Talk:Mains electricity

From Academic Kids

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)

---

The article says that those countries that when Europe was harmonised to 230V those countried 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)

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)

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)