 (UTC)

Why did I pinged? I have nothing to do with whatever this is. Mr. C.C. Hey yo!I didn't do it! 03:58, 14 April 2020 (UTC)
 * I pinged you because you had a runin with User:Wtshymanski on his talk page I'm having a runin now. Peter Horn User talk 16:14, 14 April 2020 (UTC)

Profile
The profile of the Edison screw thread is missing as well as the threads per inch. Peter Horn User talk 01:45, 11 April 2020 (UTC)
 * I found the threads per inch within the article, but the profile, which somewhat resembles that of a knuckle thread, is not there. Peter Horn User talk 14:42, 11 April 2020 (UTC)
 * I found Edison thread Peter Horn User talk 19:20, 11 April 2020 (UTC)
 * The use of (a) German language link(s) occur(s) in other articles such as ISO metric screw thread. It is not unusual. In this case this link is the only one that shows me the profile. Other screw thread articles show profiles. Peter Horn User talk 18:06, 13 April 2020 (UTC)
 * and . User:Wtshymanski, what do you not understand? The use of external links in languages other than English is not uncommon in other Wikipedia articles because at times it is the ONLY way to have a reliable source. So, your "objections" are specious, ignorant and disruptive. That said, your user page tells nothing about you and your talk page is...there are no words to describe it. Peter Horn User talk 22:23, 13 April 2020 (UTC)
 * German-language-speakers have their own version of the Wikipedia. This one is in English. A reference in Germam, Dutch, Chinese, or Sanskrit is not useful to English speakers. There is almost certainly an English-language document that gives all the happy little details for someone wanting to turn his own threads to fit a light socket, but is such minutia appropriate outside of a textbook or handbook for machinists? --Wtshymanski (talk) 22:33, 13 April 2020 (UTC)
 * This is the English language version Peter Horn User talk 01:25, 14 April 2020 (UTC)
 * Give me a break. Edison threadx are rolled. Not turned on a lathe. At random the following articles could be used by machinists. ISO metric screw thread and British Standard Whitworth, Get with it. Peter Horn User talk 02:02, 14 April 2020 (UTC)
 * You are assuming that Wtshymanski actually checked the reference out before he started yet another edit war purely for the sake of an edit war. He has a long long history of this. 81.156.12.32 (talk) 12:42, 14 April 2020 (UTC)
 * The original link was in German and he objected to that. All said, thanks for tipping me off. That character needs to be put in his/her place. Peter Horn User talk 16:22, 14 April 2020 (UTC)


 * Apart from a German flag, the text of the link was in English. If you can put Wtshymanski in his place, then good luck to you. Others have been trying for over ten years. But WTS is very slippery. Trying to curtail his tendentious editing is like nailing jelly to the ceiling. 81.156.12.32 (talk) 16:25, 14 April 2020 (UTC)
 * How come WTS was never blocked? Peter Horn User talk 17:41, 14 April 2020 (UTC)


 * Oh, he has an impressively long block log, but has always dodged an indefinite block. This is a riveting read and will give you a fairly good idea. 81.156.12.32 (talk) 17:46, 14 April 2020 (UTC)
 * You're not kidding! I added my comment here Peter Horn User talk 18:57, 14 April 2020 (UTC)


 * You may as well revert it because RfCs on individuals behaviour are now deprecated so no one is looking. The only available avenue now is WP:ANI, but WTS is no stranger to that venue either. 81.156.12.32 (talk) 12:56, 15 April 2020 (UTC)
 * What section at that venue? I'll keep that in mind if WTS pops up again. Peter Horn User talk 21:38, 16 April 2020 (UTC)
 * If one gets enough sock puppets to agree with you, you can get anyone blocked. --Wtshymanski (talk) 20:20, 18 April 2020 (UTC)

french inch
E27 and E14 are one pouce and half pouce. Is this a mere case? thanks. 151.29.149.29 (talk) 18:51, 19 January 2024 (UTC)