Talk:Mains electricity/Archive 1

Archive 1

50 vs 60 Hz

I'd like to point you guys here to a discussion at the science ref desk: Wikipedia:Reference_desk/Science#frequency_of_electricity, which has a link to a useful text: [1]. I'm not sufficiently into this to incorporate this info in the article, so if anyone wnats to pick this up, here it is. DirkvdM 11:09, 9 February 2006 (UTC)

Thanks!

Atlant 11:54, 9 February 2006 (UTC)

110/220V

I remember back to my schooldays that the main reason for 110V was not that the voltage was safer, but that the first electric arc lamps needed as voltage supply most ideal 55V.
Therefore this allowed with 110/220 Volts either 2 or 4 lamps in line.
Who can confirm? --Tobsi 12:39, 15 January 2007 (UTC)

Merge with Mains power systems

I don't know why we have two articles talking about essentially the same thing - the Mains power systems article used to be a list of the world's plugs but now overlaps this article completely. Let's refactor this and get rid of one ( or spin the plugs list out and merge what's left). I've got a long weekend coming up and might just get to this. --Wtshymanski 20:25, 29 June 2007 (UTC)

I think it would be better to go the other way, put mains power systems back to its old title and move any general information from there to here. Long lists that will probablly be never featured as they are so damn hard to reference well should be kept seperate from article prose imo. Plugwash 21:47, 30 June 2007 (UTC)

First power

I'd like to know when mains electricity was first implemented, i.e. when was mains power first switched on? I am a lemon 02:13, 26 May 2007 (UTC)

September 4th, 1882. Probably in the evening. Of course it depends on where you are. It might have been as early as September 1881--Wtshymanski (talk) 18:44, 20 November 2007 (UTC)

RMS vs peak-to-peak?

It seems worth mentioning on the page that throughout this discussion, we're referring to root-mean-squared voltage, not peak voltage. (Or vice versa, if I'm incorrect!) Teejaydub (talk) 01:04, 23 May 2008 (UTC)

Lists by country

I'm almost clueless about the science of this subject, and was looking for a list of electric service (voltages and plugs, etc) by country simply for travel purposes. I finally found it at 'mains power supply' which has a link to it in this article, but it is all very confusing for the uniformed. The overview of the different supplies in this article is great but maybe a line could be added to 'refer to the 'mains power supply' page for the list by country'. I am not quite sure how I got to this page in the first place being as I am Canadian and don't use the word 'mains' so something worked in the links and redirects (though I do feel I got lucky). Maybe with all the different terms used around the English-speaking world for the stuff that comes out of plugs* a list page might help.
* I have lived in Ontario and Quebec and we do use 'hydro' a lot in these provinces, though mainly in relation to paying the bill (Quebec is the big hydro producer but sells to Ontario and the US). Simply the word 'power' is used for things like outages, connecting (ie. 'turn on/off the power') etc. --Yickbob (talk) 16:21, 1 June 2009 (UTC)

History and adoption

What % of people around the world have grid power? How has this number changed over time? Or could we see statistics for historical adoption on the U.S. (which might be easier to get)? -- Beland (talk) 18:27, 19 March 2010 (UTC)

Linking to electrification. -- Beland (talk) 01:42, 6 May 2019 (UTC)

australian innacuracy

australia is not included in any "european 230v harmonization" our mains were are and remain 240v 50hz. see http://www.accesscomms.com.au/powerplug.htm for accurate information on our mains, phones etc.. —Preceding unsigned comment added by 210.49.121.82 (talk • contribs)

I'd heared that australia was like the uk, e.g. accepting 230V as the official standard but not actually chaging anything in reality. That site is by no means a primary source and certainly doesn't disprove this. Does anyone here have access to relavent up to date australian standards to check? Plugwash 10:15, 23 April 2006 (UTC)

It isn't an inaccuracy at all... Australia adopted the 230V standard for the nominal supply voltage on the 23rd of February, 2000 (as a part of AS 60038-2000) - whether or not this is because of what continental Europe (or the UK) has done I cannot say for sure but I have been reliably told that it is to conform to the 1983 IEC program to achieve an international standard of 230 V (for 50Hz systems) by 2003... The allowed tolerance either side of 230 V is +10% and -6% and is also contained in AS 60038 - therefore any voltage between 216.2 V and 253 V is within spec... You are correct in saying the physical voltage has not changed because 240 V is still within the allowed range... Actually I measured the mains voltage today when at work and had 246 V on phase B and 243 on phases A and C - while those figures do seem high bear in mind that they are measured unloaded and of course fall back further inder higher current conditions... They also vary slightly depending on your distance from the distributor you're suplied from. Anthrass 03:19, 16 January 2007 (UTC)

Since then I've checked voltages in a few areas around the city of Sydney as a part of my work - the lowest I've found was 225 V and the highest 252 V Anthrass 11:31, 1 February 2007 (UTC).

As a further follow up to this I can comfirm that in the Sydney region at least we are in the process of physically changing voltage tap settings on transformers to harmonise with Europe - the driver behind this is the widespread adoption of PE Cells as a source of power. The consequence of this is that distribution voltage rises as more PE Cells are deployed. This impacts 240V countries (like Australia) more than 230 or 220V countries because the voltage is higher to begin with. As most of the inverters used here are also used in Europe, the higher voltage can cause problems... Hence the move to change the physical voltage to the same as that of Europe. The page that the original poster put up is now a dead link. Anthrass (talk) 12:24, 19 July 2013 (UTC)

"Mains electricity " is not logical

Since "mains" means "electricity", then "mains electricity" means "electricity electricity". Please, correct the article title to "Mains" or "Mains power".--24.186.223.176 (talk) 01:41, 16 August 2012 (UTC)

Well there's also gas mains and water mains and sewer mains, so the terms are not synonymous. You need them all for a quality life-style. --Wtshymanski (talk) 19:52, 23 October 2012 (UTC)

so why mains with an s? — Preceding unsigned comment added by 72.47.30.187 (talk) 17:34, 18 May 2013 (UTC)

Consult a dictionary. ElectricTattiebogle (talk) 21:25, 28 April 2014 (UTC)

Since there is no error found in the map, please let the accurate (not perfect though) knowledge spread

Please do not set any unattainable perfectionism goal, otherwise no map can be used as long as there exists a territorial disputes. Genhuan (talk) 04:05, 24 February 2015 (UTC)

The reference to "territorial disputes" does not relate to the reasons given for removing the map.

All material used on WP must be properly sourced, the map Weltkarte_der_Netzspannungen_und_Netzfrequenzen.svg is not.

The map claims to be based on Mains_electricity_by_country but does not actually represent the same information, a glaring example would be Russia!

For a map to useful it must give an impression of variations across the world in an easy to understand manner. The creator of Weltkarte_der_Netzspannungen_und_Netzfrequenzen.svg has tried to squeeze too much unnecessary information into the map making it too difficult to use, especially with the subtle shading used. A useful map would differentiate only between the two voltage ranges (100V to 130V and 200V to 230V) and the two frequencies.

This article does not purport to describe the voltages and frequencies used in different countries, that is done at Mains_electricity_by_country to which this article makes reference. A map is therefore not relevant to this article.

A map should not be added to this article unless a consensus has been reached here. FF-UK (talk) 13:04, 24 February 2015 (UTC)

European 230 V harmonization

The article says that those countries that when Europe was harmonised to 230V those countries that used to have 240V supplies e.g. the UK retained it. I was under the impression that the supply was actually reduced to 230V, which meant (don't laugh) that kettles took longer to boil and toasters longer to toast. was this just a myth? Mintguy (T) 17:56, 4 May 2004 (UTC)

The article is at least partly incorrect in saying that European countries that used to supply 220 V continue to do so. Germany, for example, has actually increased the voltage to 230 V in a process that took about a decade. I believe the situation is similar in most European countries, and wall sockets do actually supply 230 V. Britain is different in that it has not taken steps to reduce the voltage to 230 V, except in Northern Ireland, where mains voltage is actually 230 V. -- 62.159.244.133 03:34, 7 March 2006 (UTC)

I measured the mains voltage in Cambridge, England, about 15 minutes ago, with a multimeter accurate to 0.5%, and got 241 volts. This is the same as I measured in Birmingham about 5 years ago. So I'm convinced the UK mains supply remains at 240V nominal. 131.111.228.219 (talk) 14:06, 17 March 2008 (UTC)

My supply voltage measures between 240 and 250 v for about 90 per cent of the time in Essex, England. It seems 'harmonisation' was a paper exercise not affecting the actual voltage. — Preceding unsigned comment added by Historikeren (talk • contribs) 21:32, 21 November 2012 (UTC)

Indeed, the "harmonization" exercise initially was nothing but a juggling of the allowable tolerance in order to allow the existing 240V +/-6% standard to be reclassified as nominally 230V for political reasons. The absurd asymetrical +10/-6% tolerance is the result. It's quite likely, however, that over time as local distribution transformers are replaced the nominal voltages will become 230V with a symmetrical tolerance. Given that transformers generaly have a service life measured in decades, it's likely to be quite some time though. 97.84.107.236 (talk) 18:24, 20 August 2015 (UTC)

Standards

As of late June, 2007, the article has very limited information about standards, although the discussions on this page provide some of the background. The current U.S. consensus standard, ANSI C84.1-2006, is a long-term development starting with Utilization Voltage Standardization Requirements (Edison Electric Institute publication J-8, 1942). A critical issue currently unmentioned in the article is the distinction between service voltage (at entry to customer premises) and utilization voltage (at entry to equipment). That is the source of some of variations mentioned above. The U.S. NEMA organization now makes the C84.1 standard publication available for download at www.nema.org/stds/complimentary-docs/upload/ANSI%20C84-1.pdf. Readers will find that the Forward section provides many details of this standard's background.

Notes

1. In Canada we might say during a power failure "The hydro's out" or "I have to read the hydro meter and pay my hydro bill" or "That car hit a hydro pole", but if we plug something in, it's just called "plugging in" and not "connecting to Hydro" - your new house might be "connected to hydro". Anyway, I don't think the usage of "mains" is exactly equivalent to "hydro" in Canada. More of a Wiktionary issue, I suppose.
2. I would really like to see a citation for the Tesla statements on preferred voltage and frequency.
3. One reason Edison may have preferred 110 V for lamps is that it is easier to build a lamp for 110 V than for 220, and it is more rugged and (very slightly) more efficient.
4. I don't believe the claim that motors are less efficient at 50 Hz- for a given mechanical power output theoretically they may be a little larger, but I would expect hysteresis and windage losses to be lower. I don't think there's a "20% difference in efficiency between 50 Hz and 60 Hz motors.
5. The article says things like "20% less efficient"...that what?
6. Again, fascinating that early electrification in Europe was said to be 110 V (probably based on imported American lamps, at least for a little while). A cite would be great.
7. Americans are not "stuck" with the "problems" of lower voltage. For most appliances that you can lift with one hand, the minimum wire size is governed more by the physical strength of the conductors, so you might well use a lower voltage since you must have the copper anyway. Incandescent lamps are more rugged and slightly more efficient at 120 V compared to 240 V lamps in common household sizes. Usually a home has very few "high power" appliances that need more than approx. 1500 Watts, so it's really not that inconvenient to have 120 V distribution. True, a 3000 watt electric kettle would boil water much faster than our Canadian 1000 watt kettles.

I know I should be bold and fix some of these things myself, but I'd appreciate some comments. Tesla is everywhere in the electrical articles, but sometimes there's no references, or the references don't apply to the claim. --Wtshymanski 17:27, 8 Jun 2005 (UTC)

note: i'm british what i say here primerally compares to the uk and to a lesser extent the small amount i know about the rest of europe

afaict you americans get arround most of the problems of the lower voltage by a combination of running split phase into homes and having more transformers placed closer to the properties. The main effect that ordinary people would notice is that you have far less power availible from your normal socket outlets. you'd need a special cuircuit for a 3KW heater or fast boil kettle. We don't we can just plug them in. Plugwash 18:44, 8 Jun 2005 (UTC)

Canadian here...a species of North American. The other hand-held appliance that I would see benefitting from 240 V would be a hair dryer - do these come in ratings larger than 1200 W or so in the UK? I don't imagine rural or low-density distribution is any different in the UK than in Canada or the US - in high-density developments, say with lot widths less than 30 metres or so,or row housing or apartment blocks (you'd say "flats", I think), it's quite usual to find several homes sharing a pad-mount transformer, usually connected to homes by underground cable. In low density areas, say more than 100 metres frontage per lot, it's a pole-mounted transformer shared by only a couple of homes at most (assuming there's two homes close enough to share), fed by single-phase medium voltage (12.47 kV line/line in my area, but 4160 V is quite common too - I was involved in a project to uprate the voltage distribution for a small town a few years ago, they got rid of all their 2300 and 4160 and moved to 12.47 kV). Electric kettles are uncommon in the US but typical in Canada - we just wait longer for our tea. But there's no advantage to 240 V for table lamps, and various small electrical appliances...once the draw is less than a couple of amperes, the wire size is limited for mechanical reasons, not for current capacity.

--Wtshymanski 22:11, 8 Jun 2005 (UTC)

In the UK, the power distribution in urban areas is mainly underground, with the 240V running from fewer, larger 'substations', not the many pole-mounted transformers of the US. 131.111.228.219 (talk) 14:09, 17 March 2008 (UTC)

It's been a couple of weeks...I've rewritten the paragraph and removed many embedded comments. I wonder if there is a study somewhere of electrocutions/TWH domestic electric energy use, sorted by wall-plug voltage? That would speak somewhat to the safety of the two respective systems.--Wtshymanski 16:16, 26 Jun 2005 (UTC)

Well we brits plug our washing machines dishwashers, 3KW heaters and small single ovens into normal sockets. You north americans afaict need special circuits for them. Plugwash 11:27, 18 April 2006 (UTC)

True, but that’s not much of a bother, you just have to plan more for where you want your large appliances and run the power accordingly. What is really annoying is electric construction tools that run on 240V. It can be hard to find 240, and unless you have an electrician on site, you could be stuck. One trick is to run two plugs to 120V, but then you still have to find access to two 120V circuits at opposite polarity within range of your extension cords. Wiktard 22:28, 9 May 2006 (UTC)

I have to agree that the oft-quoted (in Britain, Ireland and other 240 countries) "problem" of North Americans being "stuck" with 120V really isn't a problem at all, since the 3-wire 120/240V service with heavier loads running on 240V has been the norm for many decades. Obviously there are advantages and disadvantages: Lower shock risk versus heavier cables for a given load etc., although in some cases the latter is somewhat offset by the use of a multiwire circuit anyway (e.g. the typical dedicated 3-wire dishwasher & garbage disposal circuit). As a Brit who now lives in the U.S.A., I'm familiar with both systems and have worked extensively with both. The perceived "big problems" of "being stuck with 120V" for most small appliances isn't a problem at all. Although when I remodel our kitchen in the next couple of years, I am going to install a 240V 15A outlet just for a British kettle! 97.84.107.236 (talk) 18:49, 20 August 2015 (UTC)

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Better?

Which is better? 50Hz or 60Hz? Why? Which is better 110V or 220V? Why? —The preceding unsigned comment was added by Frap (talk • contribs) 11:43, 10 May 2007 (UTC).

Whichever one you currently have, of course! Seriously, there are technical reasons to favor or disfavor either frequency and either distribution voltage. See War of Currents for some amusing early history. And Google will find you many, many sources of info re: 25 Hz, 40 Hz, 50 Hz, 60 Hz, and even other distribution frequencies!

Atlant 12:22, 10 May 2007 (UTC)

I've read the War on Currents article, but it was about the history of the war between AC and DC. Didn't explain what I was asking. -- Frap 18:11, 10 May 2007 (UTC)

Check out utility frequency and mains power systems for discussion, although the question as framed is quite meaningless and un-answerable. "Better" is a comparison, not an absolute. --Wtshymanski 20:49, 11 May 2007 (UTC)

Then what is the advantage/disadvantage of high/low voltage/frequency? -- Frap 00:21, 18 June 2007 (UTC)

Like many questions, it depends. Look at the two articles and tell me what's missing from them to answer your question; if the question has any meaning at all. If there was an overwhelming advantage, the whole world would use the same system; there isn't, and it doesn't. --Wtshymanski 17:51, 18 June 2007 (UTC)

Even when one is better, there is a large cost to transition. I suspect that today the optimal might be higher than 60Hz, but there is no thought to changing it. Gah4 (talk) 21:39, 13 September 2017 (UTC)

British term?

This is a British term, right? Is it used in Australia, South Africa, New Zealand? What about Canada? -- Zoe

It's used in Australia and New Zealand, and I've seen talk of "mains hum" in US publications (which they generally say is 60Hz, actually it's far more often 120Hz in the US and 100Hz in Australia, but that's another story). So my guess is that it's a term in most of the English-speaking world if not all of it. Andrewa 06:35, 24 Sep 2003 (UTC)

Actually no, the mains hum you're speaking of, is in fact the fundamental frequency of either 50 or 60Hz, I'm not sure where you got that idea from. Trumpy (talk) 06:21, 18 September 2017 (UTC)

The mechanical vibration of a transformer will be at twice the AC frequency, as wires, or other parts, move on both halves of the cycle. RFI from discharge lamps, such as fluorescent lamps, will also be on both halves of the cycle. Hum in audio circuits might be direct coupling to the AC line, but could also be ripple from a full wave rectifier, at twice the line frequency. I suspect that 2f is the more common case. Gah4 (talk) 19:17, 18 September 2017 (UTC)

Yes, it's British. Merriam-Webster says, "British: of or relating to utility distribution mains." I've never heard it in the U.S., and the first 100 results in Google and all the examples in the OED seem to confirm that it's not used there. The U.S. and Canada have 270 million native English speakers, versus less than 100 million native speakers of English in the U.K., Australia, New Zealand, and South Africa. I think the article title should be changed to Household Electricity, or perhaps Utility Electrical Standards by Country. 176.67.86.40 (talk) 05:07, 5 December 2013 (UTC)

U.S. voltage question

There's a very useful looking PDF (202KB) at http://www.user.fh-stralsund.de/~emasch/800x600/Dokumentenframe/Kompendium/Internationale%20Spannungen/0921271x.pdf but it lists four voltages for the USA: 115, 200, 230 and 277. For Canada it's 110, 115, 200 and 230. These are load voltages not line voltages, so if anything they should be on the low side. So the ommission of 110v from the USA is strange to me, I had previously believed that to be the standard US voltage. Can any US resident help here? What's going on? Andrewa 20:39, 24 Sep 2003 (UTC)

There are only two U.S. standard voltage but they are variously specified. The lower of the two is specified as 110, 115, 117, 120, or 125 volts, while the higher of the two is an exact double.

The original voltage was 110. By about 1940, this had increased, by convention, to 115 -- an inconsequential change, and acompanied by a shift in electrical distribution voltages from 2200 to 2400 volts while the winding ratio on transformers remained 10:1.

Then, considering the inevitable voltage drop between the utility metering point and the point of use, it became common for power companies to supply 120 volts with the presumption that a 5 volt drop in a building's distribution system would lead to 115 volts at the point of use. The most correct nominal voltages today is 120 (for supply and distribution) and 115 (for utilization equipment, like motors, appliances, and light bulbs). These figures are doubled (230 and 240) for certain equipment that requires more power, like clothes dryers and ranges, because of the midpoint-grounded way of doing things in North America.

277 volts is used for industrial lighting, and is the wye-connected voltage present on a 480 volt 3 phase delta system. 3 phase 208Y/120 is used in commercial and light industrial applications, and the 208 portion is sometimes specified as 200 volts for utilization equipment, again taking a small voltage drop into account.

Hope this helps.

Yes. The page and the power connector page are both looking a lot better now. Andrewa 10:29, 25 Sep 2003 (UTC)

A 5% change is not inconsequential for incandescent lighting, but is for most other uses. Gah4 (talk) 19:21, 18 September 2017 (UTC)

Why nothing about current?

I would like to see the article cover typical current limits in various countries. For example, early 20th century US residential power typically limited current to 15A per branch circuit and 60A (times 2 for +120V and -120V) for an entire house. Mid-century service was still 15A per branch but gradually 100A service became more normal for homes. Then in the late century (I don't know when) at some point 20A per branch circuit became a standard for new wiring. And with the proliferation of electronic devices 100A service is now considered bare minimum.

I don't know how to validate any of this information, although looking at past issues of the National Electrical Code would provide good information for the USA.

I was originally interested to know how many amps are delivered at a typical residential power point in the UK. I have no idea how to get this information.

Norman Ramsey (talk) 00:14, 21 March 2009 (UTC)

I was looking for similar information, curious about 120V vs. 240V countries. -- Beland (talk) 02:47, 24 January 2011 (UTC)

I think the only reliable information on this matter we can use actually exists here already, in article about AC power plugs and sockets as the effective maximum current in normal outlet-serving circuit would be the maximum rating of the socket and no more.

Do some countries actually hack in stone how much power a single housing unit may draw? At here we just have an expected draw of a locale and the circuits are rated according to that. --87.100.236.74 (talk) 03:18, 13 January 2013 (UTC)

In the early part of the 20th century it wasn't unusual for smaller U.S. homes to be supplied with a 2-wire 120V only service at as little as 30 amps. The 120/240V supply at 60A or more became pretty much the standard after World War II, with the later increase to 100A or more as the minimum standard in later years. Obviously there has been considerable overlap in supply types at various times.

With regard to 15 vs. 20A branch circuits, both have been and still are common for various purposes. The small appliance circuits to feed general-purpose outlets in the kitchen and dining areas have been 20A for many years, with two such branch circuits being required by the National Electrical Code since 1959. Remaining general-purpose circuits (outlets in other areas of the house plus lighting) can still be 15 or 20A today, with the load for a regular dwelling calculated on the basis of 3 watts per square foot. 97.84.107.236 (talk) 18:44, 20 August 2015 (UTC)

The usual case for US wiring is 20A branch circuits with outlets allowing for 15A maximum. A 20A outlet (different plug shape) needs its own 20A circuit. As far as I know, the change to 200A service came along with electric stove, oven, water heater, and dryer, the common high current devices in residences. Gah4 (talk) 19:32, 18 September 2017 (UTC)

220-240V lamps working on 110V

I have a doubt regarding the use of lamps. The normal low voltage lamps such as 12V 50W halogen, PL lamps such as 26W working on transformer, Metal halide and Sodium Lamps working on Transformer. Is the lamps are same when we use 110V input transformer and 230V input transformer? Any one can tell me with technical details about this. —Preceding unsigned comment added by 86.96.229.86 (talk) 15:50, 22 September 2010 (UTC)

Low voltage halogen lamps, with a regulated power supply should be able, with appropriate power supply, to work on any line voltage. Many fluorescent lamps have a running voltage over 120V, such that a transformer ballast is needed. At 220V, a 40W (4 foot) fluorescent lamp can run with a simple inductor ballast. 20W or less run on a simple inductor ballast at 120V input. Transformer ballasts might have multiple input taps for different input voltages. That is for iron core ballasts. Many now use electronic ballasts, which convert the input up to some higher DC voltage, switch at 20kHz or so, run through a ferrite core transformer, and then usually a series capacitor. Like many switching power supplies, they can run off a range of input voltages. The operating voltage for arc lamps depends somewhat on the geometry, and more on the output power. Gah4 (talk) 16:16, 3 November 2017 (UTC)

Frequency stability

The person editing from IP address 199.125.109.127 says that the grid run 0.0025% fast or slow to catch up. This address seems to originate sensible edits, but it would be very good to have a reference since I haven't seen this mentioned anywhere. This may vary on a utility-by-utility (or NERC area, etc.) basis anyway. And the value of 0.0025% is only 2 seconds a day, too small to be noticeable anyway. --Wtshymanski 18:19, 16 August 2007 (UTC)

Corrected to 0.02%, with references. The whole point is that it isn't supposed to be noticeable, so 0.0025% would make more sense than 0.02%, which pretty much guarantees that clocks are off by about 10 seconds half the time. I'm amazed that anyone puts up with such lack of precision. 199.125.109.127 06:02, 1 September 2007 (UTC)

Nowadays people don't, most clocks are battery operated quartz ones. Clocks that use the mains supply for their timing used to be quite common, but are much less so now. But the power companies still keep the frequency in sync I presume. 131.111.228.219 (talk) 14:13, 17 March 2008 (UTC)

Would it also be correct to note the effect that the frequency choice had on early electronics? For instance, the PAL and NTSC television standards seem to depend on the underlying 60/50Hz clocks beneath. That seems pretty certain. However, from there, you get the Commodore 64 which ran at 1.023 MHz in NTSC countries and 0.985 MHz in PAL countries. I can't get the numbers to work quite right for me, though. The difference of 50/60 is 83% while the difference between .985/1.023 is 96%. --Mdwyer (talk) 22:32, 19 November 2007 (UTC)

There is a dot clock for the video output, which might be different for PAL and NTSC. If you look at the C64 schematic (in the users manual for every one sold) it is really obvious what they did. There are two sides, processor side and video side, with a PLL frequency converter in between. The early design had separate clocks, which, depending on exact frequency, make visible artifacts on the screen. So, they are phase locked with some simple ratio, such as 8:13. The ratio can be different, and so the clock ratios are not the same. Gah4 (talk) 16:25, 3 November 2017 (UTC)

IIRC the reason for using field clocks the same as the power distribution frequency was so that interference from the mains would be static or very slow moving rather than rapidly moving. Plugwash (talk) 16:27, 20 November 2007 (UTC)

Mostly when power supply regulators weren't as good as they are now. NTSC change the field rate from 60Hz to 59.94Hz, allowing for a slow visible effect if the power supplies didn't improve. Gah4 (talk) 21:42, 13 September 2017 (UTC)

50 Hz

The German company AEG built the first European generating facility to run at 50 Hz, allegedly because the number 60 did not fit into the numerical unit sequence of 1, 2, 5….

What a silly reason for the world to be at two different frequencies. Is this related to Preferred numbers? — Omegatron 02:14, 18 April 2006 (UTC)

As I understand it, at the time that this was being decided, US had better transformer material (silicon steel) that Europe didn't yet have. 50Hz requires bigger transformers than 60Hz. The old tradition for airplanes was 400Hz, keeping weight down. The usual PC power supply converts the incoming AC to about 300VDC, and then to about 20kHz AC into a tiny ferrite core transformer. This change came from the availability of transistors to run at this voltage and power level. Gah4 (talk) 21:21, 13 September 2017 (UTC)

Regarding the recent edit and revert regarding arc lamps and metric values, I believe the US silicon steel is the actual reason, but don't have a source. Gah4 (talk) 16:26, 3 November 2017 (UTC)

Silicon iron, metallurgically, although WP calls it a steel.

Note also the long history of electric railways at 162⁄3Hz AC, because this was the highest frequency that the traction motors could work at. France then moved to 50Hz post-WWII. Andy Dingley (talk) 18:59, 3 November 2017 (UTC)

I searched some for the history of Si steel and 60Hz decisions, but it isn't so easy to find. Higher frequencies allow for smaller transformers, but increase some magnetic losses. Better steel means lower loss, and moves the optimal point up. But I don't find any good reference for actually choosing. Gah4 (talk) 02:28, 4 November 2017 (UTC)

I think we're overthinking here. Much of California was at 50 Hz till well after WW II. I suspect the reasons have nothing to do with transformer steel. --Wtshymanski (talk) 03:47, 4 November 2017 (UTC)

UK 110V?

Do we have an article on 110V in the UK, for temporary installations on building sites etc. I can't find one, but it's an important topic. Andy Dingley (talk) 19:54, 6 September 2017 (UTC)

A passing mention at Split-phase_electric_power#Applications is the only one I know of. --Wtshymanski (talk) 22:29, 6 September 2017 (UTC)

Nothing at Electrical wiring in the United Kingdom which is where a sensible person would look. --Wtshymanski (talk) 22:45, 6 September 2017 (UTC)

Now there's a little there. Let's make a deal: the Brits will write about the American stuff, and we Norteamericanos will write about the British stuff. --Wtshymanski (talk) 20:14, 11 November 2017 (UTC)

DC

The recent removal of "almost always" makes sense. But are there still any places? Small towns in some far away country? That have a DC public power system? I suppose not counting a farm with its own generator. For many years, there were AC/DC radios and television sets, which means no power transformer. It is also a warning that parts of the chassis might be at line voltage. But there may have been some DC power systems around. Gah4 (talk) 06:11, 12 January 2018 (UTC)

The last public DC supply of which I was aware was turned off in 2007. It was in the small town of Manhattan, NY, in the far away country of USA. See https://cityroom.blogs.nytimes.com/2007/11/14/off-goes-the-power-current-started-by-thomas-edison/ FF-UK (talk) 10:09, 12 January 2018 (UTC)

The burden of proof would be on the editor who wishes to add "almost always". At this point I don't see a source which supports this, nor any extant "counter-examples". –dlthewave ☎ 13:23, 12 January 2018 (UTC)

Well, burdon of proof is kind of funny. Not saying "almost always" implies "always", which also has a burden of proof. Prove that there are no DC systems anywhere in the world? Gah4 (talk) 05:53, 13 January 2018 (UTC)

Mains current limitation (rating)

User:Wtshymanski deleted the following addition to the lead with the comment: (this is so vague as to be meaningless and a waste of the reader's time, no matter what regional dialect it's written in):

"For most purposes, the mains can be considered to be a practical voltage source, capable of supplying any required current at the reference voltage; failure, except for brief transients, can be regarded as a power quality issue. However, most electrical service mains have a maximum current rating, determined by the current-carrying capacity of the service wiring between the power grid transformer and distribution board. Most new residential installations in the U.S. are 200amp mains. In older installations, 60amp and 100amp residential mains supplies were common."

What's vague about it? We say in voltage source that the mains is such a thing, without further ado, and it's evidently not vague there. Anyone who isn't clear what a voltage source is, can follow the link. The mains has a distinctly different property than a familiar transformer, whose output voltage drops as more current is demanded. If the mains ever behaved that way, we'd complain to the power company, because it isn't supposed to. That property is correctly termed 'voltage-source'. Not an ideal one, a practical one, a very good one for most purposes, as stated. But we can't draw an arbitrary amount of current from it, as an abstract voltage-source implies - there are limits imposed by the breakers on individual circuits. If we install higher-rated breakers, we'll ultimately come up against the current limit imposed by the wiring to our residence from the power company transformer. In the United States at least, that wiring has standardized rating of 200A. If we attempt to draw any more current than that, we will blow the mains breaker which protects that wiring. Is any of this not at all clear? I worded it succinctly in the text I inserted. I can easily convert it to a more colloquial tone, if that's the issue. Sbalfour (talk) 17:00, 9 November 2017 (UTC)

"Most purposes" is weaslley. Calling it a "voltage source" smacks of circuit theory; anyone who's had to deal in the real world with the vagaries of wall outlets isn't ever going to compare them to those creations of lecture-hall chalkboards. "Most electrical services have a maximum current rating" is typical Wikipedia ass-covering, because we daren't say that *every* electrical service has a maximum rating, because *then* we'd have to Google for some on-line copy of a textbook that says this bloody obvious platitude. Anyone nerdly enough to read through 100 kilobytes of our precious "golden prose" already has a suspicion or intuitive appreciation that he can't run all of Scranton PA off her wall plug. The whole paragraph smacks of saying nothing using the most possible words. We're not here to practice our beautiful penmanship, we're her hopefully to give a read useful information with the minimum amount of pompous wind-bagging. But that's only my take on it, and certainly not representative of Sacred Consensus. --Wtshymanski (talk) 20:51, 10 November 2017 (UTC)

The dual to voltage source is current source, which works pretty much equally well in circuit theory. If not for incandescent lamps, mains power might have gone for a current source more appropriate for arc lamps. (Not likely, but interesting to wonder about.) With the current (ha ha) system, one can design systems assuming a reasonably constant voltage. One then determines the current requirements and completes the design as appropriate. It does seem reasonable to me to say that it is a voltage source, and supply the link for those who want to know more. Gah4 (talk) 22:45, 10 November 2017 (UTC)

Sbalfour, you are, of course, correct. However, Wtshymanski has a tendency to demonstrate his belief that he has ownership of certain articles, eg his repeated deletion of the Terminology section in Nema connectors, which he has attempted to justify with the comment "isn't an article on plugs and sockets a stupid thing to have in an encyclopedia in the first place?" 50.248.126.230 (talk) 02:59, 11 November 2017 (UTC)

Hmmmm... I'm not in a position to judge Wtshymanski. He has reverted my change and I cannot now touch it, because I will not engage in an edit war. It's now a matter of consensus. If I cannot convince him (possibly by rewording), and other editors do not support including the material, we should move on. So I'm weighing what ya' all think. Sbalfour (talk) 03:37, 11 November 2017 (UTC)

An ideal voltage source supplies unlimited current. A practical one has limits. I am for keeping it in, but I won't miss it much if it isn't. Gah4 (talk) 10:41, 11 November 2017 (UTC)

We love to drag in sciencey-sounding big words in a Wikipedia article and then painfully construct forests of obfuscation to explain why this article isn't exactly about the big words. Wouldn't it save a lot of the user's time if we didn't show off how many peripheral things we can think of that pertain to a topic, and just write about the *topic*? (Not falling for the diversion..fool me once, shame on you, fool me 32767 times, shame on me). --Wtshymanski (talk) 20:12, 11 November 2017 (UTC)

Since its written like unverified opinion and its a WP:LEAD paragraph that doesn't summarize the body it should be removed. Someone needs to add this material to the article first with reference, then summarize that following WP:TONE. Fountains of Bryn Mawr (talk) 20:25, 11 November 2017 (UTC)

Ok, I can do that, you're quite right. But even if I do, Wtshymanski won't buy it. I have to go back to an example of a transformer: it says "12V @ 3A", but it hardly ever delivers 12V; the voltage depends on load. The label isn't wrong, but it behaves differently than the mains, and I ask why? I could try to put a couple thousand watt resister across the mains to demonstrate that voltage drops with load, just like the transformer, because I *know* it should. Actually, that's called a space heater, and the voltage doesn't drop. We can't just dismiss it and say the mains was designed that way... the transformer was designed to deliver 12V and doesn't. The mains behavior is prominent, and we don't make note of that. Sbalfour (talk) 20:49, 11 November 2017 (UTC)

I would highly recommend the experience of metering an outlet while loading it up - even at 230 volts, with a DMM, you'll very soon see just how "soft" your branch circuit is. There's a reason why motors are stamped with a 115 nameplate for use on a 120 volt branch circuit. --Wtshymanski (talk) 22:55, 11 November 2017 (UTC)

At some point going back, there are voltage regulating (tap switching) transformers. Since incandescent lamps are somewhat sensitive to voltage, power systems try to keep the voltage pretty close. I haven't notice for a while (especially since our house has mostly fluoresent lamps), but at night, when the load is low, you can sometimes see changes in lamps with load. Smal l transformers keep cost down by using the smallest wire that they can. And if it powers something with a regulator, that is fine. Gah4 (talk) 06:00, 13 January 2018 (UTC)

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25 Hz

At one time, some of North America ran on 25 Hz. A horrible frequency, as the flicker could fall into the visible range. I need to research where and when. There's a very secondary reference in some 1950s SF, plus stuff I recall from high school. Henry Troup (talk) 05:14, 17 December 2008 (UTC)

Have you had a look at Utility frequency? I even found some references and added them. Also look at Thomas P. Hughes, Networks of Power: Electrification in Western Society 1880-1930, The Johns Hopkins University Press,Baltimore 1983 ISBN 0-8018-2873-2 --Wtshymanski (talk) 16:23, 17 December 2008 (UTC)

Considerable parts of upstate New York were 25Hz in the early days, as that was the frequency used by the original generators at Niagara. In later years, the 25Hz generators were retained but run through rotary frequency converters to obtain 60Hz. There were also areas of 50Hz in the U.S., such as some parts of southern California. Los Angeles, for example, changed from 50 to 60Hz sometime in the later 1920's, and there was an official program to replace or modify the many synchronous clocks in use. 97.84.107.236 (talk) 18:32, 20 August 2015 (UTC)

Prior to voltage and frequency standardization, the primary user of power would dictate the standards and this was usually based on the fact that they were not only a large user, but actually started a utility company to provide the community with electricity. If the large user and utility company ran a lot of smaller motors and didn't need large rotary converters, power was supplied either as DC or a higher (at least 40 Hertz) AC frequency. If the large industry had large motors or needed rotary converters, power was more commonly supplied at 25 Hertz. If the power company was a railroad either 25 hertz used with Rotary Converters or DC was supplied. Voltage standardization was first, on AC systems the distribution networks were commonly configured as either 2200 volts single phase, 2200 volts delta, or 2200/3800 Wye (aka star). As the systems progressed many 220 volt systems went to 110 or 110/220 volts depending on the design. DC and higher than 60 Hertz AC systems were the first phased out, later as described above 50 Hertz went to 60 Hertz. The use of 25 Hertz in residential systems was phased out around Niagara falls in the 1950s and most DC residential systems phased out after WWII. In Arizona 25 Hertz stayed until the 1970s which was rather late. The last 25 Hertz utility system was turned off in 2006 when the customers did not wish to pay their share to rebuild it. Significant engineering challenges resulted due to this lack of standardization. When supporting 25 Hertz, modifications were usually almost mandatory. Radios had to have transformers changed and filter sections modified, even radios capable of 50 and 60 Hertz AC and DC operation needed modification for 25 Hertz. Early adopters of television needed modified transformers installed in their sets as well as filter section changes. Fluorescent lamp systems required special ballasts (this is also true of 50 Hertz and DC) and some manufacturers had special 25 Hertz lamps with the ends shielded to reduce the visibility of flicker. The only thing more difficult with fluorescent lamps was DC. Kb3pxr (talk) 22:44, 29 March 2018 (UTC)

Glen Echo Park was one early place with carnival rides powered by excess power from electric streetcars. Especially when ridership was lower at night, power would be available for carnival rides. It isn't so hard to run fluorescent lamps on DC with a resistive ballast, but they aren't so efficient as on AC. Also, you should switch polarity once in a while to equalize cathode wear. Gah4 (talk) 00:28, 30 March 2018 (UTC)