Talk:Mains electricity

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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)

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)

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)

Contents

[edit] 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)

[edit] 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.

[edit] US translation

I am far from knowledgeable in the field, but in the US, and US-dominated online forums such as /., I often hear/see the "domestic electrical power supply" referred to as the "grid". It might be useful to add that term, rather than simply say that the term "mains" is not used in the US/Canada. --Danny Rathjens 07:07, 2004 Aug 23 (UTC)

The term "Hydro" is a regional term in Canada - I suspect it's called that in provinces where the power companies have "hydro" in their name - Quebec Hydro, BC Hydro, Hydro One (Ontario), Manitoba Hydro. I've lived in Alberta, Saskatchewan, and Nova Scotia and the only people I've heard call it "hydro" have been from Ontario. --Thavron (talk) 06:06, 17 February 2008 (UTC)

[edit] 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)

[edit] 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)

[edit] 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)

[edit] 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).

[edit] 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)

[edit] 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)

[edit] "not using capacity" of supply

Um, I dunno what the usual practice is in the USA, but here in Australia there are plenty of devices - most of them for heating of one kind or another - that use the full capacity of the standard outlets. Electric kettles, electric frypans, and space heaters that use the full 10 amperes available are commonplace. Anybody like to put the case for retaining that claim in the article?--Robert Merkel 07:43, 21 June 2007 (UTC)

For every appliance that uses the full capacity, I suspect you'll find 3 or 4 that use a tiny fraction. Table lamps, clocks, radios, TV,computers, printers, modems, "wall-wart" chargers for cell phones and etc., hand-held power tools,trouble lights, electric foot massage baths, power pencil sharpeners, fans, mixers, blenders, food processors, electric brooms, fish tank compressors, humidifiers, dehumidifiers, night lights, CO detectors, block heaters, mosquito killers, electric string trimmers, barbeque rotisserie motors, Christmas lights, etc. etc. Qualify the statement if you must, but I think it's fair to say that many portable appliances don't need even 50% of a typical wall receptacle capacity. --Wtshymanski 17:47, 21 June 2007 (UTC)
The vast majority of appliances available come nowhere near using the full 10A available from a standard Australian socket outlet - mostly appliances with heating elements or airconditioners are the ones that do... Bear in mind that it's common practice to wire a power circuit with 2.5mm² PVC insulated cabling which is good for no more than 20A - if the majority of appliances used the full 10A there'd be a maximum allowed number of outlets per circuit of 2... Instead the wiring rules merely state that a circuit must work as intended and within reason the onus is on the electrician to spread load evenly among multiple circuits to avoid nuisance tripping of breakers... Single-phase appliances that use more than 10A are available as well hence the existance of 15A, 20A, 25A and 32A single phase outlets (the last 2 admittedly being very rare)... Higher power devices of course use 400V - that is 230V in a 3-phase star (wye) configuration... Anthrass 08:22, 13 July 2007 (UTC)
Indeed there are lots of small appliances but at least here in the UK is it quite normal to plug a washing machine, a dishwasher or a 3KW heater into a normal socket. Those appliances need special circuits on the american system (not such an issue for washing machines and dishwashers because they need special plumbing too but not being able to put a decent sized fan heater in your bedroom whent the central heating breaks down seems like it would be quite a pain. Plugwash (talk) 16:30, 20 November 2007 (UTC)
True - 15A outlets are increasingly common here in Australia (especially in domestic laundries and the like) partly because of the proliferation of washers which heat their own water (rather than connecting to the hot water supply) and driers - some of which draw more than the 10A available from a standard outlet... Anthrass (talk) 07:25, 15 December 2007 (UTC)

[edit] 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)

[edit] 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)

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)

[edit] 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)